- Boost - lists.preview.boost.org

cstring_view
by Klemens Morgenstern 14 May '22

14 May '22

Hi y'all, I've hacked together a cstring_view class and would like to ask if it could be included in boost.utility or boost.core. https://gist.github.com/klemens-morgenstern/fc02dab8b37fc77ac80efbca30f297cf The main motivation is to have a view that works with C-APIs. I also need the char_traits for dealing with odd char semantics for some system APIs. (e.g. environment keys on windows are char-insensitive but preserving).

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Re: [boost] Boost Digest, Vol 6704, Issue 1 - The Future of C++ and Boost - C++ Modules
by Benedict Bede McNamara 14 May '22

14 May '22

I believe that modules are so important that you should drop everything and aim to release a modular version of Boost. I believe this because I used Boost’s serialization to write the General Theory of Databases in C++ (I already had that theory in C# and Java). While that succeeded I upgraded I++ to use C++ Modules. I couldn’t get Boost’s header based system working with the modular form of databases. So I had to drop Boost altogether. I believe that if Boost is to remain relevant it must be expressed in Modular Form immediately. You should target a release for a week or two in the future. I sent Boost a starting module of about 15,000 lines of code. It compiles OK but needs work to link. You can pack the entire Boost library into a single .ixx file. You should target Microsoft’s compiler first then expand support as other compilers implement modules. That is, you should aim to make a quantum leap to ISO C++ 20 standard immediately. Cheers, Benedict Bede McNamara, 1st Class Honours, Pure Mathematics. From: boost-request(a)lists.boost.org Sent: Friday, 13 May 2022 12:24 PM To: boost(a)lists.boost.org Subject: Boost Digest, Vol 6704, Issue 1 Send Boost mailing list submissions to boost(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.boost.org/mailman/listinfo.cgi/boost or, via email, send a message with subject or body 'help' to boost-request(a)lists.boost.org You can reach the person managing the list at boost-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost digest..." The boost archives may be found at: http://lists.boost.org/Archives/boost/ Today's Topics: 1. Re: MySql review (Ruben Perez) 2. Re: Review of Boost.MySql (Ruben Perez) 3. Re: Future of C++ and Boost (Andrey Semashev) 4. Re: Future of C++ and Boost (Gavin Lambert) 5. Re: Boost MySQL Review Starts Today (Alan de Freitas) ---------------------------------------------------------------------- Message: 1 Date: Thu, 12 May 2022 20:50:22 +0200 From: Ruben Perez <rubenperez038(a)gmail.com> To: boost(a)lists.boost.org Cc: Phil Endecott <spam_from_boost_dev(a)chezphil.org> Subject: Re: [boost] MySql review Message-ID: <CACR-md+=90n+Eh1HNCnDQNHcBtfKgYrohg3O-HryL6Wyts8_pA(a)mail.gmail.com> Content-Type: text/plain; charset="UTF-8" On Wed, 11 May 2022 at 20:23, Phil Endecott via Boost <boost(a)lists.boost.org> wrote: > > Here is my review of Ruben Perez's proposed MySql library. Hi Phil, thank you for taking your time to write a review. > > Background > ---------- > > I have previously implemented C++ wrappers for PostgreSQL and > SQLite, so I have some experience of what an SQL API can look > like. I know little about ASIO. > > I have also recently used the AWS SDKs for C++ and Javascript to > talk to DynamoDB; this has async functionality, which is interesting > to compare. > > I confess some minor disappointment that MySql, rather than > PostgreSQL or SQLite, is the subject of this first Boost database > library review, since those others have liberal licences that > are closer to Boost's own licence than MySql (and MariaDB). But > I don't think that should be a factor in the review. > > > Trying the library > ------------------ > > I have tried using the library with > > - g++ 10.2.1, Arm64, Debian Linux > - ASIO from Boost 1.74 (Debian packages) > - Amazon Aurora MySql-compatible edition > > I've written a handful of simple test programs. Everything works > as expected. Compilation times are a bit slow but not terrible. > > > > The remainder of this review approximately follows the structure > of the library documentation. > > > Introduction > ------------ > > I note that "Ease of use" is claimed as the first design goal, > which is good. I think I failed to make the scope of the library clear enough in this aspect. The library is supposed to be pretty low level and close to the protocol, and not an ORM. I list ease of use here in the sense that * I have tried to abstract as much of the oddities of the protocol as possible (e.g. text and binary encodings). * The library takes care of SSL as part of the handshake, vs having the user have to take care of it. * The library provides helper connect() and close() functions to make things easier. * The object model is as semantic as I have been able to achieve, vs. having a connection object and standalone functions. * The value class offers stuff like conversions to make some use-cases simpler. I guess I listed that point in comparison to Beast or Asio, which are even lower level. Apologies if it caused confusion. > > I feel that some mention should be made of the existing C / C++ > APIs and their deficiencies. You should also indicate whether or > not the network protocol you are using to communicate with the > server is a "public" interface with some sort of stability > guarantee. (I guess maybe it is, if it is common to MySql and > MariaDB.) Updated https://github.com/anarthal/mysql/issues/50 on comparison with other APIs. The network protocol is public and documented (although the documentation is pretty poor). It's indeed a pretty old protocol that is not being extended right now, and it's widely used by a lot of clients today, so there is very little risk there. > > > Tutorial > -------- > > The code fragments should start with the necessary #includes, > OR you should prominently link to the complete tutorial source > code at the start. Raised https://github.com/anarthal/mysql/issues/71 to track it. > > You say that "this tutorial assumes you have a basic familiarity > with Boost.Asio". I think that's unfortunate. It should be > possible for someone to use much of the library's functionality > knowing almost nothing about ASIO. Remember your design goal of > ease-of-use. In fact, it IS possible to follow the tutorial with > almost no knowledge of ASIO because I have just done so. If you are to really take advantage of the library (i.e. use the asynchronous API), you will need some Asio familiarity. I'd say a very basic understanding is enough (i.e. knowing what a io_context is). If you think this comment is misleading, I can remove it. But I don't think this is the right place to provide a basic Asio tutorial. > > You have this boilerplate at the start of the tutorial: > > boost::asio::io_context ctx; > boost::asio::ssl::context ssl_ctx (boost::asio::ssl::context::tls_client); > boost::mysql::tcp_ssl_connection conn (ctx.get_executor(), ssl_ctx); > boost::asio::ip::tcp::resolver resolver (ctx.get_executor()); > auto endpoints = resolver.resolve(argv[3], boost::mysql::default_port_string); > boost::mysql::connection_params params ( > argv[1], // username > argv[2] // password > ); > conn.connect(*endpoints.begin(), params); > // I guess that should really be doing something more > // intelligent than just trying the first endpoint, right? The way to go here is providing an extra overload for connection::connect. Raised https://github.com/anarthal/mysql/issues/72 to track it. > > I would like to see a convenience function that hides all of that: > > auto conn = boost::mysql::make_connection( ...params... ); > > I guess this will need to manage a global, private, ctx object > or something. If you take a look to any other asio-based program, the user is always in charge of creating the io_context, and usually in charge of creating the SSL context, too. If you take a look to this Boost.Beast example, you will see similar stuff: https://www.boost.org/doc/libs/1_79_0/libs/beast/example/http/client/sync-s… I'm not keen on creating a function that both resolves the hostname and connects the connection, as I think it encourages doing more name resolution than really required (you usually have one server but multiple connections). I may be wrong though, so I'd like to know what the rest of the community thinks on this. > .port = 3306, // why is that a string in yours? It is not "mine", it's just how Asio works. Please have a look at https://www.boost.org/doc/libs/1_79_0/doc/html/boost_asio/reference/ip__bas… > make_connection("mysql://admin:12345@hostname:3306/dbname"); I guess you're suggesting that make_connection also perform the name resolution, the physical connect and the MySQL handshake? I'm not against this kind of URL-based way of specifying parameters. I've used it extensively in other languages. May be worth reconsidering it once Vinnie's Boost.Url gets accepted. > > Now... why the heck does your connection_params struct use > string_views? That ought to be a Regular Type, with Value > Semantics, using std::strings. Is this the cult of not using > strings because "avoid copying above all else"? I may have been a little too enthusiastic about optimization here. > > Another point about the connection parameters: you should > provide a way to supply credentials without embedding them > in the source code. You should aim to make the secure option > the default and the simplest to use. I suggest that you > support the ~/.my.cnf and /etc/my.cnf files and read passwords > etc. from there, by default. You might also support getting > credentials from environment variables or by parsing the > command line. You could even have it prompt for a password. I don't know of any database access library that does this. The official Python connector gets the password from a string. I think this is mixing concerns. Having the password passed as a string has nothing to do with having it embedded in the source code. Just use std::getenv, std::stdin or whatever mechanism your application needs and get a string from there, then pass it to the library. All the examples read the password from argv. Additionally, having passwords in plain text files like ~/.my.cnf and /etc/my.cnf is considered bad practice in terms of security, I wouldn't encourage it. > > Does MySQL support authentication using SSL client certs? > I try to use this for PostgreSQL when I can. If it does, you > should try to support that too. AFAIK you can make the server validate the client's certificate (that doesn't require extra library support), but you still have to pass a password. > > About two thirds of the way through the tutorial, it goes from > "Hello World" to retrieving "employees". Please finish the hello > world example with code that gets the "Hello World" string > from the results and prints it. My bad, that's a naming mistake - it should be named hello_resultset, instead. It's doing the right thing with the wrong variable name. Updated https://github.com/anarthal/mysql/issues/71 > > > Queries > ------- > > I encourage you to present prepared queries first in the > documentation and to use them almost exclusively in the tutorial > and examples. It can definitely make sense. > > You say that "client side query composition is not available". > What do you mean by "query composition"? I think you mean > concatenating strings together'); drop table users; -- to > form queries, right? Is that standard MySql terminology? I > suggest that you replace the term with something like > "dangerous string concatenation". Yes, I mean that. > > In any case, that functionality *is* available, isn't it! > It's trivial to concatenate strings and pass them to your > text query functions. You're not doing anything to block that. > So what you're really saying is that you have not provided any > features to help users do this *safely*. I think that's a serious > omission. It would not be difficult for you to provide an > escape_for_mysql_quoted_string() function, rather than having > every user roll their own slightly broken version. Definitely not trivial (please have a look at MySQL source code) but surely beneficial, see below. Tracked by https://github.com/anarthal/mysql/issues/69. > > IIRC, in PostgreSQL you can only use prepared statements > for SELECT, UPDATE, INSERT and DELETE statements; if you > want to do something like > > ALTER TABLE a ALTER COLUMN c SET DEFAULT = ? > or CREATE VIEW v as SELECT * FROM t WHERE c = ? You are right, these cases aren't covered by prepared statements. https://github.com/anarthal/mysql/issues/69 tracks it. > tcp_ssl_prepared_statement is verbose. Why does the prepared > statement type depend on the underlying connection type? Because it implements I/O operations (execute() and close()), which means that it needs access to the connection object, thus becoming a proxy object. > I have to change it if I change the connection type?! If that's > unavoidable, I suggest putting a type alias in the connection > type: > > connection_t conn = ....; > connection_t::prepared_statement stmt(.....); Raised https://github.com/anarthal/mysql/issues/73 > > Does MySql allow numbered or named parameters? SQLite supports > ?1 and :name; I think PostgreSQL uses $n. Queries with lots of > parameters are error-prone if you just have ?. If MySql does > support this, it would be good to see it used in some of the > examples. Not AFAIK, just regular positional placeholders. > > Invoking the prepared statement seems unnecessarily verbose. > Why can't I just write > > auto result = my_query("hello", "world", 42); Because this invokes a network operation. By Asio convention, you need a pair of sync functions (error codes and exceptions) and at least an async function, that is named the same as the sync function but with the "_async" suffix. I'm not against this kind of signature, building on top of what there already is: statement.execute("hello", "world", 42); statement.async_execute("hello", "world", 42, use_future); Which saves you a function call. Raised https://github.com/anarthal/mysql/issues/74 > > I also added Query variants where the result is expected to be > > - A single value, e.g. a SELECT COUNT(*) statement. > - Empty, e.g. INSERT or DELETE. > - A single row. > - Zero or one rows . > - A single column. I think this can be useful. I've updated https://github.com/anarthal/mysql/issues/22 to track this. > I don't see anything about the result of an INSERT or UPDATE. > PostgreSQL tells me the number of rows affected, which I have > found useful to return to the application. Please have a look at https://anarthal.github.io/mysql/mysql/resultsets.html#mysql.resultsets.com… > > > resultset, row and value > ------------------------ > > I'm not enthusiastic about the behaviour nor the names of these > types: Resultset is how MySQL calls it. It's not my choice. > > - resultset is not a set of results. It's more like a sequence of > rows. But more importantly, it's lazy; it's something like an > input stream, or an input range. So why not actually make it > an input range, i.e. make it "a model of the input_range concept". > Then we could write things like: > > auto result = ...execute query... > for (auto&& row: result) { > ... > } How does this translate to the async world? > > - row: not bad, it does actually represent a row; it's a shame > it's not a regular type though. > > - value: it's not a value! It doesn't have value semantics! If the library gets rejected I will likely make values owning (regular). > I'm also uncertain that a variant for the individual values > is the right solution here. All the values in a column should > have the same type, right? (Though some can be null.) So I > would make row a tuple. Rather than querying individual values > for their type, have users query the column. Are you talking about something like this? https://github.com/anarthal/mysql/issues/60 > > It seems odd that MySQL small integers all map to C++ 64-bit > types. It is done like this to prevent the variant from having too many alternatives - I don't think having that would add much value to the user. If I implement something like https://github.com/anarthal/mysql/issues/60, each int type will be mapped to its exact type. > > I use NUMERIC quite a lot in PostgreSQL; I don't know if the > MySql type is similar. I would find it inconvenient that it > is treated as a string. Can it not be converted to a numeric > type, if that is what the user wants? MySQL treats NUMERIC and DECIMAL the same, as exact numeric types. What C++ type would you put this into? float and double are not exact so they're not fit. > I seem to get an assertion if I fail to read the resultset > (resultset.hpp:70). Could this throw instead? This assertion is not related to this. It's just checking that the resultset has a valid connection behind it, and is not a default constructed (invalid) resultset. > > Or, should the library read and discard the unread results > in this case? Having a look into the Python implementation, it gives the option to do that. I think we can do a better job here. Track by https://github.com/anarthal/mysql/issues/14 > > But the lack of protocol support for multiple in-flight queries > immediately becomes apparent. It almost makes me question > the value of the library - what's the point of the async > support, if we then have to serialise the queries? As I pointed out in another email, it's a combination of lack of protocol support and lack of library support. Apologies if the documentation is not clear in this aspect. I think there is value in it, though, so you don't need to create 5000 threads to manage 5000 connections. The fact that the official MySQL client has added a "nonblocking" mode seems a good argument. > > Should the library provide this serialisation for us? I.e. > if I async_execute a query while another is in progress, the > library could wait for the first to complete before starting > the second. I would go for providing that bulk interface I talk about in other emails. > > Or, should the library provide a connection pool? (Does some > other part of ASIO provide connection pool functionality that > can be used here?) Asio doesn't provide that AFAIK. It is definitely useful functionality, tracked by https://github.com/anarthal/mysql/issues/19 > > > Transactions > ------------ > > I have found it useful to have a Transaction class: > > { > Transaction t(conn); // Issues "BEGIN" > .... run queries .... > t.commit(); // Issues "COMMIT" > } // t's dtor issues "ROLLBACK" if we have not committed. > Again, how would this work in the async world? How does the destructor handle communication failures when issuing the ROLLBACK? > Klemens Morgenstern makes the point that MySql is a trademark of > Oracle. Calling this "Boost.MySql" doesn't look great to me. > How can you write "The Boost MySql-compatible Database Library" > more concisely? I'm not very original at naming, as you may have already noticed. Using Boost.Delfin was proposed at some point, but Boost.Mysql definitely expresses its purpose better. > > Overall, I think this proposal needs a fair amount of API > re-design and additional features to be accepted, and should > be rejected at this time. It does seem to be a good start > though! > > > Thanks to Ruben for the submission. Thank you for sharing your thoughts, I think there is a lot of useful information here. ------------------------------ Message: 2 Date: Thu, 12 May 2022 21:02:48 +0200 From: Ruben Perez <rubenperez038(a)gmail.com> To: Dominique Devienne <ddevienne(a)gmail.com>, boost(a)lists.boost.org Subject: Re: [boost] Review of Boost.MySql Message-ID: <CACR-mdJntpKJ7x0cX8K4M4wasBWqTR5x9i-7FhygHxmCDL4=cA(a)mail.gmail.com> Content-Type: text/plain; charset="UTF-8" > Indeed. But even your imagined batch interface only works well for > queries/selects, > while for inserts (or updates), the client does not need to just send > a small textual > SQL query, but potentially a bunch of data for the rows too. A true > pipeline allows > sending the rows for a second insert while the first insert is being processed. It would work for inserts too, as values are either part of the query string or part of the statement execute packet. In both cases, part of the request. > Such a mode may be useful for schema creation OTOH. We have large schemas, > with hundreds of tables, indexes, triggers, etc... Done from C++ code > client-side, > not via a DBA manually executing on the server using SQL files and the > native CLI. > For that use-case, the ability to send many DDLs in a single batch > would definitely > save on the round-trips to the server. We try hard to minimize roundtrips! Thanks for sharing this use case, I definitely wasn't aware of it and seems a reason towards implementing multi-statement. > You don't need to necessarily use Google's protobufs library. > There's https://github.com/mapbox/protozero for example, and similarly, a > from-scratch implementation to just encode-decode a specific protocol > can also be written. I wasn't aware of this.Thanks. > > The server sends several resultsets after that. I haven't focused a lot on > > this because it sounded risky (in terms of security) for me. > > Not sure what's risky here. Maybe I'm missing something. I was just imagining users concatenating queries. May be a misconception, yours is a legitimate use case. > Note that PostgreSQL's COPY is not file-specific, and a first-class citizen > at the protocol level, depending on a pure binary format (with text mode too). > I use COPY with STDIN / STDOUT "files", i.e. I prepare memory buffers and > send them; and read memory buffers, and decode them. No files involved. Unfortunately, that does not seem to be the case for MySQL. You issue the LOAD DATA statement via a regular query packet, and the server returns you another packet with the file path it wants. You then read it in the client and send it to the server in another packet. I've made it work with CSV files, and I'd say it's the only format allowed, AFAIK. > Maybe our use-case of very large data (with large blobs), *and* very > numerous smaller data, > that's often loaded en-masse, by scientific desktop applications, and > increasingly mid-tier services > for web-apps, is different from the more common ecommerce web-app > use-case of many people. It is good to hear different use cases than the regular web server we all have in mind. It will help me during further development. > > When I evaluate DB performance, I tend to concentrate on "IO" performance, > in terms of throughput and latency, independent of the speed of the > SQL engine itself. > There's nothing I can do about the latter, while the way one uses the Client API > (or underlying protocol features) is under my control. So I do mostly > INSERTs and > SELECTs, with and without WHERE clauses (no complex JOINs, CTEs, etc...). > > Because we are in the scientific space, we care about both many small rows > (millions, of a few bytes to KBs each at most), and a few (hundreds / thousands) > much larger rows with blobs (with MBs to GBs sizes). The truly large > "blobs" (files) are > kept outside the DB, since mostly read only (in the GBs to TBs sizes each, that > can accumulate to 2.6 PB for all a client's data I heard just > yesterday for example). > > I'll also compare inserting rows 1-by-1, with and without prepared statements, > to inserting multi-rows per-statement (10, 100, 1000 at a time), to the "bulk" > interface (COPY for PostgreSQL, LOCAL for MySQL, Direct-Path load in OCI). > For example with SQLite: > https://sqlite.org/forum/forumpost/baf9c444d9a38ca6e59452c1c568044aaad50bba… > (SQLite as no "bulk" interface, doesn't need one, since "embedded" > thus "zero-latency") > > For PostgreSQL, we also compared text vs binary modes (for binds and > resultsets). > > For blobs, throughput of reading and writing large blobs, whole and in-part, > with different access patterns, like continuous ranges, or scattered inside). > > A very important use-case for us, for minimizing round-trips, is how > to load a subset of rows, > given a list of primary keys (typically a surrogate key, like an > integer or a uuid). For that, > we bind a single array-typed value for the WHERE clause's placeholder > to the query, > and read the resultset, selecting 1%, 5%, 10%, etc... of the rows from > the whole table. > (selecting each row individually, even with a prepared query, is terribly slow). Thanks for sharing. It will definitely help me during benchmarking. Regards, Ruben. ------------------------------ Message: 3 Date: Thu, 12 May 2022 23:39:41 +0300 From: Andrey Semashev <andrey.semashev(a)gmail.com> To: boost(a)lists.boost.org Subject: Re: [boost] Future of C++ and Boost Message-ID: <db0e5cf4-12b6-cc2f-da78-d65f76f899d2(a)gmail.com> Content-Type: text/plain; charset=UTF-8 On 5/12/22 21:48, Marshall Clow via Boost wrote: > On May 12, 2022, at 11:34 AM, Robert Ramey via Boost <boost(a)lists.boost.org> wrote: >> >> On 5/12/22 11:30 AM, Robert Ramey via Boost wrote: >>> On 5/12/22 9:55 AM, John Maddock via Boost wrote: >> >>> wow - that would be a big one. codecvt is the fundamental component to support wchar is it not? Does this mean that wchar is gone also? If so what replaced it? etc.... >> >> FWIW - I don't see any notice of such deprecation here: https://en.cppreference.com/w/cpp/header/codecvt > > Its in green - at the top: > codecvt_utf8 > <https://en.cppreference.com/w/cpp/locale/codecvt_utf8> > (C++11)(deprecated in C++17) Also here: http://eel.is/c++draft/depr.locale.stdcvt#depr.codecvt.syn ------------------------------ Message: 4 Date: Fri, 13 May 2022 13:20:24 +1200 From: Gavin Lambert <boost(a)mirality.co.nz> To: boost(a)lists.boost.org Subject: Re: [boost] Future of C++ and Boost Message-ID: <4d5d8961-85f3-979a-f69d-be9a9f02c3fc(a)mirality.co.nz> Content-Type: text/plain; charset=UTF-8; format=flowed On 13/05/2022 06:30, Robert Ramey wrote: > On 5/12/22 9:55 AM, John Maddock wrote: >> Watch out - all of <codecvt> is deprecated in C++17, I think you're >> relying only on <local> and may be OK though... > > wow - that would be a big one.? codecvt is the fundamental component to > support wchar is it not?? Does this mean that wchar is gone also?? If so > what replaced it? etc.... wchar_t is still around (although char8_t and std::u8string are the new hotness), it's just the conversion functions that are deprecated. I guess you're just not supposed to convert anything any more. More seriously, AFAIK there's no plans to actually remove it until/unless an actual replacement gets standardised. But I think in the meantime they'd rather you use something like the ICU library for conversions instead. Although it wouldn't surprise me if, in not wanting to take a dependency on an external library (and not wanting to continue using an officially deprecated standard function), a lot of libraries/apps will write their own subtly-broken conversion routines instead... ------------------------------ Message: 5 Date: Thu, 12 May 2022 23:24:19 -0300 From: Alan de Freitas <alandefreitas(a)gmail.com> To: boost(a)lists.boost.org Subject: Re: [boost] Boost MySQL Review Starts Today Message-ID: <CAHpLXUiEEA4zjeMVO_EKgoMTGYv3t49hG0MjOrFqXx93K9SVHg(a)mail.gmail.com> Content-Type: text/plain; charset="UTF-8" Hi! Here's my review. Boost.MySql is an impressive library. I would like to thank Rub?n for that. It implements the complete protocol from the ground up with async functionalities and certainly involved a lot of work. The documentation is extensive, goal-oriented, and helpful. The async operations support cancellation and the examples with coroutines are beautiful. During this review, I was impressed at how easy it works and I've noticed a few points in the API that have also been brought up in previous reviews and could be improved. Some other issues could also be better highlighted in the documentation, which would avoid many problems. The overall recommendation in this review is acceptance conditional on some fixes. ## Value > Will the library bring additional out-of-the-box utility to Boost? The library is very good news considering our recent discussions about the future of Boost, where providing more protocol implementations comes up frequently. I wish more people would make this kind of contribution. > What is your evaluation of the potential usefulness of the library? Others have questioned the benefit of the library when compared to sqlpp11 or any wrapper around the C API. The main difference is other libraries are high-level but this is a discussion still worth having from the point of view of users. I was thinking about the transition cost from Boost.MySQL to any other SQL database, since many applications have the requirement/necessity of allowing different SQL databases. In sqlpp11, the user can just change the backend. The user could use Boost.MySQL as an sqlpp11 backend and that would have the same effect. However, I think Rub?n mentioned this is not possible at some point. I'm not sure whether this is just for the async functionality. In the same line, I wonder if a library for Postgres or Sqlite would be possible with a similar API, which could also solve the problem, although I'm not sure anyone would be willing to implement that. If we did, we could have the convenience of sqlpp11 and the ASIO async functionalities of Boost.Mysql for other DBs. The library really provides ease-of-use, when we consider what it provides and how low-level it is. However, unlike in other libraries like Boost.Beast, Boost.MySql users might not be sold into the Asio way of doing things. Applications that require access to databases might be making sparse database requests where the Asio asynchronous model is not as useful. Highlighting these differences in the docs is important. Asio takes some time to learn, and I guess for a user not used to Asio, already understanding Asio does not sound like the ease of use. The docs could focus on the protocol before moving on to the asynchronous functionality. I'm also a little worried about the maintainability of the library and protocol changes and how this could impact boost as a whole. Should we really announce it as compatible with MariaDB? What direction would the library take if they diverge? How often does the protocol change or is extended? Is Ruben going to stick around if the protocol changes? How hard would it be for someone to understand the code and implement extensions? Can a user be sure it's always going to provide the same features and be as reliable as the C API? I don't have the answer to these questions, but it's something that got me wondering. I guess this kind of question is going to come up for any library that is related to a protocol. I don't know if the name "MySql" can be used for the library, as it belongs to Oracle. I'm not saying it can't. I'm really saying I don't know. I'm not a lawyer and I don't understand the implications here. But this should be considered, investigated, and evidence should be provided. The library is also compatible with MariaDB and the name "MySql" might not reflect that. Maybe there's a small probability it might be compatible with some other similar DB protocol derived from MySql in the future? As others have mentioned, the protocol is strictly sequential for a single connection, and this might have some implications for the asynchronous operations the library provides. - No two asynchronous MySql query reads can happen concurrently. While this still has value among other Asio operations, like a server that needs the DB eventually, the user needs to be careful about that. Maybe it would be safer if all MySql operations were on some special kind of strand. Or maybe the library could provide some "mysql::transaction_strand" functionality to help ensure this invariant for individual queries in the future. - A second implication is that some applications might find the asynchronous functionalities in Boost.Mysql not as useful as asynchronous functionalities in other protocols, like the ones in Boost.Beast. This depends on how their applications are structured. Since this is the main advantage over the C API, these users may question the value of the library and the documentation should discuss this more explicitly. - These implications could become irrelevant if the library provides some kind of functionality to enable a non-blocking mode. I have no idea how the MySql client achieves that. ## API > What is your evaluation of the design? Will the choice of API abstraction model ease the development of software that must talk to a MySQL database? I like how the API is very clean compared to the C API, even when including the asynchronous functionality. This would be a reason for using the library, even if I only used the synchronous functions. I'm worried about the lack of possibility of reusing memory for the results, as the interface depends on vector. This is not the usual Asio pattern. These vectors look even weirder in the asynchronous callbacks: - People have their containers/buffers and I would assume reading into some kind of existing row buffer would be the default interface, as is the case with other Asio read functions. In other words, read_many and read_all should work more like read_one. - Not returning these vectors is the common pattern in Asio: the initiating function receives a buffer for storage and the callback returns how many elements were read. Note that the buffer size already delimits how many elements we should read. - If we return vectors, async operations would need to instantiate the vector with the custom allocator for the operation. The callback wouldn't use std::vector<T> then. I would be std::vector<T, very_long_allocator_name> for every query callback, which is inconvenient. Using only std::vector<T> in the callback is not only inconvenient but dangerous because it would be the wrong allocator and everything would need to be copied. - One problem I see without the vectors is that each row would still need to allocate memory internally because of their dynamic size. I don't know the best solution for that second problem unless we have some sort of static size row/tuple, which does make sense since the user should know the number of columns at compile time. The library provides read_one, read_all, and read_many, but no "read_some". Besides the implication of a buffer to the initiating function, I would imagine reading as much as possible and parsing that to be the usual best strategy in this kind of an operation since we have a stream and we don't know how much data is available to read yet. Unfortunately, read_one, read_all, and read_many don't allow that. Unless read_many can already read less than the max number of rows in intermediary calls, which I don't think is the intention. It might also be useful to replicate the naming conventions Asio uses to read some or read all of the data. If "value" is intended to encapsulate the variant type, "value::to_variant" seems dangerous. The variant supports lots of types, which indicates the probability the internal design might need to change to fit new user demands is high. This could also need to change according to protocol extensions, and changing any of these types would break the API. If "value" already represents what it needs to represent, "value::to_variant" may not need to be exposed unless there's a lot of user demand for that. There is also an existential value/reference problem with "value": - The internal variant type includes a string_view whose string is owned by the row. This seems kind of dangerous or at least misleading. We have a reference type that's called "value", while this is more like a const "field view" or something. - At the same time, it's not a view either because I assume this is mutable, and updating numbers would not update the row. - The other values in the variant are value types, which makes "value" both a value and a reference type depending on the column type. - A reference type seems appropriate here because we don't want to copy all the data when iterating the results, but we need some other pattern for "value". A const view is especially useful because we might be able to keep value types for numbers, etc... Encapsulating the variant is also helpful here. - Calling a type "value" is a bad indication anyway. Any value is a "value". As others have mentioned, "value::get_std_optional" is unusual. It may not look problematic at first but it has a number of problems: 1) We have a dangerous precedent because we could also say we need to support all other boost/std equivalents in the library, such as the string_view the library uses at many places. 2) We are including and depending on two libraries when we know almost for sure the user is only using one of them: If there's no std::optional in the supported platform, we just need boost::optional. If you are requiring a C++ standard where std::optional is available, then we just need std::optional. 3) This is also not very useful if the user has both boost::optional and std::optional, because the code would still need to be refactored from get_optional to get_std_optional or vice-versa if the user decides to change it. This could be solved with some BOOST_MYSQL_USE_STD_OPTIONAL or BOOST_MYSQL_USE_STD_STRING_VIEW, etc., but this would also invalidate the distinction. 4) This would make the API inconsistent in case Boost moves to a C++17 minimum at some point in the future, replacing boost classes, as we have been discussing C++14 lately. Both get_optional and get_std_optional would return the same type. Also, if std::optional is the *standard* type, it should not be the one whose function needs clarification with a longer name "get_std_optional". 5) This doesn't need to be a member function, which indicates it shouldn't be a member function in this case. The class is internally representing only one of these and conversions will happen anyway. A user in the >C++17 intersection can easily implement their own to_std_optional free function outside the class. If I understood the documentation correctly, it's also problematic to use an empty optional for both a null value and an invalid result. They are simply not the same thing. Libraries always differentiate an invalid state from null in a field. This is especially relevant because the documentation warns us against using the "is_convertible_to" pattern over "get_optional" because "is_convertible_to" is unnecessarily slow. By the way, it would be nice to explain why "// WARNING!! Inefficient, do NOT do" is true. I wouldn't expect that to cost more than creating the optional value. The documentation states that the behavior of relational operators may change in the future. What do other libraries do about these comparisons? We probably don't want something like PHP, where "20" == 20 so that we need some kind of "20" === 20 in the future, but the documentation implies we also don't want "value(std::int64_t(200)) > value(std::uint64_t(200))" to fail. The library makes the whole thing particularly tricky with number types because not checking the proper number type in the variant would return invalid/null even when the number could be stored in a variable of another number type perfectly fine, which is even worse when both invalid and null are presented by the same empty optional. About the "resultset": - If "resultset" is a table, the "set" part of the name might be a little misleading in C++ as the results are in a deterministic sequence, even though this is what MySQL may call a similar concept. However, I imagine there's no equivalent concept in MySql for this specific Asio-async-lazy-fetching functionality itself. - This class is more like a "table", "frame", "vector", "list", or just "result". However, after all the steps of "connect", "prepare", and "execute", the name "result" gives the impression that the results are finally there, but this is just another stream object like a "result fetcher" or something. - Since the protocol is strictly sequential, it might be useful to not even have a resultset class at all. The connection could send the query and have some read function, like the usual read/write functions in Asio can operate on the same stream. Minor issues: - Maybe it's not clear from the examples, but why would the user need connection::handshake when connection::connection already does it? - Shouldn't `tcp_ssl_connection::connect` accept an EndpointSequence to be more like other Asio functions. - The names "tcp_ssl_prepared_statement", "tcp_ssl_<component>" are quite repetitive and verbose in the documentation. Maybe "tcp_ssl" could become a namespace? Isn't that what Asio does for the ssl related objects? Some names might be reduced if there's no alternative. For instance, "prepared_statement" might become "statement" since there's no "unprepared_statement". - Wouldn't some form of `statement::execute` with variadic args (different name perhaps) be a simpler alternative to `statement::execute(boost::mysql::make\_values(...))`. Or maybe statement::operator(), as Phil suggested. Or some `statement::execute_with(...)`. In the variadic args, the optional err/info can go into some specified positions, since they're not ambiguous with the field variant types. This is a little tricky but definitely useful, especially if suggestions of customization points are implemented in the future. ## Implementation > What is your evaluation of the implementation? I haven't analyzed the implementation very profoundly. I skimmed through the source code and couldn't find anything problematic. It would be useful if the experts could inspect the Asio composed ops more deeply. CMakeLists.txt: - I believe the CMakeLists.txt script is not in the format of other boost libraries in boost/libs so it won't work with the super-project as it is. - The example/CMakeLists.txt script refers to BOOST_MYSQL_INTEGRATION_TESTS. I don't think examples can be considered integration tests. Examples: - The examples are very nice. Especially the one with coroutines. They are also very limited. They are all about the same text queries, which shouldn't even be used in favor of prepared statements. - Many examples about continuation styles are not very useful because this is more of an Asio feature than a library feature. The library feature, so to speak, is supporting Asio tokens properly. The continuation styles could be exemplified in the exposition with some small snippets for users not used to Asio without the documentation losing any value. - Some examples are simple enough and don't require the reader to know the rest of the exposition. They are like a quick look into the library. These could come at the beginning, as in the Asio tutorials and Beast quick look section. - The first sync example could be simpler to involve just a hello world before moving on to other operations. - The page about the docker container should specify that the username and password are "root" and "". Tests: Some unit tests take a ***very*** long time. Enough to make coffee and a sandwich. And they seem to not be adding a lot of value in terms of coverage. For instance, "mysql/test/unit/detail/protocol/date.cpp(72): info: check '1974- 1-30' has passed" going through all possible dates multiple times took a long time. > Did you try to use the library? With what compiler? Did you have any problems? No problems at all. GCC 11 and MSVC 19. ## Documentation > What is your evaluation of the documentation? The documentation is complete. The main points that differentiate the library are - it's a complete rewrite of the protocol, - it's low-level and - it's based on Boost.Asio The documentation should emphasize these points as much as possible, especially the first one. This should be in the introduction, the motivation, slogans, logos, and wherever people can see it easily. The documentation should also provide arguments and evidence that these design goals are a good idea, as often discussed when the topic is the value of this library. Why is it worth rewriting the protocol? To what use cases are such a low-level library useful? Why should a person who already uses other libraries or the C API care about Asio now? Something that should also be highlighted is the difference between the library and other higher-level libraries, in particular, naming names. Minor issues: - There's no link in the documentation to the protocol specification. It would be interesting to know what the reference specification is. Or whether the protocol was inferred somehow. Is there any chance this protocol might change? What about divergences between MySql and MariaDB? How stable is the protocol? For what range of versions does it work? What's the policy when it changes? - Some links are broken (for instance, linking to https://anarthal.github.io/boost-mysql/index.html) - "All async operations in this library support per-operation cancellation". It's important to highlight this is per operation in the Asio sense of an operation but not in the MySql sense of an operation because the MySql connection is invalid after that. - "Boost.MySql has been tested with the following versions of MySQL". MariaDB is not a version of MySql. - Prepared statements should come first in the examples, to highlight them as the default pattern. - The documentation refers to topics that haven't been explained yet. Maybe "value" could be explained after "row", and "row" could be explained after "resultset" and "resultset" after "queries". - The section "Text Queries" is quite small in comparison to other sections. It could include some examples and snippets like other sections do. - "The following completion tokens can be used in any asyncrhonous operation within Boost.Mysql" -> "Any completion token..." - "When they fail, they throw a boost::system::system_error exception". Don't these functions just set the proper error_code, as usual with Asio and Beast? - The "MySQL to C++ mapping reference" section should be using a table. - A small subsection on transactions would be helpful even if there's no library functionality to help with that. - The documentation should include some comparisons that are not obvious to potential users. C/C++ APIs. The advantages of the Asio async model. Benchmarks if possible. ## Conclusion > How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? I spent one day in this review. I read all the documentation, ran the tests, experimented with the examples, and had a reasonable look at the implementation. > Are you knowledgeable about the problem domain? I'm reasonably educated about databases but not an expert. I've been working a lot with Asio. > Are there any immediate improvements that could be made after acceptance, if acceptance should happen? While it's important to have a general variant type for row values, a simpler interface for tuples of custom types would be very welcome and would simplify things by a lot, while also avoiding allocations, since columns always have the same types. This feature is too obvious since users almost always know their column types at compile time and this demand is too recurrent in applications to ignore. > Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. I believe it should be conditionally accepted with the same conditions stated in other reviews: allowing for memory reuse in the read_* functions and fixing the "value" type. Best, Em ter., 10 de mai. de 2022 ?s 04:14, Richard Hodges via Boost < boost(a)lists.boost.org> escreveu: > Dear All, > > The Boost formal review of the MySQL library starts Today, taking place > from May 10th, 2022 to May 19th, 2022 (inclusive) - We are starting one day > after the announced date and extending the period by one day to compensate. > > The library is authored by Rub?n P?rez Hidalgo (@anarthal in the CppLang > slack). > > Documentation: https://anarthal.github.io/mysql/index.html > Source: https://github.com/anarthal/mysql/ > > The library is built on the bedrock of Boost.Asio and provides both > synchronous and asynchronous client connectors for the MySQL database > system. > > Boost.MySQL is written from the ground up, implementing the entire protocol > with no external dependencies beyond the Boost library. > It is compatible with MariaDB. > > Connectivity options include TCP, SSL and Unix Sockets. > > For async interfaces, examples in the documentation demonstrate full > compatibility with all Asio completion handler styles, including: > > Callbacks:- > https://anarthal.github.io/mysql/mysql/examples/query_async_callbacks.html > > Futures :- > https://anarthal.github.io/mysql/mysql/examples/query_async_futures.html > > Boost.Coroutine :- > https://anarthal.github.io/mysql/mysql/examples/query_async_coroutines.html > > C++20 Coroutines :- > > https://anarthal.github.io/mysql/mysql/examples/query_async_coroutinescpp20… > > Rub?n has also implemented the Asio protocols for deducing default > completion token types :- > > https://anarthal.github.io/mysql/mysql/examples/default_completion_tokens.h… > > Reviewing a database connector in depth will require setting up an instance > of a MySQL database. Fortunately most (all?) Linux distributions carry a > MySQL and/or MariaDB package. MySQL community edition is available for > download on all platforms here: > https://dev.mysql.com/downloads/ > > Rub?n has spent quite some time in order to bring us this library > candidate. The development process has no doubt been a journey of discovery > into Asio, its concepts and inner workings. I am sure he has become a fount > of knowledge along the way. > > From a personal perspective, I was very happy to be asked to manage this > review. I hope it will be the first of many more reviews of libraries that > tackle business connectivity problems without further dependencies beyond > Boost, arguably one of the most trusted foundation libraries available. > > Please provide in your review information you think is valuable to > understand your choice to ACCEPT or REJECT including Describe as a > Boost library. Please be explicit about your decision (ACCEPT or REJECT). > > Some other questions you might want to consider answering: > > - Will the library bring additional out-of-the-box utility to Boost? > - What is your evaluation of the implementation? > - What is your evaluation of the documentation? > - Will the choice of API abstraction model ease the development of > software that must talk to a MySQL database? > - Are there any immediate improvements that could be made after > acceptance, if acceptance should happen? > - Did you try to use the library? With which compiler(s)? Did you > have any problems? > - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? > - Are you knowledgeable about the problem domain? > > More information about the Boost Formal Review Process can be found > at: http://www.boost.org/community/reviews.html > > The review is open to anyone who is prepared to put in the work of > evaluating and reviewing the library. Prior experience in contributing to > Boost reviews is not a requirement. > > Thank you for your efforts in the Boost community. They are very much > appreciated. > > Richard Hodges > - review manager of the proposed Boost.MySQL library > > Rub?n is often available on CppLang Slack and of course by email should you > require any clarification not covered by the documentation, as am I. > > -- > Richard Hodges > hodges.r(a)gmail.com > tg: @rhodges > office: +44 2032 898 513 > mobile: +376 380 212 > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > -- Alan Freitas https://github.com/alandefreitas ------------------------------ Subject: Digest Footer _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost ------------------------------ End of Boost Digest, Vol 6704, Issue 1 **************************************

6 8

The Future of C++ Modules
by Benedict Bede McNamara 13 May '22

13 May '22

On 5/13/22 5:24 AM, Peter Dimov via Boost wrote: >> John Maddock wrote: >> I'm afraid my conclusion is that modules are simply not yet ready for >> prime time. >> >> If they ever are. >> >> Modules can work for leaf libraries, but for libraries used as dependencies >> by other libraries, you'll encounter a situation where the same translation >> unit imports boost.lib or "boost/lib.hpp" in one place and then includes >> "boost/lib/something.hpp" in another, which is probably never going to >> work correctly. >This is sounds like how I thought it had to work to be effective. If I >understand this correctly, the whole modules concept is in fundamental >conflict with the anything which uses the boost inclusion/dependency >model - which is every module includes what it uses and nothing else. >In my view the whole modules idea is misconceived. One more nail in >coffin of C++ xx standard libraries. >It's time for use to seriously start moving on. >Robert Ramey You can’t be serious. I have used modules in I++ and they function perfectly. C++ was kind of dodgy with its use of the pre-processor. Modules re-establish C++ as being the predominant language of its time. It is C++ that ‘has moved on’ from where Boost is at present. Boost is running at least 2 years behind the standard and It risks becoming irrelevant if it remains there for much longer. Sent from Mail for Windows From: boost-request(a)lists.boost.org Sent: Saturday, 14 May 2022 8:19 AM To: boost(a)lists.boost.org Subject: Boost Digest, Vol 6704, Issue 5 Send Boost mailing list submissions to boost(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.boost.org/mailman/listinfo.cgi/boost or, via email, send a message with subject or body 'help' to boost-request(a)lists.boost.org You can reach the person managing the list at boost-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost digest..." The boost archives may be found at: http://lists.boost.org/Archives/boost/ Today's Topics: 1. Re: cstring_view (Peter Dimov) 2. Re: cstring_view (Marshall Clow) 3. Re: cstring_view (Peter Dimov) 4. Re: cstring_view (Marshall Clow) 5. Re: cstring_view (Peter Dimov) 6. Re: cstring_view (Rainer Deyke) 7. Re: cstring_view (David Bien) 8. Re: MySql review (Rainer Deyke) 9. Re: The Future of C++ and Boost - C++ Modules (Robert Ramey) 10. Re: The Future of C++ and Boost - C++ Modules (Peter Dimov) 11. Re: cstring_view (Marshall Clow) 12. Re: cstring_view (Peter Dimov) ---------------------------------------------------------------------- Message: 1 Date: Fri, 13 May 2022 21:09:47 +0300 From: "Peter Dimov" <pdimov(a)gmail.com> To: <boost(a)lists.boost.org> Subject: Re: [boost] cstring_view Message-ID: <01d201d866f4$a330d710$e9928530$(a)gmail.com> Content-Type: text/plain; charset="utf-8" David Bien wrote: > I guess when I read the impl I think to myself: What this is missing is a _length > member. But then it just becomes boost::string_view. > > What value added is there to this impl except that it is smaller than > boost::string_view due to lacking a _length member? Please see https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1402r0.pdf No idea why this particular implementation doesn't store the size. I would. ------------------------------ Message: 2 Date: Fri, 13 May 2022 11:14:13 -0700 From: Marshall Clow <mclow.lists(a)gmail.com> To: Boost Developers List <boost(a)lists.boost.org> Subject: Re: [boost] cstring_view Message-ID: <DFCD5BFF-F7CA-46CC-82DF-833CE68CB0F0(a)gmail.com> Content-Type: text/plain; charset=utf-8 On May 13, 2022, at 10:42 AM, David Bien via Boost <boost(a)lists.boost.org> wrote: > > I guess when I read the impl I think to myself: What this is missing is a _length member. But then it just becomes boost::string_view. > > What value added is there to this impl except that it is smaller than boost::string_view due to lacking a _length member? If you?re careful and don?t do much with it, it can hand you back a null terminated string. ? Marshall PS. I note that P1402 (the paper proposing cstring_view for the standard) was was reviewed by LEWG in 2019, and the resolution of that group was "We will not pursue P1402R0 or this problem space? ------------------------------ Message: 3 Date: Fri, 13 May 2022 21:18:24 +0300 From: "Peter Dimov" <pdimov(a)gmail.com> To: <boost(a)lists.boost.org> Subject: Re: [boost] cstring_view Message-ID: <01d301d866f5$d6cfe880$846fb980$(a)gmail.com> Content-Type: text/plain; charset="utf-8" Marshall Clow wrote: > On May 13, 2022, at 10:42 AM, David Bien via Boost <boost(a)lists.boost.org> > wrote: > > > > I guess when I read the impl I think to myself: What this is missing is a > _length member. But then it just becomes boost::string_view. > > > > What value added is there to this impl except that it is smaller than > boost::string_view due to lacking a _length member? > > If you?re careful and don?t do much with it, it can hand you back a null > terminated string. ??? In what scenarios will it not give you a null-terminated string? ------------------------------ Message: 4 Date: Fri, 13 May 2022 11:39:37 -0700 From: Marshall Clow <mclow.lists(a)gmail.com> To: Peter Dimov <pdimov(a)gmail.com> Cc: Boost Developers List <boost(a)lists.boost.org> Subject: Re: [boost] cstring_view Message-ID: <F5FB00FB-3576-47CF-8BEA-FFD90C2C74F0(a)gmail.com> Content-Type: text/plain; charset=utf-8 On May 13, 2022, at 11:18 AM, Peter Dimov via Boost <boost(a)lists.boost.org> wrote: > > Marshall Clow wrote: >> On May 13, 2022, at 10:42 AM, David Bien via Boost <boost(a)lists.boost.org> >> wrote: >>> >>> I guess when I read the impl I think to myself: What this is missing is a >> _length member. But then it just becomes boost::string_view. >>> >>> What value added is there to this impl except that it is smaller than >> boost::string_view due to lacking a _length member? >> >> If you?re careful and don?t do much with it, it can hand you back a null >> terminated string. > > ??? > > In what scenarios will it not give you a null-terminated string? char arr[6] = ?hello"; cstring_view csv(arr); assert(strlen(csv.data())) == 5); arr[5] = ?!?; assert(strlen(csv.data())) == 5); // boom ? Marshall PS. It promises to give you a null-terminated string, but has no way to actually guarantee that. ------------------------------ Message: 5 Date: Fri, 13 May 2022 21:57:39 +0300 From: "Peter Dimov" <pdimov(a)gmail.com> To: "'Marshall Clow'" <mclow.lists(a)gmail.com> Cc: "'Boost Developers List'" <boost(a)lists.boost.org> Subject: Re: [boost] cstring_view Message-ID: <01df01d866fb$52ff30f0$f8fd92d0$(a)gmail.com> Content-Type: text/plain; charset="utf-8" Marshall Clow wrote: > >> If you?re careful and don?t do much with it, it can hand you back a > >> null terminated string. > > > > ??? > > > > In what scenarios will it not give you a null-terminated string? > > char arr[6] = ?hello"; > cstring_view csv(arr); > assert(strlen(csv.data())) == 5); > arr[5] = ?!?; > assert(strlen(csv.data())) == 5); // boom The main use of cstring_view, like string_view, is as a parameter (and return) type. So if you have a function void f1( cstring_view csv ); it's true that if inside f1 you write to some random character this may invalidate csv's promise to be null-terminated, but I see little salient difference between this and void f2( char const* csv ); // pre: csv is null-terminated char seq where f2 writing to a carefully chosen char may also invalidate the precondition. Typing "cstring_view" is merely a different way of spelling out the "pre" of f2. Similarly, cstring_view g1(); is an alternative way of spelling char const* g2(); // post: the return value is a null-terminated char seq ------------------------------ Message: 6 Date: Fri, 13 May 2022 21:29:06 +0200 From: Rainer Deyke <rdeyke(a)gmail.com> To: boost(a)lists.boost.org Subject: Re: [boost] cstring_view Message-ID: <t5mbi2$42u$1(a)ciao.gmane.io> Content-Type: text/plain; charset=UTF-8; format=flowed On 13.05.22 20:39, Marshall Clow via Boost wrote: > On May 13, 2022, at 11:18 AM, Peter Dimov via Boost <boost(a)lists.boost.org> wrote: >> In what scenarios will it not give you a null-terminated string? > > char arr[6] = ?hello"; > cstring_view csv(arr); > assert(strlen(csv.data())) == 5); > arr[5] = ?!?; > assert(strlen(csv.data())) == 5); // boom > > ? Marshall > > PS. It promises to give you a null-terminated string, but has no way to actually guarantee that. That's an issue with views in general, not just cstring_view. std::string s = "hello"; string_view sv = s; assert(sv.size() == 5); s += "!"; assert(sv.size() == 5); // boom It is the responsibility of the creator of a view to ensure that the object being viewed does not change in a way that breaks the invariants of the view while the view is in use. -- Rainer Deyke (rainerd(a)eldwood.com) ------------------------------ Message: 7 Date: Fri, 13 May 2022 18:20:40 +0000 From: David Bien <davidbien(a)hotmail.com> To: "boost(a)lists.boost.org" <boost(a)lists.boost.org> Cc: Peter Dimov <pdimov(a)gmail.com> Subject: Re: [boost] cstring_view Message-ID: <MWHPR1801MB1934DE34D9E7AE1678101098B1CA9(a)MWHPR1801MB1934.namprd18.prod.outlook.com> Content-Type: text/plain; charset="Windows-1252" Exactly. But then it should just be called cstring_wrapper ? calling it cstring_view seems to impart qualities to it that it doesn?t have ? like I would assume that I could get a cstring_view that is a subview of an existing cstring_view for instance. Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows From: Peter Dimov via Boost<mailto:boost@lists.boost.org> Sent: Friday, May 13, 2022 12:19 PM To: boost(a)lists.boost.org<mailto:boost@lists.boost.org> Cc: Peter Dimov<mailto:pdimov@gmail.com> Subject: Re: [boost] cstring_view Marshall Clow wrote: > On May 13, 2022, at 10:42 AM, David Bien via Boost <boost(a)lists.boost.org> > wrote: > > > > I guess when I read the impl I think to myself: What this is missing is a > _length member. But then it just becomes boost::string_view. > > > > What value added is there to this impl except that it is smaller than > boost::string_view due to lacking a _length member? > > If you?re careful and don?t do much with it, it can hand you back a null > terminated string. ??? In what scenarios will it not give you a null-terminated string? _______________________________________________ Unsubscribe & other changes: https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.boos… ------------------------------ Message: 8 Date: Fri, 13 May 2022 21:37:36 +0200 From: Rainer Deyke <rdeyke(a)gmail.com> To: boost(a)lists.boost.org Subject: Re: [boost] MySql review Message-ID: <t5mc20$87r$1(a)ciao.gmane.io> Content-Type: text/plain; charset=UTF-8; format=flowed On 13.05.22 17:23, Phil Endecott via Boost wrote: > The aim should be "secure by default". Users are lazy. The > particular danger in this case is that they do an initial test with > the password in the source, and then move it somewhere secure later, > but the password is still exposed in their revision control history. > At this point in history, there is no excuse to repeat the mistakes > that have lead to really very serious security problems in the past. > Make the default mechanism, and the first one that you describe in > the docs, the most secure one. Looking for credentials in a file on disk may be more secure than embedding the credentials in code, but it is most definitely the most secure mechanism. The most secure mechanism is to always ask the user at program start-up. Or better yet, ask each time a connection is created, and then immediately wipe the credentials from RAM in order to mitigate RAM scanning attacks. -- Rainer Deyke (rainerd(a)eldwood.com) ------------------------------ Message: 9 Date: Fri, 13 May 2022 12:33:50 -0700 From: Robert Ramey <ramey(a)rrsd.com> To: Peter Dimov via Boost <boost(a)lists.boost.org> Subject: Re: [boost] The Future of C++ and Boost - C++ Modules Message-ID: <4134c080-20bb-16d2-ff81-0c6b6dc52d75(a)rrsd.com> Content-Type: text/plain; charset=UTF-8; format=flowed On 5/13/22 5:24 AM, Peter Dimov via Boost wrote: > John Maddock wrote: >> I'm afraid my conclusion is that modules are simply not yet ready for >> prime time. > > If they ever are. > > Modules can work for leaf libraries, but for libraries used as dependencies > by other libraries, you'll encounter a situation where the same translation > unit imports boost.lib or "boost/lib.hpp" in one place and then includes > "boost/lib/something.hpp" in another, which is probably never going to > work correctly. This is sounds like how I thought it had to work to be effective. If I understand this correctly, the whole modules concept is in fundamental conflict with the anything which uses the boost inclusion/dependency model - which is every module includes what it uses and nothing else. In my view the whole modules idea is misconceived. One more nail in coffin of C++ xx standard libraries. It's time for use to seriously start moving on. Robert Ramey ------------------------------ Message: 10 Date: Sat, 14 May 2022 00:16:26 +0300 From: "Peter Dimov" <pdimov(a)gmail.com> To: <boost(a)lists.boost.org> Subject: Re: [boost] The Future of C++ and Boost - C++ Modules Message-ID: <01f501d8670e$b57a64d0$206f2e70$(a)gmail.com> Content-Type: text/plain; charset="utf-8" Robert Ramey wrote: > On 5/13/22 5:24 AM, Peter Dimov via Boost wrote: > > John Maddock wrote: > > >> I'm afraid my conclusion is that modules are simply not yet ready for > >> prime time. > > > > If they ever are. > > > > Modules can work for leaf libraries, but for libraries used as > > dependencies by other libraries, you'll encounter a situation where > > the same translation unit imports boost.lib or "boost/lib.hpp" in one > > place and then includes "boost/lib/something.hpp" in another, which is > > probably never going to work correctly. > > This is sounds like how I thought it had to work to be effective. If I understand > this correctly, the whole modules concept is in fundamental conflict with the > anything which uses the boost inclusion/dependency model - which is every > module includes what it uses and nothing else. > > In my view the whole modules idea is misconceived. One more nail in coffin of > C++ xx standard libraries. > > It's time for use to seriously start moving on. Looks like I was mistaken, though. At least with header units, i.e. `import "boost/lib.hpp"`, it all seems to "just work" under MSVC. That is, the compiler automatically merges the identical definitions from the sub-#includes. ------------------------------ Message: 11 Date: Fri, 13 May 2022 15:16:19 -0700 From: Marshall Clow <mclow.lists(a)gmail.com> To: Boost Developers List <boost(a)lists.boost.org> Cc: Rainer Deyke <rdeyke(a)gmail.com> Subject: Re: [boost] cstring_view Message-ID: <3C70E2E0-DC7A-4263-9D93-FCD8220A39BE(a)gmail.com> Content-Type: text/plain; charset=utf-8 On May 13, 2022, at 12:29 PM, Rainer Deyke via Boost <boost(a)lists.boost.org> wrote: > > On 13.05.22 20:39, Marshall Clow via Boost wrote: >> On May 13, 2022, at 11:18 AM, Peter Dimov via Boost <boost(a)lists.boost.org> wrote: >>> In what scenarios will it not give you a null-terminated string? >> char arr[6] = ?hello"; >> cstring_view csv(arr); >> assert(strlen(csv.data())) == 5); >> arr[5] = ?!?; >> assert(strlen(csv.data())) == 5); // boom >> ? Marshall >> PS. It promises to give you a null-terminated string, but has no way to actually guarantee that. > > That's an issue with views in general, not just cstring_view. > > std::string s = "hello"; > string_view sv = s; > assert(sv.size() == 5); > s += "!"; > assert(sv.size() == 5); // boom I don?t see the problem here (and when I run the code I get no error - after adding the missing ?std::'). No assertion failure; no undefined behavior (unlike the cstring_view example) ? Marshall ------------------------------ Message: 12 Date: Sat, 14 May 2022 01:19:33 +0300 From: "Peter Dimov" <pdimov(a)gmail.com> To: <boost(a)lists.boost.org> Subject: Re: [boost] cstring_view Message-ID: <01fc01d86717$873b2a60$95b17f20$(a)gmail.com> Content-Type: text/plain; charset="utf-8" Marshall Clow wrote: > On May 13, 2022, at 12:29 PM, Rainer Deyke via Boost > <boost(a)lists.boost.org> wrote: > > > > On 13.05.22 20:39, Marshall Clow via Boost wrote: > >> On May 13, 2022, at 11:18 AM, Peter Dimov via Boost > <boost(a)lists.boost.org> wrote: > >>> In what scenarios will it not give you a null-terminated string? > >> char arr[6] = ?hello"; > >> cstring_view csv(arr); > >> assert(strlen(csv.data())) == 5); > >> arr[5] = ?!?; > >> assert(strlen(csv.data())) == 5); // boom ? Marshall PS. It > >> promises to give you a null-terminated string, but has no way to actually > guarantee that. > > > > That's an issue with views in general, not just cstring_view. > > > > std::string s = "hello"; > > string_view sv = s; > > assert(sv.size() == 5); > > s += "!"; > > assert(sv.size() == 5); // boom > > I don?t see the problem here (and when I run the code I get no error - after > adding the missing ?std::'). > > No assertion failure; no undefined behavior (unlike the cstring_view example) Only because "hello!" fits into the small buffer, I suspect. If `s` reallocates, `sv` would be left dangling. ------------------------------ Subject: Digest Footer _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost ------------------------------ End of Boost Digest, Vol 6704, Issue 5 **************************************

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Re: [boost] Review of Boost.MySql
by Ruben Perez 13 May '22

13 May '22

> > > > I was just imagining users concatenating queries. May be a misconception, > > yours is a legitimate use case. > > I've thought more about this, and I'm guessing you were thinking > about this XKCD https://xkcd.com/327/ SQL Injection. Yes, this was definitely what I was thinking of ;) > > The proper and ideal remedy is not the XKCD one though, > it is using prepared statements and binding values. > > The still proper but less ideal next remedy is a "safe" way to concatenate > user inputs into textual SQL. I.e. the equivalent of > SQLite: https://www.sqlite.org/printf.html with %q and %Q > PostgreSQL: https://www.postgresql.org/docs/current/libpq-exec.html#LIBPQ-PQESCAPELITER… > Since you want to avoid the MySQL client, which I suppose has this > too, you have to provide your own. Since not everything can be done with prepared statements (I've been shown some legitimate use cases that are not covered), I've raised https://github.com/anarthal/mysql/issues/69 to address this, and I will likely implement something like this. > > Third and finally, this XKCD hack indeed does only work is one can > execute several semi-colon separated statements. > So on second thought, it is *definitely* be a good thing to have > separate APIs, to execute single statement, as opposed from executing > "scripts" of statements, plural. With a single-statement API, *even* > the XKCD hack won't work, since it would yield an invalid single > statement. > This is what you had in mind IMHO :). The trouble with this is that multi-statement is not a separate protocol primitive, but rather something you turn on or off for the entire session. So your connections either support it or don't. If you include such a semicolon separated set of queries in your query request, and this capability is turned on, the server will happily execute it. So maybe this should be implemented as an extra value in connection_params (https://anarthal.github.io/mysql/mysql/connparams.html) with adequate security warnings.

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Re: [boost] Review of Boost.MySql
by Dominique Devienne 13 May '22

13 May '22

Meant to send this to the list, not just Ruben. Re-sending. --DD On Fri, May 13, 2022 at 11:59 AM Dominique Devienne <ddevienne(a)gmail.com> wrote: > > On Thu, May 12, 2022 at 9:02 PM Ruben Perez <rubenperez038(a)gmail.com> wrote: > > > > The server sends several resultsets after that. I haven't focused a lot on > > > > this because it sounded risky (in terms of security) for me. > > > > > > Not sure what's risky here. Maybe I'm missing something. > > > > I was just imagining users concatenating queries. May be a misconception, > > yours is a legitimate use case. > > I've thought more about this, and I'm guessing you were thinking > about this XKCD https://xkcd.com/327/ SQL Injection. > > The proper and ideal remedy is not the XKCD one though, > it is using prepared statements and binding values. > > The still proper but less ideal next remedy is a "safe" way to concatenate > user inputs into textual SQL. I.e. the equivalent of > SQLite: https://www.sqlite.org/printf.html with %q and %Q > PostgreSQL: https://www.postgresql.org/docs/current/libpq-exec.html#LIBPQ-PQESCAPELITER… > Since you want to avoid the MySQL client, which I suppose has this > too, you have to provide your own. > > Third and finally, this XKCD hack indeed does only work is one can > execute several semi-colon separated statements. > So on second thought, it is *definitely* be a good thing to have > separate APIs, to execute single statement, as opposed from executing > "scripts" of statements, plural. With a single-statement API, *even* > the XKCD hack won't work, since it would yield an invalid single > statement. > This is what you had in mind IMHO :). > > So the ability to execute multi-statement is important, especially in > my DDL use-case, > but it should be a separate API from the more regular single-statement > APIs, and come > with extra warnings in the document about such SQL injections (with > obligatory link to XKCD ;) > > PS: Fourth, the XKCD hack is possible only of the SQL is executed as > the owner of the schema, > or a DBA/Superuser, which is of course a mistake and a big no-no, > yet all too common... > Users of the DB, including mid-tier services, should NOT have DDL > privileges on the schema and its objects. > Change the DROP into a DELETE, and that's still nasty, but then you > use ROLEs to restrict some DMLs, > and possibly also RLS (Row Level Security) for finer-grained > authorization. But we are getting off-topic :)

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Future of C++ and Boost
by Vinnie Falco 13 May '22

13 May '22

It might be interesting to think about where C++ and Boost will be in the next 20 years and in the next 50 years. There has been an explosion of research and development into new programming languages (Rust being the most visible example). C++ is hardly the most popular language (Python is, if the TIOBE index is to be believed). But C++ is an essential language because it occupies the unique position of being as close as possible to assembly language while remaining high level. The zero-cost abstractions, metaprogramming, and powerful compositional tools of C++ still have no competitors and they are unlikely to have them any time soon. This doesn't necessarily mean that C++ is good for everything; there's an opportunity cost for all this. C++ code is generally more complex, harder to read, and harder to write than other code. Other languages are much better suited for certain tasks. No one should be implementing a content-driven website using Asio and Beast for example. But for the things that C++ is good at, it excels at them. A recent reddit post [1] provided a decent list:: * games * databases * high frequency trading * search (Google/Bing/DuckDuckGo) * web browsers (Chrome/Safari/Edge) * virtual reality headsets (Facebook) * distributed systems at big tech companies (Google/Microsoft/Facebook) * low level libraries (machine learning libraries like tensorflow and pytorch) * compilers, virtual machines, interpreters (JVM/gcc/LLVM) * robotics & hardware (ex: self driving cars, planes, missiles, space ships, etc) My opinion is that wg21 (the C++ standards committee) has been growing increasingly out of touch with the needs of the larger C++ community. Not necessarily out of malice, but because the bureaucratic process of the committee does not align the incentives of its members with users. I predict that we will see the C++ standard library become increasingly irrelevant by not only failing to produce stable things that people want, but also by not even keeping up feature-wise with the library ecosystem of other languages. Where is Requests [2] for C++? Python has had this for over a decade. In case you think I'm exaggerating, look at this comment from Reddit: ...a major vendor is getting ready to release a product that does not allow user applications to directly access TCP sockets so the only way to get any network access is to go through their standard library which only supports backdoored HTTPS. This vendor of course is Apple, as can be seen in P1860R0 [4]. We should not expect that wg21 will be able to deliver an important feature such as networking in a form that will be usable or recognizable to non-committee members. What does this mean for C++ and Boost? I believe there is a significant opportunity for Boost to step in and become the rational collection of actually useful libraries that the C++ standard library is not. We already have networking, some protocols, and JSON. We (the existing Boost authors and contributors) might consider looking to the list above of industries that use C++, and focus our efforts more towards providing libraries that enhance those industries. Perhaps by reaching out to leaders in those fields we might establish working relationships and build, say, the next Boost.Tensorflow or something like that. I don't know. Oh, and add "cryptocurrency" to the list above. C++ is the language of blockchain, because performance matters. What do you think? Thanks Vinnie [1] <https://www.reddit.com/r/cpp/comments/u5vjni/comment/i54qbzq> [2] <https://docs.python-requests.org/en/latest/> [3] <https://www.reddit.com/r/cpp/comments/u6z8gr/comment/i5caxr6> [4] <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1860r0.html>

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Re: [boost] Review of Boost.MySql
by Ruben Perez 12 May '22

12 May '22

> Indeed. But even your imagined batch interface only works well for > queries/selects, > while for inserts (or updates), the client does not need to just send > a small textual > SQL query, but potentially a bunch of data for the rows too. A true > pipeline allows > sending the rows for a second insert while the first insert is being processed. It would work for inserts too, as values are either part of the query string or part of the statement execute packet. In both cases, part of the request. > Such a mode may be useful for schema creation OTOH. We have large schemas, > with hundreds of tables, indexes, triggers, etc... Done from C++ code > client-side, > not via a DBA manually executing on the server using SQL files and the > native CLI. > For that use-case, the ability to send many DDLs in a single batch > would definitely > save on the round-trips to the server. We try hard to minimize roundtrips! Thanks for sharing this use case, I definitely wasn't aware of it and seems a reason towards implementing multi-statement. > You don't need to necessarily use Google's protobufs library. > There's https://github.com/mapbox/protozero for example, and similarly, a > from-scratch implementation to just encode-decode a specific protocol > can also be written. I wasn't aware of this.Thanks. > > The server sends several resultsets after that. I haven't focused a lot on > > this because it sounded risky (in terms of security) for me. > > Not sure what's risky here. Maybe I'm missing something. I was just imagining users concatenating queries. May be a misconception, yours is a legitimate use case. > Note that PostgreSQL's COPY is not file-specific, and a first-class citizen > at the protocol level, depending on a pure binary format (with text mode too). > I use COPY with STDIN / STDOUT "files", i.e. I prepare memory buffers and > send them; and read memory buffers, and decode them. No files involved. Unfortunately, that does not seem to be the case for MySQL. You issue the LOAD DATA statement via a regular query packet, and the server returns you another packet with the file path it wants. You then read it in the client and send it to the server in another packet. I've made it work with CSV files, and I'd say it's the only format allowed, AFAIK. > Maybe our use-case of very large data (with large blobs), *and* very > numerous smaller data, > that's often loaded en-masse, by scientific desktop applications, and > increasingly mid-tier services > for web-apps, is different from the more common ecommerce web-app > use-case of many people. It is good to hear different use cases than the regular web server we all have in mind. It will help me during further development. > > When I evaluate DB performance, I tend to concentrate on "IO" performance, > in terms of throughput and latency, independent of the speed of the > SQL engine itself. > There's nothing I can do about the latter, while the way one uses the Client API > (or underlying protocol features) is under my control. So I do mostly > INSERTs and > SELECTs, with and without WHERE clauses (no complex JOINs, CTEs, etc...). > > Because we are in the scientific space, we care about both many small rows > (millions, of a few bytes to KBs each at most), and a few (hundreds / thousands) > much larger rows with blobs (with MBs to GBs sizes). The truly large > "blobs" (files) are > kept outside the DB, since mostly read only (in the GBs to TBs sizes each, that > can accumulate to 2.6 PB for all a client's data I heard just > yesterday for example). > > I'll also compare inserting rows 1-by-1, with and without prepared statements, > to inserting multi-rows per-statement (10, 100, 1000 at a time), to the "bulk" > interface (COPY for PostgreSQL, LOCAL for MySQL, Direct-Path load in OCI). > For example with SQLite: > https://sqlite.org/forum/forumpost/baf9c444d9a38ca6e59452c1c568044aaad50bba… > (SQLite as no "bulk" interface, doesn't need one, since "embedded" > thus "zero-latency") > > For PostgreSQL, we also compared text vs binary modes (for binds and > resultsets). > > For blobs, throughput of reading and writing large blobs, whole and in-part, > with different access patterns, like continuous ranges, or scattered inside). > > A very important use-case for us, for minimizing round-trips, is how > to load a subset of rows, > given a list of primary keys (typically a surrogate key, like an > integer or a uuid). For that, > we bind a single array-typed value for the WHERE clause's placeholder > to the query, > and read the resultset, selecting 1%, 5%, 10%, etc... of the rows from > the whole table. > (selecting each row individually, even with a prepared query, is terribly slow). Thanks for sharing. It will definitely help me during benchmarking. Regards, Ruben.

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Mixing C++ language versions
by Kenneth Porter 12 May '22

12 May '22

Can one mix compilation units or libraries built with different versions of C++? If I build my DLL with C++20, can a customer use it with their C++11 app? How are compiler and library vendors dealing with this? Do/will they supply multiple binaries for each C++ version? (I'm already building for each architecture plus release/debug. Adding the compiler version explodes the number of binaries to build and test.)

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Re: [boost] Mixing C++ language versions
by Glen Fernandes 12 May '22

12 May '22

On Thu, May 12, 2022 at 6:52 AM Kenneth Porter via Boost <boost(a)lists.boost.org> wrote: > > Do/will they supply multiple binaries for each C++ version? (I'm already building for > each architecture plus release/debug. Adding the compiler version explodes > the number of binaries to build and test.) The variants you have so far are: - Architecture - Release or Debug I've known library vendors to even have the following variants: - Architecture - Release or Debug - C++ standard version - Static or dynamic linking with the C++ runtime library - Single or multi threaded versions of the C++ runtime library (at one point in time) Shipping library sources to your users (instead of binaries) might be easier. Glen

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[filesystem] create_directories fails on exFat formatted disk under Windows
by Chris Trueman 12 May '22

12 May '22

Using an exFat formatted disk with Windows. Start with a path: e:\tmp Call filesystem::create_directories("e:\\tmp\\boost") This should succeed, creating the boost folder in e:\tmp. It fails with boost 1.79.0. It tries to create e:\tmp which already exists. In boost 1.78.0 this works as expected. I believe the root cause is the change to status(...). It calls detail::symlink_status(...) which calls GetFileInformationByHandleEx which (at least for the params used in filesystem) doesn't work on exFat formatted disks. Chris.

2 2

SOCKS-Asio library
by Alan de Freitas 11 May '22

11 May '22

Hi, everyone! I've been writing this library for SOCKS4/5 based on Asio. The library is very embryonic but there's enough to connect to proxy servers and relay messages. I could really use some negative feedback. If anyone would like to give it a try, here are the links: Repo: https://github.com/alandefreitas/socks_proto Docs: https://develop.socks-proto.cpp.al/ #boost-socks on Slack Thanks! -- Alan Freitas https://github.com/alandefreitas

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Re: [boost] Boost Digest, Vol 6699, Issue 1
by Benedict Bede McNamara 08 May '22

08 May '22

You need modules urgently. Sent from Mail for Windows From: boost-request(a)lists.boost.org Sent: Sunday, 8 May 2022 10:00 PM To: boost(a)lists.boost.org Subject: Boost Digest, Vol 6699, Issue 1 Send Boost mailing list submissions to boost(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.boost.org/mailman/listinfo.cgi/boost or, via email, send a message with subject or body 'help' to boost-request(a)lists.boost.org You can reach the person managing the list at boost-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost digest..." The boost archives may be found at: http://lists.boost.org/Archives/boost/ Today's Topics: 1. Re: Any objections to making C++14 the current baseline for Boost support and testing? (Seth) 2. Re: Any objections to making C++14 the current baseline for Boost support and testing? (Christopher Kormanyos) 3. Re: Any objections to making C++14 the current baseline for Boost support and testing? (Bo Persson) ---------------------------------------------------------------------- Message: 1 Date: Sat, 07 May 2022 15:30:08 +0200 From: Seth <bugs(a)sehe.nl> To: "Boost List" <boost(a)lists.boost.org> Subject: Re: [boost] Any objections to making C++14 the current baseline for Boost support and testing? Message-ID: <e76334c1-625a-4ee2-999f-75959822562b(a)www.fastmail.com> Content-Type: text/plain > Even though 14 has lotsof bug fixes, > the only real key advanced featureis relaxed constexpr constraints > anddigit separators. I'd say that polymorphic lambdas, lambda capture initializers, return type deduction, decltype(auto) are all more important and really felt. I can live without the library features (because they're easy to provide, except the UDLs) ------------------------------ Message: 2 Date: Sun, 8 May 2022 09:31:19 +0000 (UTC) From: Christopher Kormanyos <e_float(a)yahoo.com> To: Boost List <boost(a)lists.boost.org> Subject: Re: [boost] Any objections to making C++14 the current baseline for Boost support and testing? Message-ID: <1679327021.415697.1652002279472(a)mail.yahoo.com> Content-Type: text/plain; charset=UTF-8 >> Even though 14 has lotsof bug fixes, >> the only real key advanced featureis>> relaxed constexpr constraints >> and digit separators. I apologize for my perhaps unwisely chosen(or even wrong) wording. > I'd say that polymorphic lambdas, lambda> capture initializers, return type deduction,> decltype(auto) are all more important> and really felt. ... And I do respect this comment. But I'm not quite ready to give upon eleven just yet... Let's argue the controversial C++11/14baseline issue from a purely service-oriented,product-management point of view. Boost has a deep symbiosis with C++11and vice-versa. There are clients usingBoost with C++11. To drop C++11 from a product/servicepoint of view should only be allowed ifa viable option is provided --- freelyand easily obtained --- for those clientsusing Boost with C++11. So I would say, prove to the clients,prove to ourselves what this optionactually is. Which option will allowclients stuck on C++11 (maybe notby choice) to continue to use Boostwithout C++11 support? One possibility comes to mind:Freeze at 1.80 if you need C++11,but I don't like this option. Kind regards, Chris On Saturday, May 7, 2022, 03:36:26 PM GMT+2, Seth via Boost <boost(a)lists.boost.org> wrote: > Even though 14 has lotsof bug fixes, > the only real key advanced featureis relaxed constexpr constraints > anddigit separators. I'd say that polymorphic lambdas, lambda capture initializers, return type deduction, decltype(auto) are all more important and really felt. I can live without the library features (because they're easy to provide, except the UDLs) _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost ------------------------------ Message: 3 Date: Sun, 8 May 2022 12:37:00 +0200 From: Bo Persson <bo(a)bo-persson.se> To: boost(a)lists.boost.org Subject: Re: [boost] Any objections to making C++14 the current baseline for Boost support and testing? Message-ID: <t586gu$cfq$1(a)ciao.gmane.io> Content-Type: text/plain; charset=UTF-8; format=flowed On 2022-05-08 at 11:31, Christopher Kormanyos via Boost wrote: > >> Even though 14 has lotsof bug fixes, >> the only real key advanced featureis>> relaxed constexpr constraints >> and digit separators. > I apologize for my perhaps unwisely chosen(or even wrong) wording. > >> I'd say that polymorphic lambdas, lambda> capture initializers, return type deduction,> decltype(auto) are all more important> and really felt. > ... And I do respect this comment. > But I'm not quite ready to give upon eleven just yet... > > Let's argue the controversial C++11/14baseline issue from a purely service-oriented,product-management point of view. > Boost has a deep symbiosis with C++11and vice-versa. There are clients usingBoost with C++11. > To drop C++11 from a product/servicepoint of view should only be allowed ifa viable option is provided --- freelyand easily obtained --- for those clientsusing Boost with C++11. > So I would say, prove to the clients,prove to ourselves what this optionactually is. Which option will allowclients stuck on C++11 (maybe notby choice) to continue to use Boostwithout C++11 support? It can also be argued that we might do some clients a disservice instead of a service. If the new features are *that* useful for the library authors, would they not be equally useful for the clients' code? By supporting old compilers and standards we let them procrastinate for another couple of years. Is that good? Or should we encourage them to move on? Perhaps a gentle push is all they need? "New and improved" is often used in product-marketing. Why not here? > One possibility comes to mind:Freeze at 1.80 if you need C++11,but I don't like this option. > > Kind regards, Chris > > ------------------------------ Subject: Digest Footer _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost ------------------------------ End of Boost Digest, Vol 6699, Issue 1 **************************************

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Copy_File Method Question
by Sean B 06 May '22

06 May '22

Good afternoon, Thank you for allowing me to join the group as I a newbie to the boost c++ libraries. My question I have to the development group is based on the copy_file method. Does the copy_file do a 'bit to bit' copy using (check sums and hash) or the original file? Thanks for any information on this.

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C++ package managers
by Adam Getchell 06 May '22

06 May '22

For what it’s worth, having tried Biicode (Conan’s predecessor), Conan, Spack, Conda, and vcpkg, vcpkg is the only package manager for which I’ve been able to consistently (i.e. since I started using it a few years ago) build combinations of {macOS, Linux, Windows } x { gcc, clang, msvc}. As my research project includes CGAL which includes Boost, Eigen, and TBB, that ends up being 100+ libraries. Manifest mode just works, and vcpkg artifacts looks promising: https://devblogs.microsoft.com/cppblog/vcpkg-artifacts/ -- Adam Getchell acgetchell(a)ucdavis.edu https://adamgetchell.org

2 2

Boost Community Maintenance Team Repository List
by James E. King III 28 Apr '22

28 Apr '22

Is the list of current CMT repositories accurate? I have been updating them with the latest GitHub Actions + Appveyor builds: https://svn.boost.org/trac10/wiki/CommunityMaintenance For reference, I maintain a spreadsheet on the current CI state of the CMT repositories as well as others I maintain and some I have assisted with - specifically to track their CI status: https://docs.google.com/spreadsheets/d/1aFdTMdJmmD9L5IyvJx-nj3BrMVztmlNo8Qw… Thanks, Jim

3 4

[dynamic_bitset] commit review - assist
by James E. King III 27 Apr '22

27 Apr '22

I could use some additional eyes on a few commits from a new submitter, if anyone wants to take a look. Hopefully I am going down the right path in my pedanticism. Thanks, - Jim

2 1

[release] Boost 1.79.0
by Marshall Clow 26 Apr '22

26 Apr '22

Release 1.79.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains numerous enhancements and bug fixes for existing libraries. For details, including download links, see <http://www.boost.org/users/news/version_1.79.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.79.0/> To install this release on your system, see <http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. -- The Boost Release Team Marshall Clow, Michael Caisse, Glen Fernandes

9 17

Cross-compile for Apple Silicon on an x86 Mac
by Ian Emmons 26 Apr '22

26 Apr '22

I am trying to build Boost 1.79.0 shared libraries on an x86-based Mac running the latest MacOS (Monterey, 12.3.1) using the latest Xcode (13.3.1, with Apple’s clang 13.1.6). Everything works great for building shared libraries that run on an x86-based Mac. My ideal would be to build a single set of universal (a.k.a. “fat”) binaries that include both x86 and ARM code, but Boost.Build does not seem to contain an option to do that. (Such options existed in the past for Intel/PowerPC combinations and then later for 64-bit/32-bit Intel combinations.) Second best is to build two sets of binaries, one for x86 and another for ARM. I tried to do this using the option architecture=x86,arm on the b2 command line, and it does in fact build two sets of binaries with the expected file names. For instance, for filesystem it builds these two: libboost_filesystem-clang-darwin13-mt-a64-1_79.dylib libboost_filesystem-clang-darwin13-mt-x64-1_79.dylib But when I use the “file” command to inspect the types of these files, they both are reported as "Mach-O 64-bit dynamically linked shared library x86_64”. Am I doing something wrong, here? Or is there a bug in Boost.Build regarding cross-compiling? Thanks, Ian

3 2

Re: [boost] JSON parser error handling
by Vinnie Falco 26 Apr '22

26 Apr '22

On Mon, Apr 25, 2022 at 1:55 PM Kenneth Porter via Boost <boost(a)lists.boost.org> wrote: > I don't see any information on where in the source string the > parse error happened so I have to set a breakpoint in my tag_invoke > functions to figure out where the syntax errors lie. You have two potentially throwing lines: boost::json::value jv = boost::json::parse(contents); and axes = boost::json::value_to<std::vector<AxisProperties> If your exception is coming from the call to parse() and you want to know where in the string you are, then you need to change your code to create an instance of json::parser and call parser::write or parser::write_some to feed in the input. These functions return the number of characters consumed, which will be less than the amount passed in if an error occurs. In this case, the number of characters parsed successfully can be used to calculate an offset into the input buffer to determine where the syntax error happened. If your exception is coming from the call to value_to<>(), things are not so simple. The original JSON string is no longer available, and information about which json::value came from what part of the string is not stored (that would slow down the library and take up unnecessary memory). The best you can do in this case is to set up BOOST_THROW_EXCEPTION to get a breakpoint at the moment an exception is thrown, and then use a debugger to inspect the state of the program. You can also attach source file and line number information to exceptions when they are thrown (the library already does this). Boost.JSON throws all exceptions from these functions; alternatively, you could set a breakpoint in each of them to inspect the state of the program when an error is encountered: <https://github.com/boostorg/json/blob/83c364afaf31b58cfe8b97ab159c406c508f4…> Thanks

2 1

JSON parser error handling
by Kenneth Porter 25 Apr '22

25 Apr '22

I'm using Boost.JSON to load some static data into a tree of structures. The parser throws exceptions on parse errors, and I print the std::exception::what() string. (I throw them up in a messagebox in my GUI.) I see things like "not a number" when parsing a string where a number was expected. But I don't see any information on where in the source string the parse error happened so I have to set a breakpoint in my tag_invoke functions to figure out where the syntax errors lie. Is there some way to get the library to report the offset in the source string to where the parse error happens as part of the exception? Here's my top-level invocation: #include <fstream> #include <stdexcept> #define BOOST_DLL_USE_STD_FS 1 // tell program_location to return a std::filesystem::path #include <boost/dll/runtime_symbol_info.hpp> // program_location #include <boost/json/src.hpp> // header-only implementation std::ifstream is(boost::dll::program_location().replace_extension("json")); std::string contents; contents.assign(std::istreambuf_iterator<char>(is), std::istreambuf_iterator<char>()); boost::json::value jv = boost::json::parse(contents); axes = boost::json::value_to<std::vector<AxisProperties> >(jv.as_object().at("axis")); Library source and background: <https://github.com/boostorg/json>

1 0

[dynamic_bitset] Add at(size_type) & Support unsiged long long since C++11.
by Nya Nya 23 Apr '22

23 Apr '22

I would like to add two member functions, `at(size_type)` and `to_ullong()`, and since C++11, the constructor is promoted from `unsigned long` to `unsigned long long`. 1. at(size_type) I think it's necessary to have a member function that does bounds checking and throws exceptions. 2. dynamic_bitset(size_type, unsigned long long, const Allocator&) & to_ullong() The constructor of std::bitset is unsigned long long since C++11, and a new member function `to_ullong()` has also been added. I know this library needs to be compatible with C++03, but I think it can be solved with the macro `BOOST_NO_LONG_LONG`. Now I have submitted a pull request for the member function `at(size_type)`. If allowed, I will submit a pull request for unsigned long long later. Thanks!

1 0

Boost.URL Proposal
by Alan de Freitas 20 Apr '22

20 Apr '22

Hi, again! Now that the Boost 1.79 has shipped, I'm just passing by to remind you folks that Vinnie and I are looking for a review manager for the library that we hope will become Boost.URL. As usual, we are available to answer questions about the library on the list, on the GitHub repository page <https://github.com/CPPAlliance/url>, via email <alandefreitas(a)gmail.com>, or on Slack (in #boost-url). Thanks, -- Alan Freitas https://github.com/alandefreitas

3 5

Build Boost Back Better
by Vinnie Falco 20 Apr '22

20 Apr '22

Well, now that I have everyone's attention just before the release, I'd like to draw attention to the elephant in the room. That is, the declining level of activity on the Boost mailing lists and the declining level of participation in the Boost formal review process. Both in terms of the number of reviewers, and in terms of the difficulty in finding a review manager. Clearly, a website update is necessary and along with it some type of campaign to highlight once again the important role that Boost serves in the C++ community for both professionals and amateurs alike. But what more can we do? This came up before but it is worth mentioning again; in addition to a website update to make boost.org modern and relevant, how do we feel about a transition to forum-based discussion instead of the mailing list? I realize this will ruffle some feathers but surely the alternative, a descent into irrelevance due to steady declining activity is worse? Discuss. -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

29 68

Changes in buildable components over time
by Tim Haines 19 Apr '22

19 Apr '22

I've recently needed to understand which components need to be built, which are header-only, and what versions correspond to each component (i.e., when was it introduced, when was it removed). Combining the outputs from 'bootstrap.sh --show-libraries' since 1.39.0 and scraping the library listings on the website as of 1.78.0, I was able to identify everything I needed. Surprisingly, though, it appears that coroutine2 and metaparse started out as buildable components, but then switched to being header-only. coroutine2 - introduced in 1.59.0 - first buildable in 1.59.0 - last buildable in 1.64.0 - available as of 1.78.0 metaparse - introduced in 1.61.0 - first buildable in 1.61.0 - last buildable in 1.65.1 - available as of 1.78.0 I cross-referenced the release notes, but I didn't see any mention of these components being made header-only. Is this intended behavior? Thanks. - Tim

2 3

New Boost Website: Open to Volunteers!
by Vinnie Falco 19 Apr '22

19 Apr '22

The C++ Alliance is putting together a working prototype of a new website to replace what is currently at boost.org. We could use help with exposition on most of the new pages. And feedback could be helpful to refine some of the interfaces and layouts. If there is consensus and the site replaces boost.org, there will be at least one or more revisions. So it is not necessary to get everything "perfect" on the first pass (or else it will never be finished). Note that this is not a design-by-committee project. There are specific goals that are thought essential to refresh the foundations of Boost's social technology. For example, we are building a forum as the primary means of message-based interaction. However we are also building a connector so that users who want to use a mailing-list style interface can continue to do so with no interruption of service. If you would like to participate in the process of building this site then feel free to subscribe to this new mailing list: <https://lists.boost.org/mailman/listinfo.cgi/boost-www> Thanks Vinnie

9 23

Does Anyone Need Help?
by Vinnie Falco 19 Apr '22

19 Apr '22

The C++ Alliance is receiving many applications with qualified C++ candidates, but we are having a hard time matching them up with long-term projects which are aligned with our organization's goals. Is there a list of libraries that need help or does anyone know of one or more particular libraries that are in need of improvement and work? -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

8 13

ignore_unused
by Vinnie Falco 18 Apr '22

18 Apr '22

Isn't it better to just write (void) x; instead of including a whole header file: #include <boost/core/ignore_unused> just to write boost::ignore_unused( x ); ? -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

4 3

Is there a design reason why beast static_string uses size_t for length?
by Ivan Matek 16 Apr '22

16 Apr '22

Internally as a member, not talking about template argument. I would naively assume that performance overhead of having conversion from uint8_t/uint16_t(and uint32_t if you want to allow "insanely" large static_strings) to size_t is not big enough to justify "large"(in context of microoptimizations for space) overhead due to alignment and size requirements of size_t(on 64b machines). Recently I other context I complained that there is no way to nicely embed godbolt/source examples in here :), so here is a link with example: https://godbolt.org/z/Y4Y5zKj86 regards, Ivan

3 4

Boost.Text is looking for a (mini-)review manager
by Mateusz Loskot 15 Apr '22

15 Apr '22

Hi, A reminder from the review wizards: The Boost.Text library developed by Zach Laine is still looking for a (mini-)review manager, see details at: https://lists.boost.org/Archives/boost//2020/08/249594.php and https://www.boost.org/community/review_schedule.html Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

2 3

MySQL library scheduled for review
by Mateusz Loskot 15 Apr '22

15 Apr '22

Hi, A brief announcement from the review wizards: Following the proposal [1] and search for the review manager, formal review of the MySQL library [2] has been scheduled to take place between May 9, 2022 - May 18, 2022. Details and links available here https://www.boost.org/community/review_schedule.html We'd like to thank Richard Hodges for volunteering to act as the review manager, again! [1] https://lists.boost.org/Archives/boost/2022/03/252584.php [2] https://github.com/anarthal/mysql/ Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 0

[release] Master branch is now open for merging
by Glen Fernandes 14 Apr '22

14 Apr '22

Master is open again, with no restrictions. Next milestone: June 22, Boost 1.80.0 closed for new libraries and breaking changes Release calendar: https://boost.org/development Glen

1 0

[release] Boost 1.7.0 beta 1 released
by Marshall Clow 13 Apr '22

13 Apr '22

Boost release 1.77.0 beta 1 is now available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.78.0.beta1/source/> The SHA256 checksums are as follows: 7a3a025451dfa2923129214eef7d16b03c02310a353d02158a549f6caa4284b0 boost_1_78_0_b1.tar.bz2 c491b1dcb916195598aa6581d6708d57fcc750516641c22511c088d572de9c07 boost_1_78_0_b1.tar.gz 35e7a3b0eb412a3933e57c72ba96374eb7d88ff1f89dbec62a16d67ffea2105a boost_1_78_0_b1.7z e6b68feb2f63401c96ca9fe25e939b409189fbe526a6e784e4bd69832c8f09cb boost_1_78_0_b1.zip For details of what's in the release, see <https://www.boost.org/users/history/version_1_78_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

2 1

Is Boost interested in a Redis client library?
by Marcelo Zimbres Silva 13 Apr '22

13 Apr '22

Hi, I am the author of Aedis, a Redis client library built on top of Boost.Asio that provides communication with the Redis Server over its native and most recent protocol RESP3 [1]. It is an implementation from scratch that depends only on other Boost Libraries (Asio, Variant2, Optional, etc.) and targets C++14. I would like to propose it for inclusion in Boost in the near future if there is enough interest, at the moment I am interested in early feedback as I finish writing it (writing docs, improving tests etc.) - Do you think this library would be valuable to Boost? - Was the documentation helpful to understand what Aedis provides? - Does the design look good? - Any feedback is welcome. Link to Aedis Documentation: https://mzimbres.github.io/aedis/ Link to the github project: https://github.com/mzimbres/aedis If you never heard about Redis, this is the best place to start: https://redis.io Regards, Marcelo [1] https://github.com/antirez/RESP3/blob/master/spec.md

6 17

Proposing a MySQL client library for inclusion in Boost
by Ruben Perez 08 Apr '22

08 Apr '22

Hi all, I would like to propose my MySQL client library for inclusion in Boost. The library features asynchronous communication with MySQL and MariaDB servers, allowing the user to use txt queries and prepared statements. The library is based on Boost.Asio and follows its asynchronous model (in a similar way Boost.Beast does). The library is specific to MySQL and MariaDB systems, and is not intended as a SQL framework or ORM. It fits use cases like HTTP servers (possibly already using Beast), ETL pipelines or any other application that needs to access a MySQL database and wants to benefit from Asio's asynchrony. Please note that the library is a full implementation of MySQL wire protocol and does not use libmysqlclient under the hood. I'm looking for people who officially endorse the library. You can see the code in this GitHub repository <https://github.com/anarthal/mysql>, and the documentation is here <https://anarthal.github.io/mysql/index.html>. Many thanks, Ruben.

4 11

[release] Boost 1.79.0 Release Candidate 1 is available
by Marshall Clow 08 Apr '22

08 Apr '22

https://boostorg.jfrog.io/artifactory/main/release/1.79.0/source/ The first release candidates for the 1.79.0 release are now available at: <https://boostorg.jfrog.io/artifactory/main/release/1.79.0/source/> The SHA256 checksums are as follows: 3634f9a85759311f321e587eace21799c0d0c946ff933e477a2f98885c54bbff0 boost_1_79_0_rc1.zip 273f1be93238a068aba4f9735a4a2b003019af067b9c183ed227780b8f36062c boost_1_79_0_rc1.tar.gz 475d589d51a7f8b3ba2ba4eda022b170e562ca3b760ee922c146b6c65856ef39 boost_1_79_0_rc1.tar.bz2 6c97cf4f4a0eb00ed776c88065ab3f59e183fa5e65f6464ff94f92328352d9d6 boost_1_79_0_rc1.7z As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

5 6

Master branch now closed for 1.79.0 release
by Marshall Clow 07 Apr '22

07 Apr '22

Please do not make any commits to the master branch. — Marshall

1 0

Time delay Issue with async_write_some and async_read_some
by Daggumati, Rajesh 07 Apr '22

07 Apr '22

Hi Team, We can see two different behaviours in communication when we tested in windows and Linux with same hardware .Windows responded slowly compared to Linux. We are using async_write_some and async_read_some methods from boost library for RS-232 communication with hardware(COM1). m_serialPort.async_write_some(boost::asio::buffer(toSend), boost::bind(&SerialPortAsync::HandleSentData, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); m_serialPort.async_read_some(boost::asio::buffer(m_RecvBuffer), boost::bind(&SerialPortAsync::HandleReceive, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); Comparison Linux Vs Windows for same application : Linux Sending Time ---> 2020/11/23 17:34:56.678585,1064, , <-- (+0.000151) (11)[010B0557,0D0001E8,03C40F] [tx-queue:24] Send Receiving Time ---> 2020/11/23 17:34:56.680490,1064, , --> (+0.001905) (8)[060B0557,040D00E8] [tx-queue:24] Turnaround time : 0.001905 Windows Sending Time ---> 2022/03/28 14:41:28.662338,5388, , <-- (+0.000000) (11)[010B0457,0D0001E8,035BDA] [tx-queue:40] Receiving Time --> 2022/03/28 14:41:28.693591,5388, , --> (+0.031253) (9)[06090457,0D0001B0,1F] [tx-queue:40] Turnaround time : 0.031253 We want to know why windows takes more time as compared to Linux. We cannot put more debug logs in the application code. Below this layer, boost library play the role to transfer the data to the Serial port Regards, Rajesh D Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.

1 1

[release] 1.79.0 post-beta merges
by Marshall Clow 06 Apr '22

06 Apr '22

The master branch is is now open for post-beta merges, but only as described in the Post-Beta Merge Policy. See <https://github.com/boostorg/wiki/wiki/Releases%3A-Beta-Merge-Policy <https://github.com/boostorg/wiki/wiki/Releases%3A-Beta-Merge-Policy>> Reminder: The master branch closes for the release on Wednesday, April 6th. Full calendar here: https://www.boost.org/development/ <https://www.boost.org/development/> — Marshall P.S Doc changes and test changes do NOT require release manager approval to be merged.

7 12

So.... what are we going to do about modules?
by John Maddock 06 Apr '22

06 Apr '22

The title says it all really, but in more detail: 1) Is there any existing best practice we should follow yet? 2) Can we share code content effectively between headers and modules? And by modules I mean "proper" ones: we should be able to write "import boost.whatever;" rather than importing a header. 3) What directory structure should we all be using for module definition files? 4) Do we have Boost.Build support yet? 5) What file extensions should we be using? 6) I presume we would all use the boost.libraryname and boost.libraryname.sub_feature naming convention with boost.libraryname pulling in the whole library? 7) Does anyone have a handle on the current state of std library modularization? 8) Is there demand for this? And no doubt lots of other things I haven't thought of. Curiously yours, John.

11 27

Permission to merge bug fix to Outcome
by Niall Douglas 06 Apr '22

06 Apr '22

Issue being fixed is https://github.com/ned14/outcome/issues/259 where enabling of move assignment was not calculated correctly. (To be specific, if both T and E implement move assignment and default construction, but not move nor copy construction, we did not enable move assignment before and with this fix now we do) Code fixing it is at https://github.com/ned14/outcome/pull/260 Fix passes on develop branch at https://www.boost.org/development/tests/develop/developer/outcome.html Niall

2 4

Should boost have ofind(_if), that returns boost::optional<T&>?
by Ivan Matek 06 Apr '22

06 Apr '22

Hi, I have been thinking for this for a long time so I wanted to get the feedback from others. As you probably know better than me there is a bit of a drama <https://brevzin.github.io/c++/2021/12/13/optional-ref-ptr/>when it comes to std::optional<T&> and from what I see it will not be in C++23 for sure. I believe this gives an opportunity to boost to provide something nice for the users. Now the issues are the following: AFAIK boost only has old ranges and iterator based algorithms, ideally we would just have something like std:: ranges and add the ofind/ofind_if to those, but AFAIK those do not exist. So I think best thing would be to add it to boost::algorithm <https://github.com/boostorg/algorithm/tree/develop/include/boost/algorithm> . There are further questions like, should boost containers like map/unordered_map gain similar functionality, but I think deciding if we want the general algorithm is the first step. Another option I can think of is that those algorithms return something like a 0 or 1 element view(so you could access the optional value with range based for loop). This seems weird to me, so I would prefer boost::optional<T&>. There is s a short example on godbolt <https://godbolt.org/z/W9K3na9Gc>, but don't look at implementation too much, it was just something I hacked quickly, I am mostly interested in in feedback on if functionality would be nice addition to boost. regards, Ivan

5 9

regarding performance of boost::recursive_mutex::scoped_lock
by Daggumati, Rajesh 04 Apr '22

04 Apr '22

Hi Team, boost::recursive_mutex::scoped_lock behavior is same in linux and windows? I am getting some delay in my project which is in windows but same project in linux is not getting delayed. Regards, Rajesh D Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.

2 1

[release][multi_index] permission to merge to master
by Joaquin M López Muñoz 03 Apr '22

03 Apr '22

Hi, the following PR is absolutely trivial https://github.com/boostorg/multi_index/pull/57 but seems like it's important to Bitcoin guys in connection with an effort to prune internal Boost dependencies they're carrying out. Can I merge to master or should I wait till Boost 1.80? Thank you, Joaquín M López Muñoz

2 2

Re: [boost] Proposing a MySQL client library for inclusion in Boost
by Marcelo Zimbres Silva 02 Apr '22

02 Apr '22

Hi Ruben, I have had a look into your library and some questions arise > https://anarthal.github.io/mysql/mysql/ref/boost__mysql__resultset/async_re… > The handler signature for this operation is void(boost::mysql::error_code, std::vector<boost::mysql::row>). > etc. Having a std::vector in the signature of the completion handler is unusual in ASIO. In general large objects should be passed as parameters in the async operation e.g. socket::async_read gets a dynamic_buffer which is a lightweight view to storage. Additionally, there is not support for custom allocators. That wouldn't be a big problem to me if I could reuse the same memory for each request but the interface above prevents me from doing so. > https://anarthal.github.io/mysql/mysql/ref/boost__mysql__connection/async_q… > The handler signature for this operation is void(boost::mysql::error_code, boost::mysql::resultset<Stream>) Hier the completion handler is returning an io object i.e. boost::mysql::resultset, which is also unusual as far as I can see. Does that play nice with executors? I would prefer having the completion handler return config parameters with which I can instantiate a boost::mysql::resultset myself in my desired executor. > https://anarthal.github.io/mysql/mysql/ref/boost__mysql__connection.html I don't see a reason for this class, or at least I fail to see what state does the mysql protocol imposes on you that would justify this class. I would prefer free funcitions much more here, for example, in the same way as beast::http::async_read. > https://anarthal.github.io/mysql/mysql/ref/boost__mysql__value/get_std_opti… > https://anarthal.github.io/mysql/mysql/ref/boost__mysql__value/get_optional… Sounds also unusual to have two member functions for the different versions of optional. Regards, Marcelo

3 7

Boost.URL Proposal max_size
by Alan de Freitas 26 Mar '22

26 Mar '22

Hi! We're deciding on the max size for URLs in our Boost.URL proposal. The spec doesn't suggest a limit but the reasonable trade-off <https://stackoverflow.com/questions/417142/what-is-the-maximum-length-of-a-…> is: - 2^16 chars: More than all browsers, servers, and search engines support (~2000 chars). More than the HTTP minimum of 8000 octets. - 2^32 chars: "414 Too long request" in practice everywhere. Maybe supports experiments using URLs as a container for something else. Any suggestions? -- Alan Freitas https://github.com/alandefreitas

6 6

Determine interest in a possible library submission
by Keith Hiatt 21 Mar '22

21 Mar '22

Hi All, I was wondering about interest in some derived vector classes which support full vector functionality while adding the capabilities of mathematical operations on the datasets including matrix-based computations. Any thoughts would be appreciated. Thank you, Keith

3 2

Re: [boost] Boost Digest, Vol 6661, Issue 1
by Keith Hiatt 21 Mar '22

21 Mar '22

Hi Vinnie, It is almost complete. Is there a GIT repository where I can upload it? I have not been using a repository for my code and would like to do so. Thank you On Mon, Mar 21, 2022 at 8:00 AM <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > Today's Topics: > > 1. Re: [release] Boost 1.79.0 beta 1 released (Sal Pamukcu) > 2. Re: [release] Boost 1.79.0 beta 1 released (Jeff Trull) > 3. Determine interest in a possible library submission (Keith Hiatt) > 4. Re: Determine interest in a possible library submission > (Vinnie Falco) > > > > ---------- Forwarded message ---------- > From: Sal Pamukcu <salimp2009(a)gmail.com> > To: boost(a)lists.boost.org > Cc: > Bcc: > Date: Sun, 20 Mar 2022 19:40:51 +0300 > Subject: Re: [boost] [release] Boost 1.79.0 beta 1 released > On Fri, Mar 18, 2022 at 1:53 AM Andrey Semashev via Boost < > boost(a)lists.boost.org> wrote: > > > On 3/18/22 00:26, Sal Pamukcu via Boost wrote: > > > On Thu, Mar 17, 2022 at 11:24 PM Andrey Semashev via Boost < > > > boost(a)lists.boost.org> wrote: > > > > > >> On 3/17/22 22:31, Sal Pamukcu via Boost wrote: > > >>> - Compiled on Win 11 MSVC 2002 x64 toolchain with c++20 using > > >>> b2 cxxstd=20 --build-type=complete stage > > >>> > > >>> failed 5 target ; (mostly related to python) > > >>> The full built message are on gist ; > > >>> boost179b1_MSVC (github.com) > > >>> <https://gist.github.com/salimp2009/074cf168b4dd1231aa92fcc3845e2df7 > > > > >>> > > >>> I will do another build on windows with gcc-11.2 with MSys; > > >>> > > >>> ``` > > >>> ...failed updating 5 targets... > > >>> ...skipped 9 targets... > > >>> ...updated 8376 targets... > > >>> ``` > > >>> > > >>> Failures are like this ; > > >>> `...failed msvc.link.dll > > >>> > > >> > > > bin.v2\libs\python\build\msvc-14.3\debug\address-model-32\cxxstd-20-iso\python-3.10\threading-multi\boost_python310-vc143-mt-gd-x32-1_79.dll > > >>> > > >> > > > bin.v2\libs\python\build\msvc-14.3\debug\address-model-32\cxxstd-20-iso\python-3.10\threading-multi\boost_python310-vc143-mt-gd-x32-1_79.lib > > >>> > > >> > > > bin.v2\libs\python\build\msvc-14.3\debug\address-model-32\cxxstd-20-iso\python-3.10\threading-multi\boost_python310-vc143-mt-gd-x32-1_79.pdb...` > > >> > > >> Looks like the problem is that you're building 32-bit Boost.Python and > > >> linking with 64-bit Python libraries. I'm not sure if Boost.Python is > > >> supposed to find the correct libraries or this is just a user > > >> configuration error. > > > > > > Do you mean my configuration mistake; > > > i installed python 3.10 64 bit > > > and checked from MSVC VS 2022 64 bit command line using this ; > > > It looks like my Python is 64 bit; > > > > > > C:\Program Files\Microsoft Visual Studio\2022\Community> > > > C:\Program Files\Microsoft Visual Studio\2022\Community>python > > > Python 3.10.0 (tags/v3.10.0:b494f59, Oct 4 2021, 19:00:18) [MSC v.1929 > > 64 > > > bit (AMD64)] on win32 > > > Type "help", "copyright", "credits" or "license" for more information. > > >>>> import struct > > >>>> version = struct.calcsize("P")*8 > > >>>> print(version) > > > 64 > > >>>> > > > > > > is there a way to configure when building with b2 > > > I used this ; b2 cxxstd=20 --build-type=complete stage > > > > By default both 32 and 64-bit Boost binaries are built. To build only > > 64-bit binaries you can add address-model=64 to the b2 command line. If > > you want to build 32-bit libraries, use address-model=32 and also make > > sure 32-bit Python libraries are found by the build process. > > > > _______________________________________________ > > Unsubscribe & other changes: > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > I did another build on Windows 11 ; this time using gcc-11.2 (via MSys2 > MinGW), c++20 > I did 2 runs one on command line and one on x64 Native Tool MSCV 2022 > Also used address-model=64 to avoid Python 32-bit > No errors but compiled way less files this time ; typically it was around > ~8000+ > this time "...updated 3693 targets.." > command line i used ; > b2 cxxstd=20 address-model=64 toolset=gcc --build-type=complete stage > > as usual got warning for auto_ptr and this one ; > > C:/msys64/mingw64/include/c++/11.2.0/ext/new_allocator.h:145:26: warning: > 'void operator delete(void*, std::size_t)' called on unallocated object > 'boost::wave::util::SimpleStringStorage<char, std::allocator<char> > >::emptyString_' [-Wfree-nonheap-object] > 145 | ::operator delete(__p > | ~~~~~~~~~~~~~~~~~^~~~ > 146 | #if __cpp_sized_deallocation > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 147 | , __t * sizeof(_Tp) > | ~~~~~~~~~~~~~~~~~~~ > 148 | #endif > | ~~~~~~ > 149 | ); > > If needed I can put the whole build outputs on gist. > > Only one question is it normal to use address-model=64 or should this be > detected thru b2 or CMake and if it causes any other needed > libraries skipped because there was quite a bit of difference in the > updated amount > > Salim Pamukcu > > > > > ---------- Forwarded message ---------- > From: Jeff Trull <linmodemstudent(a)gmail.com> > To: Boost Developers List <boost(a)lists.boost.org> > Cc: > Bcc: > Date: Sun, 20 Mar 2022 10:21:18 -0700 > Subject: Re: [boost] [release] Boost 1.79.0 beta 1 released > On Sun, Mar 20, 2022 at 9:41 AM Sal Pamukcu via Boost < > boost(a)lists.boost.org> > wrote: > > > On Fri, Mar 18, 2022 at 1:53 AM Andrey Semashev via Boost < > > boost(a)lists.boost.org> wrote: > > > > > On 3/18/22 00:26, Sal Pamukcu via Boost wrote: > > > > On Thu, Mar 17, 2022 at 11:24 PM Andrey Semashev via Boost < > > > > boost(a)lists.boost.org> wrote: > > > > > > > >> On 3/17/22 22:31, Sal Pamukcu via Boost wrote: > > > >>> - Compiled on Win 11 MSVC 2002 x64 toolchain with c++20 using > > > >>> b2 cxxstd=20 --build-type=complete stage > > > >>> > > > >>> failed 5 target ; (mostly related to python) > > > >>> The full built message are on gist ; > > > >>> boost179b1_MSVC (github.com) > > > >>> < > https://gist.github.com/salimp2009/074cf168b4dd1231aa92fcc3845e2df7 > > > > > > >>> > > > >>> I will do another build on windows with gcc-11.2 with MSys; > > > >>> > > > >>> ``` > > > >>> ...failed updating 5 targets... > > > >>> ...skipped 9 targets... > > > >>> ...updated 8376 targets... > > > >>> ``` > > > >>> > > > >>> Failures are like this ; > > > >>> `...failed msvc.link.dll > > > >>> > > > >> > > > > > > bin.v2\libs\python\build\msvc-14.3\debug\address-model-32\cxxstd-20-iso\python-3.10\threading-multi\boost_python310-vc143-mt-gd-x32-1_79.dll > > > >>> > > > >> > > > > > > bin.v2\libs\python\build\msvc-14.3\debug\address-model-32\cxxstd-20-iso\python-3.10\threading-multi\boost_python310-vc143-mt-gd-x32-1_79.lib > > > >>> > > > >> > > > > > > bin.v2\libs\python\build\msvc-14.3\debug\address-model-32\cxxstd-20-iso\python-3.10\threading-multi\boost_python310-vc143-mt-gd-x32-1_79.pdb...` > > > >> > > > >> Looks like the problem is that you're building 32-bit Boost.Python > and > > > >> linking with 64-bit Python libraries. I'm not sure if Boost.Python > is > > > >> supposed to find the correct libraries or this is just a user > > > >> configuration error. > > > > > > > > Do you mean my configuration mistake; > > > > i installed python 3.10 64 bit > > > > and checked from MSVC VS 2022 64 bit command line using this ; > > > > It looks like my Python is 64 bit; > > > > > > > > C:\Program Files\Microsoft Visual Studio\2022\Community> > > > > C:\Program Files\Microsoft Visual Studio\2022\Community>python > > > > Python 3.10.0 (tags/v3.10.0:b494f59, Oct 4 2021, 19:00:18) [MSC > v.1929 > > > 64 > > > > bit (AMD64)] on win32 > > > > Type "help", "copyright", "credits" or "license" for more > information. > > > >>>> import struct > > > >>>> version = struct.calcsize("P")*8 > > > >>>> print(version) > > > > 64 > > > >>>> > > > > > > > > is there a way to configure when building with b2 > > > > I used this ; b2 cxxstd=20 --build-type=complete stage > > > > > > By default both 32 and 64-bit Boost binaries are built. To build only > > > 64-bit binaries you can add address-model=64 to the b2 command line. If > > > you want to build 32-bit libraries, use address-model=32 and also make > > > sure 32-bit Python libraries are found by the build process. > > > > > > _______________________________________________ > > > Unsubscribe & other changes: > > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > > I did another build on Windows 11 ; this time using gcc-11.2 (via MSys2 > > MinGW), c++20 > > I did 2 runs one on command line and one on x64 Native Tool MSCV 2022 > > Also used address-model=64 to avoid Python 32-bit > > No errors but compiled way less files this time ; typically it was around > > ~8000+ > > this time "...updated 3693 targets.." > > command line i used ; > > b2 cxxstd=20 address-model=64 toolset=gcc --build-type=complete stage > > > > as usual got warning for auto_ptr and this one ; > > > > C:/msys64/mingw64/include/c++/11.2.0/ext/new_allocator.h:145:26: warning: > > 'void operator delete(void*, std::size_t)' called on unallocated object > > 'boost::wave::util::SimpleStringStorage<char, std::allocator<char> > > >::emptyString_' [-Wfree-nonheap-object] > > 145 | ::operator delete(__p > > | ~~~~~~~~~~~~~~~~~^~~~ > > 146 | #if __cpp_sized_deallocation > > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > 147 | , __t * sizeof(_Tp) > > | ~~~~~~~~~~~~~~~~~~~ > > 148 | #endif > > | ~~~~~~ > > 149 | ); > > > > If needed I can put the whole build outputs on gist. > > > This looks like the same issue as > https://github.com/boostorg/wave/issues/159. > I think it's a new analysis in gcc 11 that we haven't seen before (and > therefore not > a regression). > > > > > Only one question is it normal to use address-model=64 or should this be > > detected thru b2 or CMake and if it causes any other needed > > libraries skipped because there was quite a bit of difference in the > > updated amount > > > > Salim Pamukcu > > > > _______________________________________________ > > Unsubscribe & other changes: > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > > ---------- Forwarded message ---------- > From: Keith Hiatt <keith.x.hiatt(a)gmail.com> > To: boost(a)lists.boost.org > Cc: > Bcc: > Date: Sun, 20 Mar 2022 21:55:50 -0400 > Subject: [boost] Determine interest in a possible library submission > Hi All, > > I was wondering about interest in some derived vector classes which support > full vector functionality while adding the capabilities of mathematical > operations on the datasets including matrix-based computations. > > Any thoughts would be appreciated. > > Thank you, > Keith > > > > > ---------- Forwarded message ---------- > From: Vinnie Falco <vinnie.falco(a)gmail.com> > To: "boost(a)lists.boost.org List" <boost(a)lists.boost.org> > Cc: > Bcc: > Date: Sun, 20 Mar 2022 22:48:54 -0700 > Subject: Re: [boost] Determine interest in a possible library submission > On Sun, Mar 20, 2022 at 10:03 PM Keith Hiatt via Boost > <boost(a)lists.boost.org> wrote: > > I was wondering about interest in some derived vector classes which > support > > full vector functionality while adding the capabilities of mathematical > > operations on the datasets including matrix-based computations. > > If this is already written, could you please share a link? > > Thanks > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost >

1 0

Boost 1.78.0 build issue
by Daggumati, Rajesh 21 Mar '22

21 Mar '22

Hi Team, I have built 1.76.0 sucessfully in my visual studio 2019 but when I try to build boost 1.78.0, I am facing some linker issue like below. Please help me to fix it. Severity Code Description Project File Line Suppression State Error LNK1104 cannot open file 'libboost_filesystem-vc142-mt-gd-x64-1_78.lib' checksum-writer-xml C:\Projects\Abba\src-cpp\src\apps\checksum-writer-xml\LINK 1 Error LNK1104 cannot open file 'libboost_filesystem-vc142-mt-gd-x64-1_78.lib' IPLUtilityTest C:\Projects\Abba\src-cpp\src\modules\IPLUtilityTest\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' FoundationQtTest C:\Projects\Abba\src-cpp\src\modules\FoundationQtTest\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' FoundationTest C:\Projects\Abba\src-cpp\src\modules\FoundationTest\LINK 1 Error LNK1104 cannot open file 'libboost_program_options-vc142-mt-gd-x64-1_78.lib' console-test-harness C:\Projects\Abba\src-cpp\src\apps\console-test-harness\LINK 1 Error LNK1104 cannot open file 'libboost_filesystem-vc142-mt-gd-x64-1_78.lib' InstrumentTest C:\Projects\Abba\src-cpp\src\modules\InstrumentTest\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' InstrumentQtTest C:\Projects\Abba\src-cpp\src\modules\InstrumentQtTest\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' widget-test-harness C:\Projects\Abba\src-cpp\src\apps\widget-test-harness\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' cytiva-aktaflux C:\Projects\Abba\src-cpp\src\apps\cytiva-aktaflux\LINK 1 Regards, Rajesh D Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.

1 0

Boost 1.78.0 build issue
by Daggumati, Rajesh 21 Mar '22

21 Mar '22

Hi Team, I have built 1.76.0 sucessfully in my visual studio 2019 but when I try to build boost 1.78.0, I am facing some linker issue like below. Please help me to fix it. Severity Code Description Project File Line Suppression State Error LNK1104 cannot open file 'libboost_filesystem-vc142-mt-gd-x64-1_78.lib' checksum-writer-xml C:\Projects\Abba\src-cpp\src\apps\checksum-writer-xml\LINK 1 Error LNK1104 cannot open file 'libboost_filesystem-vc142-mt-gd-x64-1_78.lib' IPLUtilityTest C:\Projects\Abba\src-cpp\src\modules\IPLUtilityTest\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' FoundationQtTest C:\Projects\Abba\src-cpp\src\modules\FoundationQtTest\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' FoundationTest C:\Projects\Abba\src-cpp\src\modules\FoundationTest\LINK 1 Error LNK1104 cannot open file 'libboost_program_options-vc142-mt-gd-x64-1_78.lib' console-test-harness C:\Projects\Abba\src-cpp\src\apps\console-test-harness\LINK 1 Error LNK1104 cannot open file 'libboost_filesystem-vc142-mt-gd-x64-1_78.lib' InstrumentTest C:\Projects\Abba\src-cpp\src\modules\InstrumentTest\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' InstrumentQtTest C:\Projects\Abba\src-cpp\src\modules\InstrumentQtTest\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' widget-test-harness C:\Projects\Abba\src-cpp\src\apps\widget-test-harness\LINK 1 Error LNK1104 cannot open file 'libboost_thread-vc142-mt-gd-x64-1_78.lib' cytiva-aktaflux C:\Projects\Abba\src-cpp\src\apps\cytiva-aktaflux\LINK 1 Regards, Rajesh D Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.

1 0

[release] Boost 1.79.0 beta 1 released
by Marshall Clow 20 Mar '22

20 Mar '22

Boost release 1.79.0 beta 1 is now available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.79.0.beta1/source/> The SHA256 checksums are as follows: 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf boost_1_79_0_b1.tar.bz2 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 boost_1_79_0_b1.tar.gz 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 boost_1_79_0_b1.7z 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b boost_1_79_0_b1.zip For details of what's in the release, see <https://www.boost.org/users/history/version_1_79_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

4 6

numeric_cast should work with enum's
by Frederick Virchanza Gotham 16 Mar '22

16 Mar '22

(Sometimes Gmail takes out white space so I'm hoping this post is indented properly.) I think that "numeric_cast" should be able to cast to and from enum types, so that it can be used as follows: #include <cstdint> #include <iostream> using std::cout; using std::endl; enum class Toad : std::uint8_t { Purple, Orange = 0x7f }; enum class Frog { Blue, Yellow, Pink = 0xFFFFu }; int main(void) { try { numeric_cast<Toad>( Frog::Pink ); } catch(std::exception const &e) { cout << e.what() << endl; } std::uint32_t my_32_bit_var = 0xffffffffU; try { numeric_cast<std::uint16_t>(my_32_bit_var); } catch(std::exception const &e) { cout << e.what() << endl; } try { numeric_cast<std::uint8_t>( Frog::Pink ); } catch(std::exception const &e) { cout << e.what() << endl; } try { numeric_cast<Toad>(0x1FFu); } catch(std::exception const &e) { cout << e.what() << endl; } } In order to achieve this behaviour, I've created my own "numeric_cast" in the global namespace as follows: #include <type_traits> // is_enum, underlying_type #include <boost/numeric/conversion/cast.hpp> // numeric_cast template<bool T_is_an_enum, typename T> struct numeric_cast_helper { typedef T type; }; template<typename T> struct numeric_cast_helper<true, T> { typedef typename std::underlying_type<T>::type type; }; template<typename A, typename B> A numeric_cast(B const b) // This function takes its argument by value, and also returns by value -- which is fine for arithmetic types { return static_cast<A>( boost::numeric_cast<typename numeric_cast_helper<std::is_enum<A>::value, A>::type> ( static_cast<typename numeric_cast_helper<std::is_enum<B>::value, B>::type>(b) ) ); }

1 0

Fwd: Boost Digest, Vol 6656, Issue 1
by Sal Pamukcu 11 Mar '22

11 Mar '22

---------- Forwarded message --------- From: <boost-request(a)lists.boost.org> Date: Fri, Mar 11, 2022 at 3:00 PM Subject: Boost Digest, Vol 6656, Issue 1 To: <boost(a)lists.boost.org> Send Boost mailing list submissions to boost(a)lists.boost.org To subscribe or unsubscribe via the World Wide Web, visit https://lists.boost.org/mailman/listinfo.cgi/boost or, via email, send a message with subject or body 'help' to boost-request(a)lists.boost.org You can reach the person managing the list at boost-owner(a)lists.boost.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Boost digest..." The boost archives may be found at: http://lists.boost.org/Archives/boost/ Today's Topics: 1. Re: [Graph] Attempt to resolve open issue (Anne van de Graaf) 2. Master branch now closed for 1.79.0 beta release (Marshall Clow) 3. [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available (Marshall Clow) 4. Re: [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available (Marshall Clow) 5. Re: [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available (Andrey Semashev) 6. Re: [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available (Marshall Clow) 7. Re: [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available (Andrey Semashev) 8. Re: [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available (Tom Kent) 9. Re: [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available (Matt Borland) 10. Re: [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available (Andrey Semashev) ---------- Forwarded message ---------- From: Anne van de Graaf <A.vandeGraaf(a)dianafea.com> To: Jeremy Murphy <jeremy.william.murphy(a)gmail.com> Cc: "boost(a)lists.boost.org" <boost(a)lists.boost.org>, John Maddock < jz.maddock(a)googlemail.com> Bcc: Date: Thu, 10 Mar 2022 13:17:37 +0000 Subject: Re: [boost] [Graph] Attempt to resolve open issue > This is fixed on the develop branch, btw, have you verified that it works as expected now? Apologies for my late reply. Yes, I have verified that the fix on the develop branch works as expected. Thank you very much for the work that you have done. Best regards, Anne On Fri, 10 Dec 2021 at 18:56, Anne van de Graaf <A.vandeGraaf(a)dianafea.com <mailto:A.vandeGraaf@dianafea.com>> wrote: > Hi Anne, > which issue or pull request # is it? Hi Jeremy, It is issue # 268: https://github.com/boostorg/graph/issues/268 Best regards, Anne > Jeremy On Sun, 5 Dec 2021 at 02:20, Anne van de Graaf via Boost < boost(a)lists.boost.org<mailto:boost@lists.boost.org>> wrote: > Hello all, > > I am trying to get an open issue in Boost.Graph resolved. Since I haven't received any response at the corresponding GitHub page nor from the Boost Users mailing list (where I posted the below message last Monday), I am reaching out to you. My aim is to get in touch with the maintainer(s) of Boost.Graph in order to discuss what is the preferred/most efficient way to fix the issue. Since this is my first post to this mailing list, please accept my apologies if you feel this is not the right way to get in touch with the maintainers. In that case, I would appreciate it very much if you could kindly explain what I should have done instead. Please find below a copy of my message that I sent last Monday to the Boost Users mailing list. Thank you very much for your attention and any replies. > Unfortunately, Graph has no current maintainer. I have done some > maintenance on that library in the past, and I know Jeremy Murphy will > be trying to do some this next week, so hopefully one of us can get that > one fixed! Thanks a lot for your reply, John. I didn't know that Boost.Graph doesn't have a current maintainer. It would be great if you or Jeremy could do some maintenance on it. Feel free to contact me if I can help you in any way to get things done. We could then discuss in what way I can contribute. Thanks. Kind regards, Anne > Best, John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost ---------- Forwarded message ---------- From: Marshall Clow <mclow.lists(a)gmail.com> To: Boost Developers List <boost(a)lists.boost.org> Cc: Bcc: Date: Thu, 10 Mar 2022 06:31:06 -0800 Subject: [boost] Master branch now closed for 1.79.0 beta release Please do not make any commits to the master branch. — Marshall ---------- Forwarded message ---------- From: Marshall Clow <mclow.lists(a)gmail.com> To: Boost Developers List <boost(a)lists.boost.org> Cc: Bcc: Date: Thu, 10 Mar 2022 07:27:19 -0800 Subject: [boost] [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available are now available at: <https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source < https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source>> The SHA256 checksums are as follows: 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf boost_1_79_0_b1_rc1.tar.bz2 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 boost_1_79_0_b1_rc1.tar.gz 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b boost_1_79_0_b1_rc1.zip 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 boost_1_79_0_b1_rc1.7z As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release Managers It fails on Window 11 using GCC-11.2 command line ; b2 cxxstd=20 toolset=gcc --build-type=complete stage here is the error message ; FailBoost1.79.0 Beta 1 Release Candidate 1 (github.com) <https://gist.github.com/salimp2009/854b3c74295b2487c4585be35f8bfbd0> Salim (a new bee in devel :) ---------- Forwarded message ---------- From: Marshall Clow <mclow.lists(a)gmail.com> To: Boost Developers List <boost(a)lists.boost.org> Cc: Bcc: Date: Thu, 10 Mar 2022 08:03:12 -0800 Subject: Re: [boost] [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available On Mar 10, 2022, at 7:27 AM, Marshall Clow <mclow.lists(a)gmail.com> wrote: > > are now available at: > <https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source < https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source>> > > The SHA256 checksums are as follows: > > 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf boost_1_79_0_b1_rc1.tar.bz2 > 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 boost_1_79_0_b1_rc1.tar.gz > 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b boost_1_79_0_b1_rc1.zip > 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 boost_1_79_0_b1_rc1.7z > > As always, the release managers would appreciate it if you download the > candidate of your choice and give building it a try. Please report both > success and failure, and anything else that is noteworthy. I have successfully built the libraries: * On Mac OS 10.15, using Apple clang version 11.0.3, and and c++03/11/14/17/2a — Marshall ---------- Forwarded message ---------- From: Andrey Semashev <andrey.semashev(a)gmail.com> To: boost(a)lists.boost.org Cc: Bcc: Date: Thu, 10 Mar 2022 20:17:42 +0300 Subject: Re: [boost] [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available On 3/10/22 18:27, Marshall Clow via Boost wrote: > are now available at: > <https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source < https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source>> > > The SHA256 checksums are as follows: > > 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf boost_1_79_0_b1_rc1.tar.bz2 > 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 boost_1_79_0_b1_rc1.tar.gz > 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b boost_1_79_0_b1_rc1.zip > 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 boost_1_79_0_b1_rc1.7z > > As always, the release managers would appreciate it if you download the > candidate of your choice and give building it a try. Please report both > success and failure, and anything else that is noteworthy. I'm trying to download the source package now, and the download speed is terrible, ~30-60 KB/s. Is this expected? ---------- Forwarded message ---------- From: Marshall Clow <mclow.lists(a)gmail.com> To: boost(a)lists.boost.org Cc: Bcc: Date: Thu, 10 Mar 2022 09:53:08 -0800 Subject: Re: [boost] [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available On Mar 10, 2022, at 9:17 AM, Andrey Semashev via Boost < boost(a)lists.boost.org> wrote: > > On 3/10/22 18:27, Marshall Clow via Boost wrote: >> are now available at: >> <https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source < https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source>> >> >> The SHA256 checksums are as follows: >> >> 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf boost_1_79_0_b1_rc1.tar.bz2 >> 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 boost_1_79_0_b1_rc1.tar.gz >> 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b boost_1_79_0_b1_rc1.zip >> 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 boost_1_79_0_b1_rc1.7z >> >> As always, the release managers would appreciate it if you download the >> candidate of your choice and give building it a try. Please report both >> success and failure, and anything else that is noteworthy. > > I'm trying to download the source package now, and the download speed is > terrible, ~30-60 KB/s. Is this expected? That’s not what I’m seeing. I’m getting > 1 MB/sec — Marshall ---------- Forwarded message ---------- From: Andrey Semashev <andrey.semashev(a)gmail.com> To: boost(a)lists.boost.org Cc: Bcc: Date: Thu, 10 Mar 2022 21:25:53 +0300 Subject: Re: [boost] [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available On 3/10/22 20:53, Marshall Clow via Boost wrote: > On Mar 10, 2022, at 9:17 AM, Andrey Semashev via Boost < boost(a)lists.boost.org> wrote: >> >> On 3/10/22 18:27, Marshall Clow via Boost wrote: >>> are now available at: >>> <https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source < https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source>> >>> >>> The SHA256 checksums are as follows: >>> >>> 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf boost_1_79_0_b1_rc1.tar.bz2 >>> 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 boost_1_79_0_b1_rc1.tar.gz >>> 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b boost_1_79_0_b1_rc1.zip >>> 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 boost_1_79_0_b1_rc1.7z >>> >>> As always, the release managers would appreciate it if you download the >>> candidate of your choice and give building it a try. Please report both >>> success and failure, and anything else that is noteworthy. >> >> I'm trying to download the source package now, and the download speed is >> terrible, ~30-60 KB/s. Is this expected? > > That’s not what I’m seeing. > I’m getting > 1 MB/sec Possibly, some regional restrictions on JFrog side? I'm not seeing bandwidth issues on other sites, including GitHub, which I assume is US based. BTW, building with gcc 11.2 in C++17 mode on Kubuntu 21.10 succeeds. There are quite a few warnings about auto_ptr being deprecated, and also some suspicious warnings about freeing non-heap-allocated objects in Boost.Wave: https://github.com/boostorg/wave/issues/159 ---------- Forwarded message ---------- From: Tom Kent <lists(a)teeks99.com> To: Boost Developers List <boost(a)lists.boost.org> Cc: Bcc: Date: Thu, 10 Mar 2022 15:33:30 -0600 Subject: Re: [boost] [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available On Thu, Mar 10, 2022 at 9:27 AM Marshall Clow via Boost < boost(a)lists.boost.org> wrote: > are now available at: > <https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source < > https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source>> > > The SHA256 checksums are as follows: > > 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf > boost_1_79_0_b1_rc1.tar.bz2 > 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 > boost_1_79_0_b1_rc1.tar.gz > 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b > boost_1_79_0_b1_rc1.zip > 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 > boost_1_79_0_b1_rc1.7z > > As always, the release managers would appreciate it if you download the > candidate of your choice and give building it a try. Please report both > success and failure, and anything else that is noteworthy. > > -- The Release Managers > Looks good on Windows/Visual Studio. toolset arch compile Link Execute msvc-10.0 32 X X X msvc-10.0 64 X X X msvc-11.0 32 X X X msvc-11.0 64 X X X msvc-12.0 32 X X X msvc-12.0 64 X X X msvc-14.0 32 X X X msvc-14.0 64 X X X msvc-14.1 32 X X X msvc-14.1 64 X X X msvc-14.2 32 X X X msvc-14.2 64 X X X msvc-14.3 32 X X X msvc-14.3 64 X X X Compile means that the b2 command completed without errors Link means that visual studio was able to link a sample executable to a library (libboost_thread-vcXXX-mt[-gd]-1_XX.lib) generated Execute means that the linked program executed without errors. Full build logs can be found here: https://gist.github.com/teeks99/acf919a716deeb001acaa2b4f12cb757 Tom ---------- Forwarded message ---------- From: Matt Borland <matt(a)mattborland.com> To: boost(a)lists.boost.org Cc: Bcc: Date: Fri, 11 Mar 2022 10:57:15 +0000 Subject: Re: [boost] [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available > As always, the release managers would appreciate it if you download the > > candidate of your choice and give building it a try. Please report both > > success and failure, and anything else that is noteworthy. > > -- The Release Managers > > _______________________________________________ Boost.Filesystem fails to build using Apple Clang 13 with C++11/14/17/20 on M1 Pro Architecture. An issue has been opened here ( https://github.com/boostorg/filesystem/issues/231) Matt ---------- Forwarded message ---------- From: Andrey Semashev <andrey.semashev(a)gmail.com> To: boost(a)lists.boost.org Cc: Bcc: Date: Fri, 11 Mar 2022 14:09:22 +0300 Subject: Re: [boost] [release] Boost 1.79.0 Beta 1 Release Candidate 1 is available On 3/11/22 13:57, Matt Borland via Boost wrote: >> As always, the release managers would appreciate it if you download the >> >> candidate of your choice and give building it a try. Please report both >> >> success and failure, and anything else that is noteworthy. >> >> -- The Release Managers >> >> _______________________________________________ > > Boost.Filesystem fails to build using Apple Clang 13 with C++11/14/17/20 on M1 Pro Architecture. An issue has been opened here ( https://github.com/boostorg/filesystem/issues/231) As replied in the issue, your build is picking up headers from a different Boost version in /usr/local/include. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost -- Salim Pamukcu

1 0

[release] Boost 1.79.0 Beta 1 Release Candidate 1 is available
by Marshall Clow 11 Mar '22

11 Mar '22

are now available at: <https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source <https://boostorg.jfrog.io/ui/native/main/beta/1.79.0.beta1/source>> The SHA256 checksums are as follows: 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf boost_1_79_0_b1_rc1.tar.bz2 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 boost_1_79_0_b1_rc1.tar.gz 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b boost_1_79_0_b1_rc1.zip 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 boost_1_79_0_b1_rc1.7z As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release Managers

4 8

Master branch now closed for 1.79.0 beta release
by Marshall Clow 10 Mar '22

10 Mar '22

Please do not make any commits to the master branch. — Marshall

1 0

[Graph] Attempt to resolve open issue
by Anne van de Graaf 10 Mar '22

10 Mar '22

Hello all, I am trying to get an open issue in Boost.Graph resolved. Since I haven't received any response at the corresponding GitHub page nor from the Boost Users mailing list (where I posted the below message last Monday), I am reaching out to you. My aim is to get in touch with the maintainer(s) of Boost.Graph in order to discuss what is the preferred/most efficient way to fix the issue. Since this is my first post to this mailing list, please accept my apologies if you feel this is not the right way to get in touch with the maintainers. In that case, I would appreciate it very much if you could kindly explain what I should have done instead. Please find below a copy of my message that I sent last Monday to the Boost Users mailing list. Thank you very much for your attention and any replies. Original message: When I remove a vertex from a graph, I occasionally experience a crash (on a system running Red Hat Enterprise Linux 8.5). I have been able to replicate the behavior with the following test program: #include <vector> #include <boost/graph/adjacency_list.hpp> int main() { using MyGraph = boost::adjacency_list<boost::setS, boost::vecS, boost::undirectedS>; using MyVertexDescriptor = boost::graph_traits<MyGraph>::vertex_descriptor; using MyVertexDescriptorVec = std::vector<MyVertexDescriptor>; MyGraph g; MyVertexDescriptorVec vertices{ boost::add_vertex( g ), boost::add_vertex( g ), boost::add_vertex( g ) }; boost::add_edge( vertices[0], vertices[1], g ); boost::add_edge( vertices[1], vertices[2], g ); boost::clear_vertex( vertices[0], g ); boost::remove_vertex( vertices[0], g ); return 0; } Also on a Windows platform, I observe similar behavior. When I build the above code with Microsoft Visual Studio 2019 (MSVC 14.27.29110) and run it with a debugger, a debug assertion is triggered ("cannot increment value-initialized map/set iterator"). In both cases (on Linux and Windows platforms), the debugger reveals that the problem is at line 2071 of boost/graph/detail/adjacency_list.hpp. For clarity, I have copied the involved template function below: template < class EdgeList, class vertex_descriptor > inline void reindex_edge_list( EdgeList& el, vertex_descriptor u, boost::disallow_parallel_edge_tag) { for (typename EdgeList::iterator ei = el.begin(); ei != el.end(); ++ei) // line 2071: increment operator fails { if (ei->get_target() > u) { typename EdgeList::value_type ce = *ei; el.erase(ce); --ce.get_target(); el.insert(ce); } } } While I was searching for a proper place to post my question, I found the following issue at GitHub (which was opened on July 1 of this year): https://github.com/boostorg/graph/issues/268. This appears to be the exact same issue. So last week, I added a comment saying that I am facing the exact same problem. Unfortunately, so far no one has responded yet. To me, it seems that the problem is well-understood. Also, some have proposed a bug fix to resolve the issue (including a pull request). Nevertheless, no progress has been made over the past months. So I was just wondering what is the best way to proceed if we want to fix the issue in Boost itself? Is there anything that I can do (apart from starting this thread) to help in resolving the issue? Any feedback is greatly appreciated. Kind regards, Anne van de Graaf

3 6

Windows Build Issue for Boost Wave
by Tom Kent 09 Mar '22

09 Mar '22

In preparation for the lockdown today, I did a dry run of the windows build based on the latest snapshot. During this build I encountered errors with wave on the msvc-12.0 compiler (both 32 & 64 bit). Roughly the following is repeated several times during the build: compile-c-c++ D:\RB\bin.v2\boost\bin.v2\libs\wave\build\msvc-12.0\debug\address-model-32\threading-multi\token_ids.obj token_ids.cpp D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(335) : error C2146: syntax error : missing ';' before identifier 'token_id' D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(335) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(341) : error C2146: syntax error : missing ';' before identifier 'token_id' D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(341) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(341) : error C2086: 'int boost::wave::constexpr' : redefinition D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(335) : see declaration of 'boost::wave::constexpr' D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(347) : error C2144: syntax error : 'bool' should be preceded by ';' D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(347) : error C4430: missing type specifier - int assumed. Note: C++ does not support default-int D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(347) : error C2086: 'int boost::wave::constexpr' : redefinition D:\RB\boost_1_79_0\boost/wave/token_ids.hpp(335) : see declaration of 'boost::wave::constexpr' call "D:\RB\bin.v2\boost\bin.v2\standalone\msvc\msvc-12.0\address-model-32\architecture-x86\msvc-setup.bat" x86 >nul cl /Zm800 -nologo "libs\wave\src\token_ids.cpp" -c -Fo"D:\RB\bin.v2\boost\bin.v2\libs\wave\build\msvc-12.0\debug\address-model-32\threading-multi\token_ids.obj" -TP /wd4675 /EHs /GR /Z7 /Od /Ob0 /W3 /MDd /Zc:forScope /Zc:wchar_t /Zc:inline -DBOOST_ALL_DYN_LINK=1 -DBOOST_ALL_NO_LIB=1 -D_CRT_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_DEPRECATE "-I." ...failed compile-c-c++ D:\RB\bin.v2\boost\bin.v2\libs\wave\build\msvc-12.0\debug\address-model-32\threading-multi\token_ids.obj... Hope this helps, if not fixed it will be blocking the beta rc when it gets rolled. Tom

1 0

Boost 1.79.0 closed for breaking changes and new libraries today
by Glen Fernandes 02 Mar '22

02 Mar '22

We are closed for new libraries and breaking changes today. We will close for all major changes this Friday (2022-03-04). And will close for the beta the following Wednesday (2022-03-09). The Release Managers

1 0

std::numeric_limits<__float128>::signaling_NaN + __float128-Type
by Gero Peterhoff 26 Feb '22

26 Feb '22

Hello, please see https://godbolt.org/z/Ksshxvhaj 1) std::numeric_limits<__float128>::signaling_NaN always returns 0 but gcc-__builtin_nansq doesn't. I think __builtin_nansq is correct as it is also distinct from std::numeric_limits<__float128>::quiet_NaN (__builtin_nanq). 2) The types __float128, __extension__ __float128 (gcc) and _Quad (intel) are identical, but there are different definitions in boost/config/detail/suffix.hpp and boost/math/cstdfloat/cstdfloat_types.hpp. I think it would make sense to have just one definition or is there a reason why it was done that way? If yes, which one is it? You could always use __float128 directly and/or adjust boost/config/detail/suffix.hpp so that it also works with clang/intel. Which way would be better? I would like to help consolidate this but without having to deal with different typedef's or long #define's. thx Gero

3 13

Boost.URL Proposal
by Alan de Freitas 21 Feb '22

21 Feb '22

Hi! My name is Alan Freitas. Vinnie Falco and I are looking for a review manager for the library that we hope will become Boost.URL. I've taken over the project and in addition to introducing myself I would like to update you guys as to where we are on this in terms of progress: - Path segments can be represented as views of the underlying path - Query parameters can be represented as views of the underlying query - Percent-decoding methods return lazy constant strings with small buffer optimization and shared ownership - The library implements the specification as in RFC3986 <https://datatracker.ietf.org/doc/html/rfc3986> + its errata <https://www.rfc-editor.org/errata/rfc3986> - Non-ASCII characters are not considered valid URLs - Other specifications such as RFC3492 <https://datatracker.ietf.org/doc/html/rfc3492>, WhatWG <https://url.spec.whatwg.org/>, or any other form of relaxed parsing are out of the scope of the library Both Vinnie and I are available to answer questions about the library on the list, on the GitHub repository page <https://github.com/CPPAlliance/url>, via email <alandefreitas(a)gmail.com>, or on Slack (in #boost-url). -- Alan Freitas https://github.com/alandefreitas

5 7

Understanding the code base.
by Rahul Sharma 21 Feb '22

21 Feb '22

So far I have been reading multiple documentations and reading the projects from past year GSoC and exploring some modules given on the GitHub and I came to understand now that in order to contribute to this organization the knowledge of only C++ and data structures is not enough. I have some questions which are halting my progress so far, it would be very generous of you if someone could address these issues I am facing…… 1. I am unable to understand the code base in the repositories on GitHub. 2. In order to contribute or to understand things in a better way do I need to learn how Boost libraries work. 3. What are some packages I need to install. It would be very kind of you if you could provide some useful resources for the same and also for the things you think could be of use to understand things clearly and for making some PRs. When I read the code base of some repositories and some documentations I got excited as I think there are many things and skills I need to learn, the skills, it takes to be a decent developer. Sent from [1]Mail for Windows References 1. https://go.microsoft.com/fwlink/?LinkId=550986

2 1

[PATCH] futex: fix build on 32-bit architectures using 64-bit time_t
by Khem Raj 21 Feb '22

21 Feb '22

Fix the following build failure on 32-bit architectures using 64-bit time_t (e.g. riscv32): | ./boost/fiber/detail/futex.hpp:31:23: error: use of undeclared identifier 'SYS_futex' | return ::syscall( SYS_futex, addr, op, x, nullptr, nullptr, 0); | ^ | 1 error generated. Signed-off-by: Khem Raj <raj.khem(a)gmail.com> --- boost/fiber/detail/futex.hpp | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/boost/fiber/detail/futex.hpp b/boost/fiber/detail/futex.hpp index e64bd5990..d0353e9e5 100644 --- a/boost/fiber/detail/futex.hpp +++ b/boost/fiber/detail/futex.hpp @@ -12,6 +12,10 @@ #include <boost/fiber/detail/config.hpp> +#ifndef SYS_futex +#define SYS_futex SYS_futex_time64 +#endif + #if BOOST_OS_LINUX extern "C" { #include <linux/futex.h> -- 2.35.1

1 0

unordered_map implementation
by Peter Dimov 19 Feb '22

19 Feb '22

I've been helping Christian Mazakas maintain Unordered, and we've been looking into trying to improve its performance on the synthetic benchmarks we have for it (https://github.com/boostorg/unordered/tree/develop/benchmark) One of the things that are hurting us is that we need to do a double indirection in order to find an element, because Unordered uses a singly-linked list for all its nodes, with the bucket array pointing at the element before the first one (in order to be able to support erasing.) There's also the option of using a doubly-linked list, which however increases the memory footprint. I'm looking at the iterator invalidation rules for std::unordered_map, and iterators are invalidated on every rehash. This makes me wonder why is it necessary to have all the elements in a single list, as every implementation seems to do. It seems to me that it's possible to just have singly- linked lists for each bucket, and then have a "fat" iterator that contains the bucket index and the pointer to the element. On increment, when the end of the bucket list is reached, the iterator can just go to the next non-empty bucket. Is there something I'm missing in the requirements that renders this implementation non-conforming?

2 2

std::launder and its usage in Boost
by Mikhail Kremniov 18 Feb '22

18 Feb '22

Hi, Initially, I posted this question to the boost-users list, but then I was advised to repost it here. I wonder, what is the Boost community's opinion of std::launder? In particular, of its necessity when accessing an object that was created via placement-new in an aligned_storage. As I can see, it's used by Boost.Beast in its implementation of the variant type, but not in other parts of Boost. The reason I'm asking this is that I'm working on a C++14 code-base that uses Boost.Variant and Boost.Optional extensively (as well as other parts of Boost that use Variant and Optional internally). Now we're trying to switch to C++17 at least, and I worry whether it could potentially break things. To put things into context, C++ standard states in the [basic.life] section that if you had an object and then created a new one in the same location, you can use the pointer to the old object to refer to the new one only if (among other things) "the new object is of the same type as the original object (ignoring the top-level cv-qualifiers)". This means, as I understand it, that it's technically illegal to reinterpret_cast the pointer to aligned_storage to the pointer to the actual type of the object created via placement-new, because placement-new has already ended the lifetime of the aligned_storage object. So, implementations of Boost.Optional and Boost.Variant are illegal then (?). But it's been like that since C++03 and Boost worked fine all that time, so it looks like this UB existed only "on paper". But C++17 then added "Note: If these conditions are not met, a pointer to the new object can be obtained from a pointer that represents the address of its storage by calling std::launder". So now the language has the ability to deal with that UB, and a question arises, is it possible that compilers could start to use the UB to perform additional optimizations and make it a real UB? Also, I've seen a couple of times on stackoverflow.com people saying that it's actually fine to reinterpret_cast the storage in C++14, but in C++17 it's not (they didn't explain why though). So, can switching from -std=c++14 to -std=c++17 be a breaking change when using Boost? The fact that Boost.Variant and Boost.Optional don't use std::launder - is it an oversight or a conscious decision? Regards, Mikhail.

5 18

Diagnostic improvements in 1.78/1.79
by Peter Dimov 15 Feb '22

15 Feb '22

This is a quick summary of some 1.78 and 1.79 changes in Assert, ThrowException, and System related to error reporting. In Boost 1.73, Assert acquired a new component, boost::source_location. This is a class encapsulating a source location (a collection of source file name, line number, column, and function name) that is modeled after C++20's std::source_location, except of course it doesn't require C++20. In 1.79, the macro that creates the current source location, BOOST_CURRENT_LOCATION, is now usable in a function default argument, similarly to std::source_location::current(). This enables functions to be declared like this: T& my_vector::at( size_t i, boost::source_location const& loc = BOOST_CURRENT_LOCATION ) { if( i >= size() ) { boost::throw_exception( std::out_of_range( "at" ), loc ); } return data_[ i ]; } Since functions such as `at` are called from many places in the program, it's more useful for the source location in the thrown exception to point at the call site, rather than inside of `at` (which doesn't provide much information.) See for example https://godbolt.org/z/6o9e187a1. Note that the location returned by diagnostic_information(x) points to line 35, which is the call to `v.at(5);` inside `main`. Recommendation one: add source_location default arguments to your throwing functions so that the information logged at the catch site points to the call that threw. In case you find boost::throw_exception too heavyweight, as it adds a boost::exception base class and support for boost::exception_ptr, and this would prevent you from applying the technique above, there is now an alternative function, boost::throw_with_location, in <boost/throw_exception.hpp>. It doesn't integrate with Boost.Exception or boost::exception_ptr, but does add a source location to the exception that can later be retrieved with boost::get_throw_location(x). The above example using boost::throw_with_location can be seen at https://godbolt.org/z/Pcj1xad3v. In 1.78, boost::system::error_code had also acquired support for source locations, although it's not as automatic as the above technique where the default argument automatically adds a location without the user needing to do anything. Since there's no space in error_code for the entire boost::source_location struct, it can only store a pointer to it. This requires the following incantation BOOST_STATIC_CONSTEXPR boost::source_location loc = BOOST_CURRENT_LOCATION; ec.assign( ENOENT, boost::system::generic_category(), &loc ); which can be wrapped in a macro. See the documentation of Boost.System: https://www.boost.org/doc/libs/1_78_0/libs/system/doc/html/system.html#usag… Unlike the case with exceptions, when working with error codes, the situation is reversed and we want to store the source location immediately after discovering the error, rather than the one of the user call that failed. That's both because this location gives the most information as to the source of the error (ENOENT on its own doesn't say much), and because error codes are generally checked close to the user call, so the call location isn't as useful. Recommendation two: add source locations to your error_codes if using Boost.System. Finally, when providing dual APIs, that is, APIs that can signal an error using both error_code or by throwing an exception, you can combine the above two approaches and store both the "deep" source location in the error_code and the "shallow" (user call) location in the system_error exception. I hope you find those useful. Further reading: https://www.boost.org/doc/libs/develop/libs/assert/doc/html/assert.html#sou… https://www.boost.org/doc/libs/develop/libs/throw_exception/doc/html/throw_… https://www.boost.org/doc/libs/develop/libs/system/doc/html/system.html

6 33

Proposed BoostBook fix for invalid <h7> and <h8> elements
by Evan Lenz 14 Feb '22

14 Feb '22

Hello, The DocBook stylesheets used by BoostBook occasionally will output invalid heading elements (<h7> or <h8>). Some (but not all!) areas of the stylesheets properly cap the output to <h6>. In particular, the rule for <bridgehead> fails to do this. The consequences are described in this BoostBook issue: https://github.com/boostorg/boostbook/issues/12 And (originally) in this issue in the docca tool, which depends on BoostBook: https://github.com/boostorg/docca/issues/79 I have created a pull request that fixes the DocBook issue by overriding the bridgehead rule. Although the ideal fix would be in the DocBook stylesheets themselves, these stylesheets are no longer being regularly updated. Also, my proposed fix conforms to the pattern of other BoostBook-specific stylesheet overrides. Is there someone familiar with BoostBook who would be willing to review my pull request (and raise any questions or concerns as desired)? https://github.com/boostorg/boostbook/pull/13 Thanks very much for your time! Evan Lenz

3 3

Building Boost, eventually
by Alain O' Miniussi 09 Feb '22

09 Feb '22

Hi, I finally got some time time to work on a Boost library and I am, as usual, fighting with bjam. === 14:58:08 [alainm@pollux boost]# ./bootstrap.sh --with-toolset=intel-linux Building B2 engine.. ... icpx (ICX) 2021.1 Beta 20200304 # why not icpc ? ... > icpx -x c++ -std=c++11 -O3 -s -static -DNDEBUG .... -o b2 ld: cannot find -lstdc++ ld: cannot find -lstdc++ === The problem here is the -static option, as libstdc++ is not available as an archive on linux (not on the ones I use). I submitted a fix, with no effect: https://github.com/bfgroup/b2/pull/133/files Also apparently some good soul (thank you!) started working on a CMake alternative that just work (checked twice). Its only issue is that the tests don't seems to have moved to CMake. So my question is: 1) Am I better off trying to port the testing of Boost.MPI to CMake and just forget about bjam or, 2) Try to invoke some demonic entity to get bjam working with intel-linux. What is the recommended build method recommended for libraries developers at this point ? Best regards ---- Alain Miniussi DSI, Pôles Calcul et Genie Log. Observatoire de la Côte d'Azur Tél. : +33492003009 (Mont-Gros) +33483618544 (Sophia Antipolis) +33609650665

3 4

boost::throw_exception potential changes
by Peter Dimov 07 Feb '22

07 Feb '22

Currently, `boost::throw_exception(x)` automatically throws an exception derived from `x` that (1) injects a boost::exception base class if there's none, and (2) injects a base class that enables boost::exception_ptr support (boost::current_exception and boost::rethrow_exception.) This is convenient, but the downside is the amount of generated code, e.g. https://godbolt.org/z/5T8T8GEqP (422 lines) compared to https://godbolt.org/z/1zr1odf7n (36 lines.) This is not the end of the world as this code is only generated once per exception type, not on every call to throw_exception, but it's still unpleasant to see. It so happens that boost::exception_ptr has recently acquired the ability to work under C++11 without the need for the supporting base class, by using the standard std::exception_ptr infrastructure. So if we also remove the automatic injection of boost::exception as a base class, and ask users to derive their exceptions from it if they desire having it as a base, it's possible to simplify boost::throw_exception considerably. The normal call now can be almost the same as the naked throw, https://godbolt.org/z/WssWzfrfW (47 lines.) And if BOOST_THROW_EXCEPTION is used, which still adds the source location (file/line/function) to the exception, the result is 97 lines. (https://godbolt.org/z/nETnqrsx8) However, there is a downside. Due to the way std::exception_ptr works under GCC/Clang (and all compilers using the same ABI), the exception is never copied, not when it's captured with std::current_exception (and consequently boost::current_exception), nor when it's rethrown with boost/std::rethrow_exception. This causes problems if an exception is captured, rethrown, caught and modified, then rethrown again using the same exception_ptr. The second rethrow throws the modified exception. This problem can be seen in https://godbolt.org/z/K9eh71ovP. So... what do we do? Should I go ahead with these changes to throw_exception (having a macro to revert to the old behavior, of course)? Or is that too much of a break? We can of course offer the same functionality as part of Boost.Exception, like boost::exception::raise, or similar, but would that be enough to offset the inconvenience?

4 11

[concept_check][ublas] Fixing deprecated copy warnings
by Antony Polukhin 07 Feb '22

07 Feb '22

Hi, There are two PR that fix deprecated copy warnings for GCC and Clang: * https://github.com/boostorg/concept_check/pull/35 * https://github.com/boostorg/ublas/pull/153 Please review those. They make the intent explicit and the code becomes more portable. Trivial sample that causes the warning https://godbolt.org/z/YaPvGfedv -- Best regards, Antony Polukhin

1 0

Primary test compilers in Boost release notes
by Peter Dimov 01 Feb '22

01 Feb '22

We have an issue, https://github.com/boostorg/boost/issues/610, that points out that the "Primary test compilers" section in the Boost 1.78 release notes is misleading, because it doesn't actually reflect whether a Boost library works with a specific compiler or not. The specific example cited is Multiprecision. The release notes say that on Linux, the following C++11 GCC compilers are "primary": GCC, C++11: 4.7.3, 4.8.5, 11 However, Multiprecision doesn't work with GCC 4.7.3 or 4.8.5, and likely never will, because these compilers do not actually implement the C++11 standard. (They don't implement reference qualified member functions and don't have a conforming <type_traits> header.) It would be better for everyone involved if the primary test compilers are somewhat aligned with (a) what Boost libraries actually support or require, and (b) what Boost libraries actually test with. The section historically lists what's in our test matrix, but nowadays most libraries depend on CI for testing, specifically on Github Actions (after the untimely death of open source Travis) and Appveyor. There's a fair bit of discussion in the linked issue above, but what I think is reasonable to list as primary test compilers as far as GCC is concerned is something like C++03: 4.8, 4.9, 5 C++11: 4.8(*), 4.9(*), 5 I would start with 4.8, because this is what GHA has on its 18.04 image. C++03 needs to have GCC up to 5 because this is the default -std level for these versions (GCC 6 is -std=c++14 by default), and the system- provided Boost is compiled with the default. 4.8 has enough of C++11 so it's possible for C++11 libraries to support it without much heroics, but we could go either way on this one, hence the asterisk.

2 1

[GSoC 2022] [Graph] Potential mentors
by Dev Jain 15 Jan '22

15 Jan '22

Hello everyone. I am Dev Jain, a sophomore student pursuing a Bachelors in Computer Science and Engineering from IIT Jammu. I am passionate about discrete mathematics, and in particular graph theory and graph algorithms. I would like to contribute to the Boost Graph Library. I can't find any project ideas for the BGL in recent years of GSoC. Are there any people active with BGL, and any prospective mentors? I understand that, it is recommended to come to the mailing list asking for mentors by describing an idea, but I wanted to ask this since for many years a BGL project hasn't been proposed in the ideas list. Thanks.

1 0

Does anybody know why boost::array does not support multiple dimensions?
by Ivan Matek 10 Jan '22

10 Jan '22

I don't know much about library development, but with variadic templates does not seem so hard, although every library development is much harder than regular user code. Sure boost::array probably wants to support ancient compilers, but variadic version could exist only for "modern"(I do not consider >10y old standards modern) C++. I found this std:: proposal http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2013/n3794.html#Ch05 from 9 y ago, also author seemed to have some working impl on github https://github.com/CTMacUser/ArrayMD/tree/master/include/boost/container But I guess none of it ever progressed. Does anybody knows more about this? It is not trivial since there are probably a ton of edge cases, typdefs, semantics(what should size return?, I would say array of dims) to deal with, but I think it would be a nice extension since I find nested std::array hideous (with current syntax), e.g.: std::array<std::array<int,3>, 4> arr; I would like to have this boost::array<int,4,3> arr; P.S. I know I can use Eigen or some other library, but I think if not std then at least boost should support simple way to have multidim arrays.

10 35

Error with geometry buffer?
by KL 10 Jan '22

10 Jan '22

Hi, Boost Geometry 1.78, linux Â I was getting bad results with my calculations so I decided to narrow down the implementation up to the point I got the following problematic code: Â typedef boost::geometry::model::point <double, 2, boost::geometry::cs::cartesian> Vector2d; Â int main (){ Â Â Â Â Â Â Â Â multi_polygon <polygon <Vector2d> > mp; Â Â Â Â Â Â Â Â /*{ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â polygon <Vector2d> poly; Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â poly.outer().push_back( {0, 0} ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â poly.outer().push_back( {0, 4} ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â poly.outer().push_back( {4, 4} ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â poly.outer().push_back( {4, 0} ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â correct( poly ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â mp.push_back(poly); Â Â Â Â Â Â Â }*/ Â Â Â Â Â Â Â { Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â polygon <Vector2d> poly; Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â poly.outer().push_back( {10, -1} ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â poly.outer().push_back( {14, -1} ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â poly.outer().push_back( {10, -2} ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â poly.outer().push_back( {14, -2}Â ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â correct( poly ); Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â mp.push_back(poly); Â Â Â Â Â Â Â } Â Â Â Â Â Â Â Â Â boost::geometry::strategy::buffer::join_miter join_strategy; Â Â Â Â Â Â Â boost::geometry::strategy::buffer::end_flat end_strategy; Â Â Â Â Â Â Â boost::geometry::strategy::buffer::side_straight side_strategy; Â Â Â Â Â Â Â boost::geometry::strategy::buffer::point_square point_strategy; Â Â Â Â Â Â Â Â boost::geometry::strategy::buffer::distance_symmetric <double> distance_strategy( 2 ); Â Â Â Â Â Â Â boost::geometry::model::multi_polygon <polygon <Vector2d> > result; Â Â Â Â Â Â Â Â boost::geometry::buffer( mp, result, distance_strategy, side_strategy, join_strategy, end_strategy, point_strategy ); Â Â Â Â Â Â Â Â cout << dsv( result ) << endl; Â Â Â Â Â Â Â Â return 0; Â } Â and the result I get is: ((((13.7169, -3.13232), (13.5149, -3.94029), (12, -3.56155), (10.4851, -3.94029), (10.2831, -3.13232), (9.51493, -2.94029), (0.0749244, 0.221833), (10, 1), (14, 1), (23.9251, 0.221833), (14.4851, -2.94029), (13.7169, -3.13232)))) Â Notice the two points: (0.0749244, 0.221833) and (23.9251, 0.221833) Â I have multiple complex (concave) shapes which behave worse than that simple rectangle. But it is a starting point here. Â Did I do something wrong? I need to get my job done, any alternative or helping code massaging ? Â Thanks --Â MKL Â

1 0

[ASIO] Need help reading the documentation
by Andrzej Krzemienski 01 Jan '22

01 Jan '22

Hi Everyone, I need some help in reading the ASIO docs. I am looking at the following example from the docs https://www.boost.org/doc/libs/1_78_0/doc/html/boost_asio/example/cpp17/cor… It calls one of the overloads of async_write in line co_await async_write(socket, boost::asio::buffer(data, n), use_awaitable); The reference section lists eight overloads: https://www.boost.org/doc/libs/1_78_0/doc/html/boost_asio/reference/async_w… But it is still impossible for me to figure out which one it is. `use_awaitable` is documented as "completion token" in https://www.boost.org/doc/libs/1_78_0/doc/html/boost_asio/reference/use_awa… There is some mention of completion token at https://www.boost.org/doc/libs/1_78_0/doc/html/boost_asio/reference/asynchr… So I would expect the name `CompletionToken` to appear in the documentation of `async_write`. Am I missing something? Regards, &rzej;

2 1

[ASIO] Do I have to use shared_ptrs with ASIO?
by Andrzej Krzemienski 29 Dec '21

29 Dec '21

Hi Everyone, I am looking at an example implementation of an asynchronous TCP echo server in Boost.ASIO library: https://www.boost.org/doc/libs/1_77_0/doc/html/boost_asio/example/cpp11/ech… It uses a shared_ptr in the implementation to store the things related to session: socket handle, data buffers. I tried to modify it in a number of ways to avoid the usage of shared_ptr (and any form of shared ownership), but they all failed. It looks like I have to use a shared_pointer (or equivalent) when I use ASIO sockets. But conceptually, there is never a point in time where two tasks have to access members of this `session` concurrently: they are always sequenced. So, at least conceptually, there should be a way to do this with a session type that is only movable, with unique ownership: a task does its job with the session and then moves it to the subsequent task. So is this necessity to use a shared pointer an unnecessary and suboptimal design choice? Or is there something fundamental that prevents the unique ownership of buffers and socket handles? Or maybe is there a way to do it in ASIO that I overlooked? I am not trying to solve any specific problem. It just strikes me that a shared_ptr is used in a demo example for the library. I was always of the opinion that a shared_ptr is often abused as a way of doing an ad-hoc GC. Regards, &rzej;

8 21

Seeking help for kickstart
by Rahul Sharma 23 Dec '21

23 Dec '21

Hello everyone, I read all the information given on the blog pages and websites sent to me via email which I received when I subscribed to this mailing list, but I am too confused and I am not able to figure out from where to start and how to find some beginner friendly issues and projects to work on. Hoping for help and guidance to kickstart this journey. Accept my apologies if this is not the proper way to communicate about such problems. Sent from [1]Mail for Windows References 1. https://go.microsoft.com/fwlink/?LinkId=550986

1 0

To contribute to this community.
by Rahul Sharma 22 Dec '21

22 Dec '21

Hello everyone, I am Rahul Sharma currently a sophomore at IIT Guwahati pursuing my B.Tech with major in Civil Engineering. I am very much enthusiastically inclined towards technology and want to pursue my carrier in the field of technology. And also I am very much interested in the open source communities and would really like to be part of such a community and to work with other peers with the same vision and to work with dedication on some really cool real world projects. My tech stack comprises of programming languages like c and c++ and am also a front end web developer and currently learning the back end web development with react. Seeking for the guidance from the other experienced peer developers and mentors. Sent from [1]Mail for Windows References 1. https://go.microsoft.com/fwlink/?LinkId=550986

2 1

[release] Boost 1.78.0
by Marshall Clow 09 Dec '21

09 Dec '21

Release 1.78.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains numerous enhancements and bug fixes for existing libraries. For details, including download links, see <http://www.boost.org/users/news/version_1.78.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.78.0/> To install this release on your system, see <http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. Thanks, -- The Boost Release Team Marshall Clow, Michael Caisse, Glen Fernandes

3 2

[release] Master branch is now open for merging
by Marshall Clow 08 Dec '21

08 Dec '21

No restrictions; the release calendar is up to date. https://boost.org/development Next milestone: 23-Feb Boost 1.79.0 closed for new libraries and breaking changes — Marshall

1 0

boost.spawn: review requested
by Oliver Kowalke 06 Dec '21

06 Dec '21

Hi, I'd like to propose the new library boost.spawn (https://olk.github.io/) for review. boost.asio's boost::asio::spawn() uses the deprecated and inefficient boost.coroutine library. boost.spawn provides the same functionality while using boost.context's fiber directly. Oliver

12 49

Boost::any typecasting issue(bad_any_cast)
by Daggumati, Rajesh 05 Dec '21

05 Dec '21

Hi Team, While doing typecasting from boost::any to DecodeErrorPayload_t, its throwing bad_any_cast .. class RegisterIONotification { public: enum NotifyType { TypeUnknown, TypeRegTx, TypeRegRx, TypeDecodeError }; NotifyType Type; boost::any Payload; typedef boost::tuple<std::string, BinaryBuffer_t> DecodeErrorPayload_t; RegisterIONotification(NotifyType type;,boost::any payload) { Type(type); Payload(payload); } }; I have called RegisterIONotification from other class function. void RegisterIOThreaded::OnDecodeError( const std::string& error, BinaryBuffer_t data ) { RegisterIONotification notify(RegisterIONotification::TypeDecodeError ,make_tuple(error, data)); ..... .... ... } While testing, I am getting bad_any_cast exception. TEST_F(...,...) { RegisterIONotification notify = sink.GetDataById(ID::NOTIFY_COMMS_STATUS, 0).GetValue<RegisterIONotification>(); ASSERT_EQ(RegisterIONotification::TypeDecodeError, notify.Type); //passed RegisterIONotification::DecodeErrorPayload_t payload; ASSERT_NO_THROW(payload = boost::any_cast<RegisterIONotification::DecodeErrorPayload_t>(notify.Payload));// Here its got failed...Please help me to fix this. } Regards, Rajesh D Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.

3 2

[release] Boost 1.78.0 Release Candidate 1
by Marshall Clow 03 Dec '21

03 Dec '21

The first release candidates for the 1.78.0 release are now available at: <https://boostorg.jfrog.io/artifactory/main/release/1.78.0/source/> The SHA256 checksums are as follows: 94ced8b72956591c4775ae2207a9763d3600b30d9d7446562c552f0a14a63be7 boost_1_78_0_rc1.tar.gz f22143b5528e081123c3c5ed437e92f648fe69748e95fa6e2bd41484e2986cc3 boost_1_78_0_rc1.zip 090cefea470bca990fa3f3ed793d865389426915b37a2a3258524a7258f0790c boost_1_78_0_rc1.7z 8681f175d4bdb26c52222665793eef08490d7758529330f98d3b29dd0735bccc boost_1_78_0_rc1.tar.bz2 As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

3 3

[release] Master branch now closed for 1.78.0 release
by Marshall Clow 02 Dec '21

02 Dec '21

Please do not make any commits to the master branch. — Marshall

1 0

[release] 1.78.0 post-beta merges
by Marshall Clow 01 Dec '21

01 Dec '21

The master branch is is now open for post-beta merges, but only as described in the Post-Beta Merge Policy. See <https://github.com/boostorg/wiki/wiki/Releases%3A-Beta-Merge-Policy <https://github.com/boostorg/wiki/wiki/Releases%3A-Beta-Merge-Policy>> Reminder: The master branch closes for the release on Wednesday, December 1st. Full calendar here: https://www.boost.org/development/ <https://www.boost.org/development/> — Marshall P.S Doc changes and test changes do NOT require release manager approval to be merged.

11 36

[Release] The release branch will close for the 1.78.0 release TOMORROW
by Marshall Clow 01 Dec '21

01 Dec '21

As always, calendar is here: https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> — Marshall

1 0

Re: [boost] boost.spawn: review requested
by Boris Kolpackov 30 Nov '21

30 Nov '21

Oliver Kowalke <oliver.kowalke(a)gmail.com> writes: > Am Mo., 29. Nov. 2021 um 15:54 Uhr schrieb Boris Kolpackov < > boris(a)codesynthesis.com>: > > > FWIW (and I may be out of context), but "spawn" seems like a > > too generic of a name. I, for example, thought this is about > > posix_spawn(). Maybe call it spawn_fiber or some such? > > > > boost.asio named the function spawn() - boost.spawn named it spawn_fiber() Sorry, looks I wasn't clear enough: I am talking about the library name being too generic: Boost.Spawn can mean spawning all kinds of things (processes, threads, fibers, etc). The fact that you called the function spawn_fiber() in a sense confirms this.

1 0

[fusion] add support for view construction from movable view
by herve martin 28 Nov '21

28 Nov '21

Hi, When working with view of boost::fusion I feel something frustrated because of the limited set of possible constructors. Indeed, apart from copy constructor, views usually only provide constructors taken l-value reference on sequence as input. I would like to extend the constructors set of views with some new ones which would also accept r-value references on view as input. This would allow some fancy combination at construction time as for example: vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><bool> v0(true);vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><int, char> v1(3, 'x');vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><std::string, int> v2("hello", 123); using view1 = joint_view< vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><int, char> , vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><std::string, int>>;using view = joint_view< vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><bool> , view1>; view aview = view(v0, view1(v1, v2));std::cout << aview << std::endl; I would be glad to contribute to the boost library by updating the boost::fusion views with some new constructors bu I'm not familiar with development in boost. What would be the next step to give a chance to my proposal to integrate boost ? Best regards, Herve

1 0

Adding my sorting algorithm, ska_sort, to boost, attempt 2
by Malte Skarupke 24 Nov '21

24 Nov '21

Hi everyone, I started a discussion about this in October, but at the time the maintainer of the sort library was busy, then I was busy, so now it's January... I wrote a generalized version of radix sort a couple years ago and gave a talk about it here: https://www.youtube.com/watch?v=zqs87a_7zxw I would like to get a new version of that sorting algorithm into boost. It's faster than what I showed several years ago. It's also even more general and has a new interface that should be easier to extend. I uploaded the code here: https://github.com/skarupke/sort/tree/master The documentation is also already updated with new benchmark results. Let me know what's required to get this into boost. Would you like this in the form of a pull request? One of the big things that probably needs review is the interface, since radix sorting works differently than comparison based sorting. For most normal uses you just need to provide a sort key, but more complicated cases can get more complicated. I tried very hard to make everything easy, but I'd also be curious if others can come up with better ways of doing the interface. Thanks, Malte -- Malte Skarupke malteskarupke(a)fastmail.fm

8 10

[release] 1.78.0 post-beta merges
by Oliver Kowalke 20 Nov '21

20 Nov '21

Hi, I'd like to merge several fixes for boost.context, boost.coroutine, boost.coroutine2 and boost.fiber to branch master. Oliver

2 1

Boost::any bad_any_cast issue
by rajesh daggumati 18 Nov '21

18 Nov '21

Hi Team, While doing typecasting from boost::any to DecodeErrorPayload_t, its throwing bad_any_cast .. class RegisterIONotification { public: enum NotifyType { TypeUnknown, TypeRegTx, TypeRegRx, TypeDecodeError }; NotifyType Type; boost::any Payload; typedef boost::tuple<std::string, BinaryBuffer_t> DecodeErrorPayload_t; RegisterIONotification(NotifyType type;,boost::any payload) { Type(type); Payload(payload); } }; I have called RegisterIONotification from other class function. void RegisterIOThreaded::OnDecodeError( const std::string& error, BinaryBuffer_t data ) { RegisterIONotification notify(RegisterIONotification::TypeDecodeError ,make_tuple(error, data)); ..... .... ... } While testing, I am getting bad_any_cast exception. TEST_F(...,...) { RegisterIONotification notify = sink.GetDataById(ID::NOTIFY_COMMS_STATUS, 0).GetValue<RegisterIONotification>(); ASSERT_EQ(RegisterIONotification::TypeDecodeError, notify.Type); //passed RegisterIONotification::DecodeErrorPayload_t payload; ASSERT_NO_THROW(payload = boost::any_cast<RegisterIONotification::DecodeErrorPayload_t>(notify.Payload));// Here its got failed…Please help me to fix this. } Regards, Rajesh D

2 1

ASIO problem with boost 1.78.0.beta1 ?
by Stefan Heinzmann 13 Nov '21

13 Nov '21

Hi all, I'm observing a problem with boost::asio that has surfaced with the newest beta relative to version 1.77.0, using MSVC 16.11.6. I'm getting the following errors: 1>...src\libs\asio\include\boost/asio/impl/any_io_executor.ipp(26,18): error C2039: 'any_io_executor': is not a member of 'boost::asio::executor' 1>...src\libs\asio\include\boost/asio/executor.hpp(48): message : see declaration of 'boost::asio::executor' 1>...src\libs\asio\include\boost/asio/impl/any_io_executor.ipp(26,34): error C2059: syntax error: ')' 1>...src\libs\asio\include\boost/asio/impl/any_io_executor.ipp(28,1): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int ...and so on. The errors seem rather weird to me, so I might be doing something wrong myself, but the exact same code compiles fine with 1.77.0, using the same compiler. Has anyone got an idea what's wrong? Should I raise an issue in github? Cheers Stefan Heinzmann

1 1

union support in describe
by Gero Peterhoff 12 Nov '21

12 Nov '21

Hello, first of all, thank you very much for the great work. But I miss the support for unions. Is that correct? namespace boost { namespace describe { #define BOOST_DESCRIBE_UNION(C, Public) \ static_assert(std::is_union<C>::value, "BOOST_DESCRIBE_UNION should only be used with union types"); \ BOOST_DESCRIBE_PUBLIC_MEMBERS_(C BOOST_DESCRIBE_PP_UNPACK Public) \ BOOST_DESCRIBE_PROTECTED_MEMBERS_(C) \ BOOST_DESCRIBE_PRIVATE_MEMBERS_(C) } // describe } // boost This version only supports public members. I also miss the support for std::get. Is that correct? namespace boost { namespace describe { #define BOOST_DESCRIBE_GET(C) \ template <std::size_t Index> \ inline constexpr const auto& get(const C& arg) noexcept \ { \ static_assert(std::is_class<C>::value || std::is_union<C>::value, "BOOST_DESCRIBE_GET should only be used with class, struct or union types"); \ using members = boost::describe::describe_members<C, boost::describe::mod_any_access>; \ static_assert(Index < boost::mp11::mp_size<members>()); \ return arg.*boost::mp11::mp_at_c<members, Index>().pointer; \ } \ template <std::size_t Index> \ inline constexpr auto& get(C& arg) noexcept \ { \ static_assert(std::is_class<C>::value || std::is_union<C>::value, "BOOST_DESCRIBE_GET should only be used with class, struct or union types"); \ using members = boost::describe::describe_members<C, boost::describe::mod_any_access>; \ static_assert(Index < boost::mp11::mp_size<members>()); \ return arg.*boost::mp11::mp_at_c<members, Index>().pointer; \ } } // describe } // boost However, the access rights are not taken into account. E.g.: struct A { int i; float f; }; BOOST_DESCRIBE_STRUCT(A, (), (i, f)) namespace std { BOOST_DESCRIBE_GET(A) } // std This also solves a very special problem, provided the compiler supports it: active member of a constexp union. Problem: union U { int64_t i; double d; }; constexpr U u{.d{3.1415}}; constexpr auto i=u.i; -> error In short: namespace std { template <typename Type> inline constexpr bool is_constant_initialized(const Type& arg) noexcept { #if __has_builtin(__builtin_constant_p) return __builtin_constant_p(arg); #elif defined(BOOST_MSVC) ??? #else static_assert(false, "is_constant_initialized not supportet"); return false; #endif } template <typename Type> inline constexpr bool is_constant_initialized_front(const Type& arg) noexcept { return is_constant_initialized(arg); } template <typename Type, size_t Size> inline constexpr bool is_constant_initialized_front(const Type(&arg)[Size]) noexcept { static_assert(Size > 0); return is_constant_initialized(arg[0]); } template <typename Type, size_t Size> inline constexpr bool is_constant_initialized_front(const std::array<Type, Size>& arg) noexcept { static_assert(Size > 0); return is_constant_initialized(arg[0]); } } // std namespace boost { namespace describe { template <typename Type> inline constexpr std::size_t active_index(const Type& arg) noexcept { static_assert(std::is_union_v<Type>); using any = describe_members<Type, mod_any_access>; std::size_t result{0}, index{0}; bool first{true}; boost::mp11::mp_for_each<any>([&](const auto& desc) constexpr noexcept { const auto& elem{arg.*desc.pointer}; if (std::is_constant_initialized_front(elem)) { if (first) { first = false; result = index; } } ++index; }); return first ? 0 : result; } template <auto Value> inline constexpr std::size_t active_index_v = std::integral_constant<std::size_t, active_index(Value)>::value; } // describe } // boost union __mm128_emu { float m128_f32[4]; double m128_f64[2]; int64_t m128_i64[2]; int32_t m128_i32[4]; int16_t m128_i16[8]; int8_t m128_i8[16]; uint64_t m128_u64[2]; uint32_t m128_u32[4]; uint16_t m128_u16[8]; uint8_t m128_u8[16]; }; BOOST_DESCRIBE_UNION(__mm128_emu, (m128_f32, m128_f64, m128_i64, m128_i32, m128_i16, m128_i8, m128_u64, m128_u32, m128_u16, m128_u8)) namespace std { BOOST_DESCRIBE_GET(__mm128_emu) } // std constexpr __mm128_emu m128{.m128_u32{4711}}; constexpr auto arr = std::to_array(std::get<boost::describe::active_index_v<m128>>(m128)); // works with gcc, clang, intel Do you have an idea how to implement __builtin_constant_p for all compilers? thx Gero

2 2

Update on the 1.78.0 beta
by Marshall Clow 11 Nov '21

11 Nov '21

The beta was supposed to be released yesterday. It’s done, but there’s an issue on Jfrog that seems to make it hard to download. I’m talking to the JFrog folks to get this resolved, and when that’s done, I’ll announce that the beta is released. — Marshall

1 0

[release] Boost 1.78.0 Beta 1 Release Candidate 1 is available
by Marshall Clow 09 Nov '21

09 Nov '21

The first release candidates for the 1.78.0 beta release are now available at: <https://boostorg.jfrog.io/ui/native/main/beta/1.78.0.beta1/source <https://boostorg.jfrog.io/ui/native/main/beta/1.78.0.beta1/source>> The SHA256 checksums are as follows: 7a3a025451dfa2923129214eef7d16b03c02310a353d02158a549f6caa4284b0 boost_1_78_0_b1_rc1.tar.bz2 c491b1dcb916195598aa6581d6708d57fcc750516641c22511c088d572de9c07 boost_1_78_0_b1_rc1.tar.gz 35e7a3b0eb412a3933e57c72ba96374eb7d88ff1f89dbec62a16d67ffea2105a boost_1_78_0_b1_rc1.7z e6b68feb2f63401c96ca9fe25e939b409189fbe526a6e784e4bd69832c8f09cb boost_1_78_0_b1_rc1.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

3 5

How to get started with contribution
by Anmol Singh 09 Nov '21

09 Nov '21

Respected Sir/Madam, I am Anmol Singh, an Information Technology undergrad. I have just entered my second year at ADGITM, IP University. I am new to open source contributions but I am well aware of C++,C and javascript. I would love to contribute to your organisation but could you please tell me how to get started? Regards Anmol

1 0

conversion of catched exception to shared_ptr
by rajesh daggumati 08 Nov '21

08 Nov '21

rajesh daggumati <rajeshdaggumati9999(a)gmail.com> 09:59 (4 hours ago) to boost-users HI, please help me to solve below issue. Shared pointers are used in my code. class Exception : public virtual std::exception,public virtual boost::exception { --- }; class ExceptionTestException : public Exception { --- }; boost::shared_ptr<Exception> exceptionptr_t; try { Boost_Throw_function(ExceptionTestException("Hiii")); } catch(...) { boost::exception_ptr exceptionptr = boost::current_exception(); try { boost::rethrow(exceptionptr) } catch(boost::exception &e) { //here i need to assign this 'e' to shared pointer but this e is not in heap so then how to assign this e to sharedptr(exceptionptr_t). 1 way is : boost::exception *ep = new ExceptionTestException(e); exceptionptr_t(ep); here we know that exception_ptr is having ExceptionTestException but in some cases, we dont know which type of excepiton we have in exception_ptr in runtime. then how to assign to shared_ptr

4 4

Library category error handling
by Emil Dotchevski 07 Nov '21

07 Nov '21

Should we add a formal category for error handling libraries in https://www.boost.org/development/library_metadata.html?

5 6

Does boost have a way to get type name at compile time?
by Ivan Matek 04 Nov '21

04 Nov '21

I am aware of hacks/magic with __PRETTY_FUNCTION__ <https://stackoverflow.com/questions/69624128/parameter-pack-sorting-or-equi…>but I wonder if there is a portable boost way to do that?

2 1

Header-only libraries linking to compiled libraries...
by Peter Dimov 03 Nov '21

03 Nov '21

... create problems (at least) for CMake users, because a project using a header-only library must link to its compiled dependencies by hand. (Important Note: this is not about the CMake build of Boost. It's about the b2 build of Boost, and the CMake configuration files it generates.) Compiled libraries don't have this problem, because they have CMake targets, and linking to the library target automatically links to the dependencies. For instance, linking to Boost::filesystem would automatically link to Boost::atomic (and on Windows, to bcrypt.lib) as needed. However, as pointed out in https://github.com/boostorg/boost_install/issues/54, header-only libraries such as Process or UUID have no CMake targets. Consequently, it's not possible for the CMake project to link to Boost::uuid and automatically inherit the dependency to bcrypt.lib, or to link to Boost::process and automatically acquire a dependency to Boost::filesystem. Since the CMake configuration files that are generated by `b2 install` define CMake targets based on the b2 targets, it's not possible to fix this just on the boost-install side. If we want Boost::process to appear as a target in CMake, we need boost_process to appear as a target in b2, that is, we need libs/process/build/Jamfile to exist. The easiest way to fix it - if we decide to do something about it - is to create dummy compiled libraries for each such header-only library that isn't really header-only because of dependencies. A number of Boost libraries are already header-only with a stub library for backward compatibility (System, DateTime, Regex), so this wouldn't be something novel.

6 17

Reminder: The master branch will be closing for the 1.78.0 beta release TOMORROW
by Marshall Clow 02 Nov '21

02 Nov '21

If you have changes for the beta, they need to be merged to master before the end of day tomorrow. See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release managers

1 0

Boost libraries packaged for build2
by Boris Kolpackov 02 Nov '21

02 Nov '21

We have added support for the build2 build systems to 136 out of 145 Boost libraries and version 1.77.0 is now available from the cppget.org package repository. For details, see: https://build2.org/blog/build2-boost.xhtml Folks on this mailing list may be particularly interested in the "Implementation Details" section where we go deeper into how this conversion was accomplished: https://build2.org/blog/build2-boost.xhtml#impl-details (There is also the README-DEV file in the repository linked from this section which has even more details.) Also, let me add that this is not a call to convert Boost to build2. While we would gladly assist with this effort if the Boost community so wishes, we are also happy to continue our work out of tree.

1 0

boost::trim_copy(boost::string_view()); // error
by Olaf van der Spek 31 Oct '21

31 Oct '21

Hi, Why does the overload for boost::string_view not work? The std one works. Could it be made to work? #include <boost/algorithm/string.hpp> #include <boost/utility/string_ref.hpp> #include <boost/utility/string_view.hpp> #include <iostream> #include <string_view> int main() { boost::trim_copy(boost::string_view()); // error boost::trim_copy(std::string_view()); } $ g++ t0.cpp In file included from /usr/include/boost/algorithm/string.hpp:19, from t0.cpp:1: /usr/include/boost/algorithm/string/trim.hpp: In instantiation of ‘SequenceT boost::algorithm::trim_copy_if(const SequenceT&, PredicateT) [with SequenceT = boost::basic_string_view<char, std::char_traits<char> >; PredicateT = boost::algorithm::detail::is_classifiedF]’: /usr/include/boost/algorithm/string/trim.hpp:343:49: required from ‘SequenceT boost::algorithm::trim_copy(const SequenceT&, const std::locale&) [with SequenceT = boost::basic_string_view<char, std::char_traits<char> >]’ t0.cpp:10:19: required from here /usr/include/boost/algorithm/string/trim.hpp:319:20: error: no matching function for call to ‘boost::basic_string_view<char, std::char_traits<char> >::basic_string_view(const char*, const char*&)’ 319 | return SequenceT( | ^~~~~~~~~~ 320 | detail::trim_begin( | ~~~~~~~~~~~~~~~~~~~ 321 | ::boost::begin(Input), | ~~~~~~~~~~~~~~~~~~~~~~ 322 | TrimEnd, | ~~~~~~~~ 323 | IsSpace), | ~~~~~~~~~ 324 | TrimEnd | ~~~~~~~ 325 | ); | ~ In file included from t0.cpp:3: /usr/include/boost/utility/string_view.hpp:97:9: note: candidate: ‘template<class Allocator> boost::basic_string_view<charT, traits>::basic_string_view(const std::__cxx11::basic_string<charT, traits, Allocator>&) [with Allocator = Allocator; charT = char; traits = std::char_traits<char>]’ 97 | basic_string_view(const std::basic_string<charT, traits, Allocator>& str) BOOST_NOEXCEPT | ^~~~~~~~~~~~~~~~~ /usr/include/boost/utility/string_view.hpp:97:9: note: template argument deduction/substitution failed: In file included from /usr/include/boost/algorithm/string.hpp:19, from t0.cpp:1: /usr/include/boost/algorithm/string/trim.hpp:319:20: note: mismatched types ‘const std::__cxx11::basic_string<char, std::char_traits<char>, Allocator>’ and ‘const char*’ 319 | return SequenceT( | ^~~~~~~~~~ 320 | detail::trim_begin( | ~~~~~~~~~~~~~~~~~~~ 321 | ::boost::begin(Input), | ~~~~~~~~~~~~~~~~~~~~~~ 322 | TrimEnd, | ~~~~~~~~ 323 | IsSpace), | ~~~~~~~~~ 324 | TrimEnd | ~~~~~~~ 325 | ); | ~ In file included from t0.cpp:3: /usr/include/boost/utility/string_view.hpp:110:23: note: candidate: ‘constexpr boost::basic_string_view<charT, traits>::basic_string_view(const charT*, boost::basic_string_view<charT, traits>::size_type) [with charT = char; traits = std::char_traits<char>; boost::basic_string_view<charT, traits>::size_type = long unsigned int]’ (near match) 110 | BOOST_CONSTEXPR basic_string_view(const charT* str, size_type len) | ^~~~~~~~~~~~~~~~~ /usr/include/boost/utility/string_view.hpp:110:23: note: conversion of argument 2 would be ill-formed: In file included from /usr/include/boost/algorithm/string.hpp:19, from t0.cpp:1: /usr/include/boost/algorithm/string/trim.hpp:324:17: error: invalid conversion from ‘boost::range_detail::extract_const_iterator<boost::basic_string_view<char, std::char_traits<char> >, true>::typ’ {aka ‘const char*’} to ‘boost::basic_string_view<char, std::char_traits<char> >::size_type’ {aka ‘long unsigned int’} [-fpermissive] 324 | TrimEnd | ^~~~~~~ | | | boost::range_detail::extract_const_iterator<boost::basic_string_view<char, std::char_traits<char> >, true>::type {aka const char*} In file included from t0.cpp:3: /usr/include/boost/utility/string_view.hpp:107:23: note: candidate: ‘constexpr boost::basic_string_view<charT, traits>::basic_string_view(const charT*) [with charT = char; traits = std::char_traits<char>]’ 107 | BOOST_CONSTEXPR basic_string_view(const charT* str) | ^~~~~~~~~~~~~~~~~ /usr/include/boost/utility/string_view.hpp:107:23: note: candidate expects 1 argument, 2 provided /usr/include/boost/utility/string_view.hpp:78:23: note: candidate: ‘constexpr boost::basic_string_view<charT, traits>::basic_string_view(const boost::basic_string_view<charT, traits>&) [with charT = char; traits = std::char_traits<char>]’ 78 | BOOST_CONSTEXPR basic_string_view(const basic_string_view &rhs) BOOST_NOEXCEPT | ^~~~~~~~~~~~~~~~~ /usr/include/boost/utility/string_view.hpp:78:23: note: candidate expects 1 argument, 2 provided /usr/include/boost/utility/string_view.hpp:73:23: note: candidate: ‘constexpr boost::basic_string_view<charT, traits>::basic_string_view() [with charT = char; traits = std::char_traits<char>]’ 73 | BOOST_CONSTEXPR basic_string_view() BOOST_NOEXCEPT | ^~~~~~~~~~~~~~~~~ /usr/include/boost/utility/string_view.hpp:73:23: note: candidate expects 0 arguments, 2 provided In file included from /usr/include/boost/algorithm/string.hpp:19, from t0.cpp:1: /usr/include/boost/algorithm/string/trim.hpp: In instantiation of ‘SequenceT boost::algorithm::trim_copy_if(const SequenceT&, PredicateT) [with SequenceT = std::basic_string_view<char>; PredicateT = boost::algorithm::detail::is_classifiedF]’: /usr/include/boost/algorithm/string/trim.hpp:343:49: required from ‘SequenceT boost::algorithm::trim_copy(const SequenceT&, const std::locale&) [with SequenceT = std::basic_string_view<char>]’ t0.cpp:11:19: required from here /usr/include/boost/algorithm/string/trim.hpp:324:17: error: invalid conversion from ‘boost::range_detail::extract_const_iterator<std::basic_string_view<char>, true>::type’ {aka ‘const char*’} to ‘std::basic_string_view<char>::size_type’ {aka ‘long unsigned int’} [-fpermissive] 324 | TrimEnd | ^~~~~~~ | | | boost::range_detail::extract_const_iterator<std::basic_string_view<char>, true>::type {aka const char*} In file included from /usr/include/c++/11/bits/basic_string.h:48, from /usr/include/c++/11/string:55, from /usr/include/boost/algorithm/string/std/string_traits.hpp:15, from /usr/include/boost/algorithm/string/std_containers_traits.hpp:19, from /usr/include/boost/algorithm/string.hpp:18, from t0.cpp:1: /usr/include/c++/11/string_view:137:56: note: initializing argument 2 of ‘constexpr std::basic_string_view<_CharT, _Traits>::basic_string_view(const _CharT*, std::basic_string_view<_CharT, _Traits>::size_type) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_string_view<_CharT, _Traits>::size_type = long unsigned int]’ 137 | basic_string_view(const _CharT* __str, size_type __len) noexcept | ~~~~~~~~~~^~~~~ -- Olaf

2 1

VS2022 release date is Nov 8
by Peter Dimov 30 Oct '21

30 Oct '21

The Visual Studio 2022 (msvc-14.3) release date is Nov 8, which is right in the middle of our beta master freeze (Nov 3 - Nov 10). Since VS2022 is now RC2, which means that it won't change much if at all, we probably need to start testing our libraries with it now, so that the issues are ironed out before 1.78 beta.

9 12

The deadline for new libraries and breaking changes in Boost 1.78.0 is Friday, October 29
by Marshall Clow 27 Oct '21

27 Oct '21

Sorry for the late notice; the deadline was supposed to be today, but I'm extending it to Friday. See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar Next deadline: Boost 1.78.0 closed for beta Wednesday, Nov 3, 2021 — The Release Managers

1 0

Header-only Boost.System
by Ashish Singh 25 Oct '21

25 Oct '21

Hi All, In my application, I'm trying to use Boost ASIO via boost 1.66 and defining the following two macros in the Makefile. Basically trying to use the header-only approach. CFLAGS += \ -DBOOST_ERROR_CODE_HEADER_ONLY \ -DBOOST_SYSTEM_NO_DEPRECATED But then I came across this thread: https://lists.boost.org/Archives/boost/2017/10/239106.php "In header only mode, multiple instances may appear and thus no longer be proper singletons. Stuff breaks in this situation, badly." Is the above applicable to 1.66 too?How can I safely use the header-only approach in boost 1.66? Thanks,Ashish

2 8

Boost.URL: Something Wicked This Way Comes! (Was: Needs Review)
by Vinnie Falco 21 Oct '21

21 Oct '21

Folx: Well, I was on a pause but I picked Boost.URL back up and whipped it into shape. The good news, this Belle is ready for the Ball ! I invite you to kick the tires and light the fires on the next major component in my line of network and protocol libraries: Repository <https://github.com/CPPAlliance/url/> Documentation <https://master.url.cpp.al/> Docs are still being worked on, of course (docs are never "done"). `url_view`, `url`, `static_url`, and `authority_view` should be completely solid and ready to get beat up. And I'm ready for all that lovely negative feedback !!! If a kind soul would like to volunteer to be the review manager, that would be swell. I'm very happy to answer any questions about the library, and happy to get feedback regarding the design and implementation. -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

12 79

Opinions on introduction of string_view in Core
by Andrey Semashev 21 Oct '21

21 Oct '21

Hi, Recently, a new implementation of string_view was introduced in Boost.Core: https://github.com/boostorg/core/blob/d5bd40e5280487fb29a108eb42e6c4f0bef69… Most of you probably know there is also a string_view implementation in Boost.Utility: https://github.com/boostorg/utility/blob/05e0d1688dcfcd3fdd65bdb6884b7edd1a… The main motivation for introducing the new implementation is adding conversions to/from std::string_view, which were proposed to Boost.Utility and rejected a while ago: https://github.com/boostorg/utility/pull/51 Another notable deviation of boost::core::string_view from std::string_view and boost::string_view is that it only accepts the character type in template parameters and not char_traits. This choice was made to simplify implementation. I have concerns that introducing yet another string_view type (3rd in Boost, after boost::string_ref and boost::string_view, not counting std::string_view) is not good for the ecosystem and interoperability, as this will require adding explicit support in some code bases. One example that I readilly have is Boost.Log: https://github.com/boostorg/log/blob/4c54e4ca4c31f18ce2e451e8d0abf88054242d… std::string_view was supposed to make user's code simpler by removing the need to provide a multitude of function overloads accepting string arguments. boost::string_view (and boost::string_ref before it) was a prototype implementation before introduction of std::string_view and served a similar purpose. In the age with std::string_view, boost::string_view is still useful as a drop-in replacement for std::string_view to lower C++ requirements in libraries and projects, like this: #if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW) using std::basic_string_view; using std::string_view; using std::string_view; #else using boost::basic_string_view; using boost::string_view; using boost::string_view; #endif Introducing boost::core::string_view, which is not a drop-in replacement, does not make users' code simpler as it requires adding yet another set of overloads and specializations to users' APIs. I should stress that I'm not opposing because I don't want to make changes to Boost.Log, I'm opposing because I don't think those changes will be for the better, and because I view this as potentially destructive to the wide adoption of one common string_view type (be it std::string_view or boost::string_view, depending on the conventions taken in the project) to accept string arguments. Please, express your opinions on this matter, in particular: - Do you think it is good/ok/bad to have yet another string_view in Boost? - Is it ok that boost::core::string_view is not a drop-in replacement for std::string_view? Should it be changed to be one? - Should we, perhaps, do something with boost::string_view from Boost.Utility? Deprecate? - Should we reopen the discussion to add conversion to/from std::string_view to boost::string_view, which led to this fork? Perhaps, hold a vote to make this change as widely requested? - Any other course of action or thoughts? Thanks. PS: This post was made after an initial discussion in this commit: https://github.com/boostorg/core/commit/95924b1329da49e70c9c8485b87e066895d…

12 57

hash_value( complex<T> )
by Peter Dimov 19 Oct '21

19 Oct '21

At the moment, boost::hash_value for complex<T> is specified as When T is a built in type and val.imag() == 0, the result is equal to hash_value(val.real()). Otherwise an unspecified value, except that equal arguments shall yield the same result. This is a bit odd; the natural implementation for a two-argument point/tuple type is std::size_t seed = 0; boost::hash_combine( seed, v.real() ); boost::hash_combine( seed, v.imag() ); return seed; Can anyone offer an opinion on whether or why the original behavior is preferable?

3 6

regarding boost::exception
by rajesh daggumati 18 Oct '21

18 Oct '21

Hi Team, I need to create an object for catched exception . class exception: virtual public std::exception ,virtual public boost::exception {} inside my application code, try{ boost::rethrow_exception(exceptr)} catch(std::exception &e) { std::exception *e = stacktoHeapObject(e); } static std::exception* stacktoHeapObj(std::exception* e) { if (dynamic_cast<std::bad_alloc*>(e)) { return new std::bad_alloc(*(dynamic_cast<std::bad_alloc*>(e))); } else if (dynamic_cast<std::bad_cast*>(e)) { return new std::bad_cast(*(dynamic_cast<std::bad_cast*>(e))); } else if (dynamic_cast<std::bad_typeid*>(e)) { return new std::bad_typeid(*(dynamic_cast<std::bad_typeid*>(e))); } else if (dynamic_cast<std::bad_exception*>(e)) { return new std::bad_exception(*(dynamic_cast<std::bad_exception*>(e))); } else if (dynamic_cast<std::domain_error*>(e)) { return new std::domain_error(*(dynamic_cast<std::domain_error*>(e))); } else if (dynamic_cast<std::invalid_argument*>(e)) { return new std::invalid_argument(*(dynamic_cast<std::invalid_argument*>(e))); } else if (dynamic_cast<std::length_error*>(e)) { return new std::length_error(*(dynamic_cast<std::length_error*>(e))); } else if (dynamic_cast<std::out_of_range*>(e)) { return new std::out_of_range(*(dynamic_cast<std::out_of_range*>(e))); } else if (dynamic_cast<std::overflow_error*>(e)) { return new std::overflow_error(*(dynamic_cast<std::overflow_error*>(e))); } else if (dynamic_cast<std::range_error*>(e)) { return new std::range_error(*(dynamic_cast<std::range_error*>(e))); } else if (dynamic_cast<std::underflow_error*>(e)) { return new std::underflow_error(*(dynamic_cast<std::underflow_error*>(e))); } else if (dynamic_cast<std::runtime_error*>(e)) { return new std::runtime_error(*(dynamic_cast<std::runtime_error*>(e))); } else if (dynamic_cast<std::exception*>(e)) { return new std::exception(*(dynamic_cast<std::exception*>(e))); } } I have coded by taking order reference of below pic. please help me to get classes names in boost:exception which are not in std::exception . if they are in boost::exception only then how to catch that and send to stackToHeapObj and what order i need to follow to add those if checks. try { boost::rethrow_exception(exptr) } here in catch block , we don't know which exception type we have in exptr(ie. std:: or boost:;) then How to catch them. if i use std::exception in catch block then if exptr throws boost::exception type then ... and viceversa..? Please help me to clarify above queries [image: image.png]

3 6

Opinions on merging Assert, StaticAssert, ThrowException into Core
by Nikita Kniazev 17 Oct '21

17 Oct '21

Recently Core grew with additional dependencies on StaticAssert (in 1.76) and ThrowException (in the next release), previously it was only depending on Assert and Config. That made a lot of libraries checkout the same four repositories, three of them containing only a few headers. Merging into a single dependency will affect mostly positive about 100 libraries and negative 1: StlInterfaces (depends on Assert, and will on Core). Please leave a comment at https://github.com/boostorg/core/issues/97 if you think it is a good idea, or have concerns against doing that.

7 14

No more cycles going forward
by Glen Fernandes 16 Oct '21

16 Oct '21

Boost 1.77.0 released with no dependency cycles between libraries. This wasn't easy to achieve and we want to preserve it, going forward. We should not regress and allow libraries to introduce dependency cycles in any future Boost release. i.e. Doing so should be considered a release blocker. Currently, such a regression exists (introduced last month in Context): Asio -> Coroutine -> Context -> Asio It should be fixed before we lock the branches for the 1.78 release, or we should not take this change in the release. Glen

3 3

[Q] Help needed with boost::log, filters and a custom sink backend
by Volker 15 Oct '21

15 Oct '21

Dear Boost experts! I'm new to this list, so please have mercy if I'm not yet familiar with your best practices. Recently, I have been pulling my hair out while trying to use boost::log for a severity-logger-type functionality where the sink backend is not compatible with std::ostream. Best bet was to implement a custom sink backend that does the job in its consume() member. However, I can't get the attribute value for the severity level extracted to an int. For sure, there's something totally obvious I'm missing... Here's the source code (slightly abbreviated): #include <string> #include <boost/log/core.hpp> #include <boost/log/expressions.hpp> #include <boost/log/sinks/basic_sink_backend.hpp> #include <boost/log/sinks/sync_frontend.hpp> #include <boost/log/sources/logger.hpp> #include <boost/log/sources/severity_logger.hpp> #include <boost/log/trivial.hpp> #include <boost/smart_ptr/make_shared_object.hpp> #include <boost/smart_ptr/shared_ptr.hpp> namespace logging = boost::log; namespace sinks = boost::log::sinks; void SomeLogChannel(int severity, const std::string& message) {} class SinkBackend : public sinks::basic_sink_backend<sinks::synchronized_feeding> { public: explicit SinkBackend() {} void consume(logging::record_view const& rec) { std::string message = *rec[boost::log::expressions::smessage]; int severity = 0; if (rec.attribute_values().count("Severity")) { // severity = rec.attribute_values()["Severity"].extract<int>(); // cannot convert from 'boost::log::v2s_mt_nt6::value_ref<T,TagT>' to 'int' with T=int, TagT=void } SomeLogChannel(severity, message); } }; void init_logging() { typedef sinks::synchronous_sink<SinkBackend> sink_t; boost::shared_ptr<logging::core> core = logging::core::get(); boost::shared_ptr<SinkBackend> backend(new SinkBackend()); boost::shared_ptr<sink_t> sink(new sink_t(backend)); core->add_sink(sink); core->set_filter(logging::trivial::severity >= logging::trivial::error); } int main(int, char* []) { init_logging(); boost::log::sources::severity_logger< logging::trivial::severity_level > lg; BOOST_LOG_SEV(lg, logging::trivial::trace) << "Trace message"; BOOST_LOG_SEV(lg, logging::trivial::error) << "Error message"; return 0; } If this is a clumsy approach and there's a more elegant solution to feed log messages into SomeLogChannel() (in reality, it's a bit more complex because it involves a class, a couple interfaces, etc.), don't hesitate to comment as well. I'm still trying to wrap my mind around the topic. Thanks a bunch in advance and greets, Volker -- @: boost(a)bartheld.net

1 0

regarding spurious wakeup in boost 1.76
by Daggumati, Rajesh 13 Oct '21

13 Oct '21

HI Team, I have been facing an issue regarding conditionvariable.timed_wait() This function is returning false everywhere in my code(windows platform). It not waiting for notify signal. conditionvariable.timed_wait(lock1,boost::posix_time::milliseconds(100)) I have found same issue information in google. [Thread] thousands of spurious wakeups from timed_wait() per second (narkive.com)<https://boost-users.boost.narkive.com/xu7advkY/thread-thousands-of-spurious…> did this issue get fixed in boost 1.76.0? Please help me how to fix this issue. Regards, Rajesh D Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.

1 2

Evolving Boost.ContainerHash
by Peter Dimov 13 Oct '21

13 Oct '21

I've been thinking of updating and evolving Boost.ContainerHash, so I e-mailed Daniel James to see what his thoughts on that are. He says he's not going to come back to it, since he's moved on from C++. (Why would anyone do so is beyond me. :-)) More specifically, what I'm envisaging is updating boost::hash to take a seed: template<class T> struct hash { hash(); // as before explicit hash( size_t seed ); size_t operator()(T const& v) { return detail::hash_combine(seed, hash_value(v)); } }; The public hash_combine then becomes: template<class T> void hash_combine( size_t& seed, T const& v ) { return hash<T>(seed)(v); } This allows passing seeded hashes to unordered containers, without any changes to the latter: std::unordered_map<std::string, int, boost::hash<std::string>> map( 0, boost::hash<std::string>( 0x12345678 ) ); Seeding user-exposed hash tables is a good security practice which prevents (or makes less likely) some DoS attacks. The combiner function, detail::hash_combine, will also need to be updated to something that is state of the art for 2021, rather than for 2004. (ContainerHash is already using a more modern implementation of hash_combine, but not in all cases.) The implementation can be cleaned up by removing the C++98 era workarounds for compilers not supporting partial specialization, function template ordering, or argument-dependent lookup. The documentation is also due to a refresh, as the mentions of TR1 are no longer relevant. I also think that Boost.ContainerHash should just be renamed to Boost.Hash as that's what it is - it defines boost::hash. So, I am thinking of taking over ContainerHash and doing all that, if there are no objections.

2 3

[CMake] Can/should we specify optional dependencies
by John Maddock 11 Oct '21

11 Oct '21

I have a regex bug report relating to linking to ICU when using CMake: https://github.com/boostorg/regex/issues/143 Is there a correct way to specify in the CMake file that if you use header X, then you should also link to library Y, but otherwise not? Thanks, John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

5 9

Boost::posixtime issue
by mahesh pramod 07 Oct '21

07 Oct '21

Hi , I am getting false always for this timed_wait function . does posix_time supports in windows as its not looking for notify signal. scoped_lock_t lock(m_mutex); EXPECT_TRUE(m_condition_variable.timed_wait(lock, boost::posix_time::milliseconds(500))) << "Should get signalled (true) not time out";

1 0

boost::posix_time issue
by mahesh pramod 06 Oct '21

06 Oct '21

Hi , I am getting false always for this timed_wait function . does posix_time supports in windows as its not looking for notify signal. scoped_lock_t lock(m_mutex); EXPECT_TRUE(m_condition_variable.timed_wait(lock, boost::posix_time::milliseconds(500))) << "Should get signalled (true) not time out";

1 0

MSYS2 - MinGW64 - Windows 10 Pro - GCC 10.2.0 - undefined references
by Jens Kallup 05 Oct '21

05 Oct '21

Hello Community, I running Windows 10 Pro. MSYS2 - MinGW64-bit with gcc/g++ 10.2.0. I have download the 1_77 Version of Boost, compile it with b2 in the msys2 shell terminal. I could not replace cxx11 to cxx17. All options to build.bat, and b2.exe/sh to switch to cxx17 have not be worked. I downwrite the simple "Boost.program_options" example. I could compile it without any errors or warnings. But I ran into trouble at link stage. I have tried libs for x32/64, single/multi thread, debug/release, static/dynamic. All ends up with the same error of undefined reference explained below. Here comes the known source code to the problem: ---%<--- # include <boost/program_options.hpp> # include "common.h" namespace po = boost::program_options; int main(int argc, char *argv[]) { try { po::options_description desc("Allowed Options"); desc.add_options() ("help", "shows the help page") ("compression", po::value<int>(), "set compression level") ; po::variables_map vm; po::store(po::parse_command_line(argc, argv, desc), vm); po::notify(vm); if (vm.count("help")) { std::cout << desc << std::endl; return SUCCESS; } if (vm.count("compression")) { std::cout << "Compression level was set to " << vm["compression"].as<int>() << "." << std::endl; } else { std::cout << "Compression level was not set." << std::endl; } } catch(...) { std::cerr << "caugth a error.\n"; return FAILURE; } return SUCCESS; } --->%--- Here is a list of the files that are generated during the build time: devlab1@rk1700 MINGW64 /e/Projekte/news $ dir ../boost_1_77_0/stage/lib/ cmake libboost_atomic-mgw10-mt-d-x32-1_77.a libboost_atomic-mgw10-mt-d-x64-1_77.a libboost_atomic-mgw10-mt-s-x64-1_77.a libboost_atomic-mgw10-mt-x32-1_77.a libboost_atomic-mgw10-mt-x64-1_77.a libboost_chrono-mgw10-mt-d-x32-1_77.a libboost_chrono-mgw10-mt-d-x64-1_77.a libboost_chrono-mgw10-mt-s-x64-1_77.a libboost_chrono-mgw10-mt-x32-1_77.a libboost_chrono-mgw10-mt-x64-1_77.a libboost_container-mgw10-mt-d-x32-1_77.a libboost_container-mgw10-mt-d-x64-1_77.a libboost_container-mgw10-mt-s-x64-1_77.a libboost_container-mgw10-mt-x32-1_77.a libboost_container-mgw10-mt-x64-1_77.a libboost_context-mgw10-mt-d-x32-1_77.a libboost_context-mgw10-mt-d-x64-1_77.a libboost_context-mgw10-mt-s-x64-1_77.a libboost_context-mgw10-mt-x32-1_77.a libboost_context-mgw10-mt-x64-1_77.a libboost_contract-mgw10-mt-d-x32-1_77.a libboost_contract-mgw10-mt-d-x64-1_77.a libboost_contract-mgw10-mt-s-x64-1_77.a libboost_contract-mgw10-mt-x32-1_77.a libboost_contract-mgw10-mt-x64-1_77.a libboost_coroutine-mgw10-mt-d-x32-1_77.a libboost_coroutine-mgw10-mt-d-x64-1_77.a libboost_coroutine-mgw10-mt-s-x64-1_77.a libboost_coroutine-mgw10-mt-x32-1_77.a libboost_coroutine-mgw10-mt-x64-1_77.a libboost_date_time-mgw10-mt-d-x32-1_77.a libboost_date_time-mgw10-mt-d-x64-1_77.a libboost_date_time-mgw10-mt-s-x64-1_77.a libboost_date_time-mgw10-mt-x32-1_77.a libboost_date_time-mgw10-mt-x64-1_77.a libboost_exception-mgw10-mt-d-x32-1_77.a libboost_exception-mgw10-mt-d-x64-1_77.a libboost_exception-mgw10-mt-s-x64-1_77.a libboost_exception-mgw10-mt-x32-1_77.a libboost_exception-mgw10-mt-x64-1_77.a libboost_fiber-mgw10-mt-d-x64-1_77.a libboost_fiber-mgw10-mt-s-x64-1_77.a libboost_fiber-mgw10-mt-x64-1_77.a libboost_filesystem-mgw10-mt-d-x32-1_77.a libboost_filesystem-mgw10-mt-d-x64-1_77.a libboost_filesystem-mgw10-mt-s-x64-1_77.a libboost_filesystem-mgw10-mt-x32-1_77.a libboost_filesystem-mgw10-mt-x64-1_77.a libboost_graph-mgw10-mt-d-x32-1_77.a libboost_graph-mgw10-mt-d-x64-1_77.a libboost_graph-mgw10-mt-s-x64-1_77.a libboost_graph-mgw10-mt-x32-1_77.a libboost_graph-mgw10-mt-x64-1_77.a libboost_iostreams-mgw10-mt-d-x32-1_77.a libboost_iostreams-mgw10-mt-d-x64-1_77.a libboost_iostreams-mgw10-mt-s-x64-1_77.a libboost_iostreams-mgw10-mt-x32-1_77.a libboost_iostreams-mgw10-mt-x64-1_77.a libboost_json-mgw10-mt-d-x32-1_77.a libboost_json-mgw10-mt-d-x64-1_77.a libboost_json-mgw10-mt-s-x64-1_77.a libboost_json-mgw10-mt-x32-1_77.a libboost_json-mgw10-mt-x64-1_77.a libboost_locale-mgw10-mt-d-x32-1_77.a libboost_locale-mgw10-mt-d-x64-1_77.a libboost_locale-mgw10-mt-s-x64-1_77.a libboost_locale-mgw10-mt-x32-1_77.a libboost_locale-mgw10-mt-x64-1_77.a libboost_log-mgw10-mt-d-x32-1_77.a libboost_log-mgw10-mt-d-x64-1_77.a libboost_log-mgw10-mt-s-x64-1_77.a libboost_log-mgw10-mt-x32-1_77.a libboost_log-mgw10-mt-x64-1_77.a libboost_log_setup-mgw10-mt-d-x32-1_77.a libboost_log_setup-mgw10-mt-d-x64-1_77.a libboost_log_setup-mgw10-mt-s-x64-1_77.a libboost_log_setup-mgw10-mt-x32-1_77.a libboost_log_setup-mgw10-mt-x64-1_77.a libboost_math_c99-mgw10-mt-d-x64-1_77.a libboost_math_c99-mgw10-mt-s-x64-1_77.a libboost_math_c99-mgw10-mt-x64-1_77.a libboost_math_c99f-mgw10-mt-d-x64-1_77.a libboost_math_c99f-mgw10-mt-s-x64-1_77.a libboost_math_c99f-mgw10-mt-x64-1_77.a libboost_math_c99l-mgw10-mt-d-x64-1_77.a libboost_math_c99l-mgw10-mt-s-x64-1_77.a libboost_math_c99l-mgw10-mt-x64-1_77.a libboost_math_tr1-mgw10-mt-d-x64-1_77.a libboost_math_tr1-mgw10-mt-s-x64-1_77.a libboost_math_tr1-mgw10-mt-x64-1_77.a libboost_math_tr1f-mgw10-mt-d-x64-1_77.a libboost_math_tr1f-mgw10-mt-s-x64-1_77.a libboost_math_tr1f-mgw10-mt-x64-1_77.a libboost_math_tr1l-mgw10-mt-d-x64-1_77.a libboost_math_tr1l-mgw10-mt-s-x64-1_77.a libboost_math_tr1l-mgw10-mt-x64-1_77.a libboost_nowide-mgw10-mt-d-x32-1_77.a libboost_nowide-mgw10-mt-d-x64-1_77.a libboost_nowide-mgw10-mt-s-x64-1_77.a libboost_nowide-mgw10-mt-x32-1_77.a libboost_nowide-mgw10-mt-x64-1_77.a libboost_prg_exec_monitor-mgw10-mt-d-x32-1_77.a libboost_prg_exec_monitor-mgw10-mt-d-x64-1_77.a libboost_prg_exec_monitor-mgw10-mt-s-x64-1_77.a libboost_prg_exec_monitor-mgw10-mt-x32-1_77.a libboost_prg_exec_monitor-mgw10-mt-x64-1_77.a libboost_program_options-mgw10-mt-d-x32-1_77.a libboost_program_options-mgw10-mt-d-x64-1_77.a libboost_program_options-mgw10-mt-s-x64-1_77.a libboost_program_options-mgw10-mt-x32-1_77.a libboost_program_options-mgw10-mt-x64-1_77.a libboost_python39-mgw10-mt-d-x32-1_77.a libboost_python39-mgw10-mt-d-x64-1_77.a libboost_python39-mgw10-mt-x32-1_77.a libboost_python39-mgw10-mt-x64-1_77.a libboost_random-mgw10-mt-d-x32-1_77.a libboost_random-mgw10-mt-d-x64-1_77.a libboost_random-mgw10-mt-s-x64-1_77.a libboost_random-mgw10-mt-x32-1_77.a libboost_random-mgw10-mt-x64-1_77.a libboost_regex-mgw10-mt-d-x32-1_77.a libboost_regex-mgw10-mt-d-x64-1_77.a libboost_regex-mgw10-mt-s-x64-1_77.a libboost_regex-mgw10-mt-x32-1_77.a libboost_regex-mgw10-mt-x64-1_77.a libboost_serialization-mgw10-mt-d-x32-1_77.a libboost_serialization-mgw10-mt-d-x64-1_77.a libboost_serialization-mgw10-mt-s-x64-1_77.a libboost_serialization-mgw10-mt-x32-1_77.a libboost_serialization-mgw10-mt-x64-1_77.a libboost_stacktrace_basic-mgw10-mt-d-x32-1_77.a libboost_stacktrace_basic-mgw10-mt-x32-1_77.a libboost_stacktrace_noop-mgw10-mt-d-x32-1_77.a libboost_stacktrace_noop-mgw10-mt-d-x64-1_77.a libboost_stacktrace_noop-mgw10-mt-s-x64-1_77.a libboost_stacktrace_noop-mgw10-mt-x32-1_77.a libboost_stacktrace_noop-mgw10-mt-x64-1_77.a libboost_stacktrace_windbg-mgw10-mt-d-x64-1_77.a libboost_stacktrace_windbg-mgw10-mt-s-x64-1_77.a libboost_stacktrace_windbg-mgw10-mt-x64-1_77.a libboost_stacktrace_windbg_cached-mgw10-mt-d-x64-1_77.a libboost_stacktrace_windbg_cached-mgw10-mt-s-x64-1_77.a libboost_stacktrace_windbg_cached-mgw10-mt-x64-1_77.a libboost_system-mgw10-mt-d-x32-1_77.a libboost_system-mgw10-mt-d-x64-1_77.a libboost_system-mgw10-mt-s-x64-1_77.a libboost_system-mgw10-mt-x32-1_77.a libboost_system-mgw10-mt-x64-1_77.a libboost_test_exec_monitor-mgw10-mt-d-x32-1_77.a libboost_test_exec_monitor-mgw10-mt-d-x64-1_77.a libboost_test_exec_monitor-mgw10-mt-s-x64-1_77.a libboost_test_exec_monitor-mgw10-mt-x32-1_77.a libboost_test_exec_monitor-mgw10-mt-x64-1_77.a libboost_thread-mgw10-mt-d-x32-1_77.a libboost_thread-mgw10-mt-d-x64-1_77.a libboost_thread-mgw10-mt-s-x64-1_77.a libboost_thread-mgw10-mt-x32-1_77.a libboost_thread-mgw10-mt-x64-1_77.a libboost_timer-mgw10-mt-d-x32-1_77.a libboost_timer-mgw10-mt-d-x64-1_77.a libboost_timer-mgw10-mt-s-x64-1_77.a libboost_timer-mgw10-mt-x32-1_77.a libboost_timer-mgw10-mt-x64-1_77.a libboost_type_erasure-mgw10-mt-d-x32-1_77.a libboost_type_erasure-mgw10-mt-d-x64-1_77.a libboost_type_erasure-mgw10-mt-s-x64-1_77.a libboost_type_erasure-mgw10-mt-x32-1_77.a libboost_type_erasure-mgw10-mt-x64-1_77.a libboost_unit_test_framework-mgw10-mt-d-x32-1_77.a libboost_unit_test_framework-mgw10-mt-d-x64-1_77.a libboost_unit_test_framework-mgw10-mt-s-x64-1_77.a libboost_unit_test_framework-mgw10-mt-x32-1_77.a libboost_unit_test_framework-mgw10-mt-x64-1_77.a libboost_wave-mgw10-mt-d-x32-1_77.a libboost_wave-mgw10-mt-d-x64-1_77.a libboost_wave-mgw10-mt-s-x64-1_77.a libboost_wave-mgw10-mt-x32-1_77.a libboost_wave-mgw10-mt-x64-1_77.a libboost_wserialization-mgw10-mt-d-x32-1_77.a libboost_wserialization-mgw10-mt-d-x64-1_77.a libboost_wserialization-mgw10-mt-s-x64-1_77.a libboost_wserialization-mgw10-mt-x32-1_77.a libboost_wserialization-mgw10-mt-x64-1_77.a Here comes the command line for compile/link the application $ /mingw64/bin/x86_64-w64-mingw32-g++ -o winperm.exe ./tmp/main.o ./tmp/network.o ./tmp/threading.o ./tmp/translator.o ./tmp/tv_tui.o ./tmp/permutation.o -fopenmp -MD -I/E/Projekte/boost_1_77_0/stage/lib -L../boost_1_77_0/stage/lib -L../tvision/build -L/mingw64/lib -L/mingw64/x86_64-w64-mingw32/lib -ltvision -lkernel32 -luser32 -lwinmm -lws2_32 -lintl -lpthread -lboost_iostreams-mgw10-mt-x64-1_77 -lboost_program_options-mgw10-mt-x64-1_77 And here comes the error output from the linker LD: E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options25basic_command_line_parserIcE12extra_parserENS_9 function1ISt4pairISsSsERKSsEE[_ZN5boost15program_options25basic_command_line_parserIcE12 extra_parserENS_9function1ISt4pairISsSsERKSsEE]+0x41): undefined reference to `boost::program_options::detail::cmdline::set_additional_parser(boost::function1 <std::pair<std::string, std::string>, std::string const&>)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options11to_internalISsEESt6vectorISsSaISsEERKS2_IT_Sa IS5_EE[_ZN5boost15program_options11to_internalISsEESt6vectorISsSaISsEERKS2_IT_Sa IS5_EE]+0x48): undefined reference to `boost::program_options::to_internal (std::string const&)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64- mingw32/bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options25basic_command_line_parserIcEC1EiPKPKc [_ZN5boost15program_options25basic_command_line_parserIcEC1EiPKPKc]+0xaf): undefined reference to `boost::program_options::detail::cmdline::cmdline(std::vector<std::string, std::allocator<std::string> > const&)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc:(.text.startup.main+0xb8): undefined reference to `boost::program_options::options_description::options_description(std::string const&, unsigned int, unsigned int)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc:(.text.startup.main+0x281): undefined reference to `boost::program_options::abstract_variables_map::operator[](std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options10validators17get_single_stringIcEERKSbIT_St11 char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb[_ZN5boost15program_options10validators17 get_single_stringIcEERKSbIT_St11char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb]+0xa1): undefined reference to `boost::program_options::validation_error::get_template(boost::program_options:: validation_error::kind_t)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options10validators17get_single_stringIcEERKSbIT_St11 char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb[_ZN5boost15program_options10validators17 get_single_stringIcEERKSbIT_St11char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb]+0xba): undefined reference to `boost::program_options::error_with_option_name::error_with_option_name(std::string const&, std::string const&, std::string const&, int)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options10validators17get_single_stringIcEERKSbIT_St11 char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb[_ZN5boost15program_options10 validators17get_single_stringIcEERKSbIT_St11char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS 7_EEb]+0x199): undefined reference to `boost::program_options::validation_error::get_template(boost::program_options:: validation_error::kind_t)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options10validators17get_single_stringIcEERKSbIT_St11 char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb[_ZN5boost15program_options10validators17 get_single_stringIcEERKSbIT_St11char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb]+0x1b2): undefined reference to `boost::program_options::error_with_option_name::error_with_option_name(std::string const&, std::string const&, std::string const&, int)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options8validateIicEEvRNS_3anyERKSt6vectorISbIT0_St11 char_traitsIS5_ESaIS5_EESaIS9_EEPT_l[_ZN5boost15program_options8validateIicEEvRNS_3any ERKSt6vectorISbIT0_St11char_traitsIS5_ESaIS5_EESaIS9_EEPT_l]+0x5db): undefined reference to `boost::program_options::invalid_option_value::invalid_option_value(std::string const&)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost10wrapexceptINS_15program_options20invalid_option_valueEEE[_ZTVN5 boost10wrapexceptINS_15program_options20invalid_option_valueEEE]+0x60): undefined reference to `boost::program_options::error_with_option_name::substitute_placeholders(std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost10wrapexceptINS_15program_options16validation_errorEEE[_ZTVN5boost10 wrapexceptINS_15program_options16validation_errorEEE]+0x60): undefined reference to `boost::program_options::error_with_option_name::substitute_placeholders(std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost15program_options16validation_errorE[_ZTVN5boost15program_options16 validation_errorE]+0x30): undefined reference to `boost::program_options::error_with_option_name::substitute_placeholders(std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost15program_options20invalid_option_valueE[_ZTVN5boost15 program_options20invalid_option_valueE]+0x30): undefined reference to `boost::program_options::error_with_option_name::substitute_placeholders(std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost15program_options11typed_valueIicEE[_ZTVN5boost15 program_options11typed_valueIicEE]+0x38): undefined reference to `boost::program_options::value_semantic_codecvt_helper<char>::parse(boost::any&, std::vector<std::string, std::allocator<std::string> > const&, bool) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$.refptr._ZN5boost15program_options3argE[.refptr._ZN5boost15program_options3 argE]+0x0): undefined reference to `boost::program_options::arg' collect2.exe: error: ld returned 1 exit status Did I miss something ? The question is now, how can I use boost under msys2 with mingw64 ? Thanks for helping hands, paule32

1 0

cybersecuriy for boost
by rajesh daggumati 04 Oct '21

04 Oct '21

HI, Is there any group who supports on cyber security while we are using boost 1.76.0

4 3

queries regarding usage of boost 1.76.0 .
by mahesh pramod 04 Oct '21

04 Oct '21

Hi, I have below queries regarding boost 1.76.0. I have been faced these below queries. 1.how to check boost is statically binded or dynamically binded with my code? is this binding related to virtual concept? 2.how boost interacts with any software? 3. does boost takes our data for any use? ex: when we use sql servers they take our data for testing purpose. Like that does boost take?

2 1

Re: [boost] Simple boost fix for sparc64
by John Klos 30 Sep '21

30 Sep '21

>> Here's a failure example: >> https://ftp.ziaspace.com/pub/pkgsrc/reports/9.0_2021Q2/sparc64/boost-libs-1… > > Seems like it's already fixed: > https://github.com/boostorg/predef/commit/1be0e4a2d8db15a405f64a6f65507b87c… Excellent. I'll look for that in 1.78.0. Thanks, John Klos

1 0

regarding exception_ptr
by rajesh daggumati 30 Sep '21

30 Sep '21

Hi Team, PFB code snippet: try { BOOST_THROW_EXCEPTION(std::invalid_argument("Blah")); } catch(...) { boost::exception_ptr exception = boost::current_exception(); const std::invalid_arguement* p; try{ boost :: rethrow_exception(exceptionptr) } catch(std::invalid_argument &e) { p = dynamic_cast<const std::invalid_argument*>(&e) } const std::invalid_argument* actualStdPtr = ExceptionHelper::ExtractConstPtr<std::invalid_argument>(exceptionptr); EXPECT_TRUE(((void*)p) == ((void*)actualStdPtr)) << "Same Object"; //this condition is getting failed. }} static const t* ExtractConstPtr(boost::exception_ptr ep) { try { boost::rethrow_excepton(ep); } catch(T &e){ const T* exceptType = dynamic_cast<const T*>(&e); return exceptType; } catch (std::exception & e){ const T* exceptType = dynamic_cast<const T*>(&e); return exceptType; } } //EXPECT_TRUE(((void*)p) == ((void*)actualStdPtr)) -->what will be the reason to get failed as I do same thing in both cases. Regards, Rajesh D

2 2

conversion issues from boost::exception_ptr to exception class shared_ptr
by rajesh daggumati 29 Sep '21

29 Sep '21

HI Team, // i have caught exception in exception_ptr and I and trying to convert to ExceptionPtr_t but I am facing issue at below derived->severity(). * unknown file: error: SEH exception with code 0xc0000005 thrown in the test body.* *code snippet is :* *E*xceptionPtr_t ExceptionHelper::TryGetExceptionPtr(boost::exception_ptr exception) { ExceptionPtr_t result ; std::string res; if(!exception) return result; try { boost::rethrow_exception(exception) *}catch(boost::exception &e)* *{boost::throw_file::value_type const* throw_file_data = boost::get_error_info<boost::throw_file>(e);* *if(* *throw_file_data)* *{* * result = exceptionPtr_t(new ExceptionWrapper(exception,*throw_filed_data,true))* *}* *return result;* *}* class Exception : public virtual std::exception, public virtual boost::exception { protected: string what; serviorytype m_severity; public: explicit Exception(const std::string& what); virtual ~Exception() throw() {} // we have some member functions like severity(),setseverity(value)... } class ExceptionWrapper : public Exception { private: string m_what_inner; boost::exception_ptr m_inner; public: explict ExceptionWrapper(boost::exception_ptr inner,string &what() = std::string,bool copythrow = true); explict ExceptionWrapper(boost::exceptionPtr_t inner,string &what() = std::string,bool copythrow = true); virtual ~ExceptionWrapper() throw(){} // some methods like severity(),setSeverity(value),.....) } I was doing like: const Exception* derived = reinterPret_cast<const Exception*> (&exception)// here exception is type of exception_ptr if(derived) { derived->severity(); // here exception is coming... if i put this line in try block then its going for catch block and new exception is being rasied. if i dont put try block then *unknown file: error: SEH exception with code 0xc0000005 thrown in the test body.* } Please help me to resolve this issue

2 1

Simple boost fix for sparc64
by John Klos 27 Sep '21

27 Sep '21

Hello, boost people, This is a small, simple patch to make boost compile properly on NetBSD/sparc64, at very least, and on SPARC and UltraSPARC in general. Here's a failure example: https://ftp.ziaspace.com/pub/pkgsrc/reports/9.0_2021Q2/sparc64/boost-libs-1… Thanks very much, John Klos --- libs/predef/include/boost/predef/architecture/sparc.h.orig 2021-09-27 16:03:19.965761565 +0000 +++ libs/predef/include/boost/predef/architecture/sparc.h 2021-09-27 16:11:18.084758689 +0000 @@ -34,10 +34,10 @@ #if defined(__sparc__) || defined(__sparc) # undef BOOST_ARCH_SPARC -# if !defined(BOOST_ARCH_SPARC) && (defined(__sparcv9) || defined(__sparc_v9__) +# if !defined(BOOST_ARCH_SPARC) && (defined(__sparcv9) || defined(__sparc_v9__)) # define BOOST_ARCH_SPARC BOOST_VERSION_NUMBER(9,0,0) # endif -# if !defined(BOOST_ARCH_SPARC) && (defined(__sparcv8) || defined(__sparc_v8__) +# if !defined(BOOST_ARCH_SPARC) && (defined(__sparcv8) || defined(__sparc_v8__)) # define BOOST_ARCH_SPARC BOOST_VERSION_NUMBER(8,0,0) # endif # if !defined(BOOST_ARCH_SPARC)

2 1

access violation and data stealing
by rajesh daggumati 27 Sep '21

27 Sep '21

Hi Team, I am preparing a document for boost library(1.76.0) to be used in our organisation. as part of documnet, I need some information. 1.Regarding data integrity and security of gtest and how it interacts with any software. 2.if we use boost, we see any access violation or data stealing? 3.is there any group who supports on cyber security while we are using boost 1.76.0 Please kindly answer above 3 queries. Regards, Raesh D

2 1

please guide me to open source world
by Saurabh Tiwari 23 Sep '21

23 Sep '21

Hai SIR/MAAM this side SAURABH TIWARI currently I am in my 3rd year of Btech I don’t know much about the open source can you please help how to get started for the same I know C++, C, basic data structures and algorithms I would be very thankful if you please help me sir so that I can contribute to this open-source world.

4 5

New to boost
by rajesh daggumati 22 Sep '21

22 Sep '21

Hi Team, in my code,I had to write like below: const int* p = boost::get_error_info<boost::throw_line>(exception); But while building the code,I am facing issue like below: error C2683: 'dynamic_cast':'boost::exception_ptr' is not a polymorphic type.. Then I have added one dummy virtual function in exception_ptr class then this issue got resolved but I am getting some test cases failed at this line: Const int* p = boost::get_error_info<boost::throw_line>(exception); Please help me where will be the issue is.what will be the solution.

4 3

Published various template libraries...
by David Bien 22 Sep '21

22 Sep '21

That I have been working on over the past 23 years (when not working for actual money). Directed Graph Template Library: https://github.com/davidbien/dgraph Original email to boost mailing list from year 2000: https://lists.boost.org/Archives/boost/2000/04/2834.php Lexical Analyzer Generator Template Library: https://github.com/davidbien/lexang Original email to boost mailing list from year 2000: https://lists.boost.org/Archives/boost/2000/04/2837.php This depends on the dgraph git submodule above. The above are written in "old" C++ - but updated to compiler in the latest compilers (MSVC, clang11). Built on the above: XML Parser/Writer/DOM Template Library: https://github.com/davidbien/xmlpinc This I developed over the last winter. It is written in C++20 and requires msvc19 or clang11. I heavily use C++20 concepts. There is a lack of documentation. As well: XML Parser/Writer/DOM Development Environment: https://github.com/davidbien/xmlp This contains the LEX specifications (which are written using overridden C++ operators in a namespace) that produce the state machines for UTF8, UTF16 and UTF32 versions of the XML parser - which are then, upon modification, checked into: https://github.com/davidbien/xmlpinc This as well requires the nearly latest versions of MSVC or clang. Once again: There is a lack of documentation. I don't use boost in these libraries - preferring not to have a dependency on it. I also published: https://github.com/davidbien/bienutil Which contains a lot of stuff from year 2000, but also contains some new stuff which is pretty cool: 1. An actually performant and memory-conservative implementation of a Van Emde Boas Tree: https://github.com/davidbien/bienutil/blob/master/_vebtree.h 2. An "exponential chunked array" (misnamed as "logarray.h") that uses a single piece of memory initially: https://github.com/davidbien/bienutil/blob/master/_logarray.h 3. A bunch of other stuff that I wrote back in 2000 since there wasn't much available back then in terms of C++ utility templates. There is a testbed for the dgraph impl but I haven't yet converted them to CMAKE/googletest. There is also a testbed for the vebtree impl but once again not converted to CMAKE/googletest. (I only have so many fingers). Anyway, I'd like to know what people think. The XML parser is meant to be fully compliant with XML Version 1.0 and meant to be a development environment that can be used to extend to full compatibility. I am currently working on a Parser Generator Template Library (think replacement for yacc or bison) that will work with my LEX replacement and allow use of the LEX terminals in the EBNF for the parser specification (which will again be encoding using C++ overridden operators in a namespace). Sincerely, David Bien

2 2

Please guide me for open source
by Saurabh Tiwari 21 Sep '21

21 Sep '21

Hai SIR/MAAM this side SAURABH TIWARI currently I am in my 3rd year of Btech I don’t know much about open source can you please help how to get started for the same I know C++ ,C, basic data structures and algorithms, html , css (basics), and learning web development. I would be very thankful of you please help me sir so that I can contribute to this open source world.

1 0

[any] [basic_any] This seems like a little pearl in Boost 1.77, but it's a bit underdocumented?
by Viktor Sehr 21 Sep '21

21 Sep '21

I just discovered basic_any which is a very nice addition for me. However it's a bit under-documented for the moment. For example: - I assume it's stack-allocated, does it allocate on the heap if assigned an object larger than the stack (like small_vector) or is this not allowed (like static_vector)? - An idea would also be to add a flag which breaks compilation if an object larger than the OptimizeForSize argument is assigned? - (For detail) If allocated on the stack, are the first bytes of the basic_any the same as the contained object? /Viktor

2 2

[ICL] Proposal to support other set/map implementations
by Martin Duvanel 18 Sep '21

18 Sep '21

Hello, We are using boost::icl::interval_set with very large amounts of intervals, and we are having some performance issues. Profiling showed that, in our use-case, a lot of time was spent on memory allocation/deallocation, and swapping std::set for boost::flat_set made a huge, positive difference. We may have a very specific use-case, but would you consider a small modification to the library inside "boost/icl/impl_config.hpp", in order to open the door for other set/map implementations? Here is the simple change we made to "boost/icl/impl_config.hpp" for this experiment: <code> #if defined(ICL_USE_BOOST_MOVE_IMPLEMENTATION) # define ICL_IMPL_SPACE boost::container #elif defined(ICL_USE_STD_IMPLEMENTATION) # define ICL_IMPL_SPACE std + #elif defined(ICL_USE_CUSTOM_IMPLEMENTATION) + # define ICL_IMPL_SPACE ICL_CUSTOM_IMPL_SPACE #else # define ICL_IMPL_SPACE std #endif </code> And then declaring the following before including: <code> namespace custom_icl { template <class Key, class T, class Compare, class Allocator> using map = boost::container::flat_map<Key, T, Compare, Allocator>; template <class Key, class Compare, class Allocator> using set = boost::container::flat_set<Key, Compare, Allocator>; } // namespace custom_icl #define ICL_USE_CUSTOM_IMPLEMENTATION 1 #define ICL_CUSTOM_IMPL_SPACE custom_icl </code> Would such a change make sense in your opinion? If that's the case, then I would be happy to participate in the contribution. Thank you and best regards, Martin Duvanel

3 4

New contributor in Boost
by RUCHIT RAUSHAN 18 Sep '21

18 Sep '21

Hey there, I am a student of branch Information Technology and currently gaining knowledge in C++. I would love to contribute to the Boost community in every possible way, so I would like to know how to start with it. Thank You! RUCHIT RAUSHAN

3 2

16th Google Summer of Code Participation
by Cem Bassoy 15 Sep '21

15 Sep '21

Since 16 years, the Boost foundation has been selected as a mentor organization by the Google Summer of Code <https://summerofcode.withgoogle.com/> committee. If I am not mistaken, Boost has mentored over 100 students who contributed to existing and experimental boost libraries. This year, 8 students successfully contributed to Boost.Real, Boost.Gil, Boost.Math, Boost.Python, Boost.uBlas, Boost.Multiprecision, see project descriptions <https://summerofcode.withgoogle.com/organizations/6722937052200960/#projects> . Here <https://opensource.googleblog.com/2021/06/google-summer-of-code-2021-studen…> are some stats about GSoC21. I would like to thank all students for their contribution and all mentors who have made this possible. Keep up the good work! All the best, Cem

2 1

New to Boost
by Abhishek Rathore 14 Sep '21

14 Sep '21

Hey! I am a student majoring in Computer Science and am currently learning C++. I would love to contribute to the Boost community in any way possible in the near future so that is why, I would like to know how to go about it. Thanks and Super excited! Abhishek

2 1

Re: [boost] New to Boost
by Kenneth Porter 14 Sep '21

14 Sep '21

--On Tuesday, September 14, 2021 3:41 PM +0530 Abhishek Rathore via Boost <boost(a)lists.boost.org> wrote: > I am a student majoring in Computer Science and am currently learning C++. > I would love to contribute to the Boost community in any way possible in > the near future so that is why, I would like to know how to go about it. Head to Github and check out the issues on all the libraries. Fork, fix, and submit pull requests. <https://svn.boost.org/trac10/wiki/StartModPatchAndPullReq> (I don't see anything here about legal issues. Does one need to file a contributor release?)

1 0

Regarding boost 1.76.0
by rajesh daggumati 09 Sep '21

09 Sep '21

Hi Team, Is boost 1.76.0 version is stable version or not.please confirm me asap. Regards, Rajesh D

4 4

Regarding usage of boost 1.76.0
by rajesh daggumati 08 Sep '21

08 Sep '21

Hi Team, Please help me for below query. What are the steps we need to do to include boost in to our code base and release bour software without any obligation? Ex: include license along with our binaries or we need to publish our code to boost platform....? Are we oblige to share anything to boost? Regards, Rajesh D

2 1

Regarding suppporting end date of boost 1.776.0
by rajesh daggumati 08 Sep '21

08 Sep '21

Hi Team, What is the supporting end date for boost 1.76.0 version? Please let me know asap. Regards, Rajesh D

2 1

Can we create boost-config
by Sreeraj K 06 Sep '21

06 Sep '21

*[I initialially raised this question in https://github.com/boostorg/boost/issues/548 <https://github.com/boostorg/boost/issues/548>, but @mclaw recommended this mailing list.]* Similar to many other packages (eg: curl, krb5, pcre, xml2, xslt etc..), can we also ship boost-config that would provide the installation options ? We can probably start with something like this ? $ /usr/bin/boost-config --help Usage: boost-config [ options ] Options: --cflags print compiler options --ldflags print linker options --prefix print the boost prefix --version print the boost version --help print this usage summary $ /usr/bin/boost-config --version 1.66.0 $ /usr/bin/boost-config --cflags -I/usr/include $ /usr/bin/boost-config --ldflags -L/usr/lib64 -Wl,-R/usr/lib64 Thanks.

4 4

[Asio] Propose optimization patch for QNX OS.
by Alex Steshkin 06 Sep '21

06 Sep '21

Hello, By default on QNX OS the select_reactor class is used, which uses the POSIX select() to wait for I/O and write to a pipe to interrupt the wait. Neither select() nor pipes are efficient on QNX OS. We propose to introduce new ionotify_reactor class for QNX OS, which uses ionotify() and pulses instead of select() and pipes. If you are interested in this patch please let me know how to proceed with it: - what repo and branch should I use for this patch? - what is mandatory test set should be done for this patch? - what documentation should be updated to reflect this patch? Thanks, Alex Steshkin ---------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.

2 1

Fwd: Reg, Boost lib dijkstra_shortest_paths for ECMP paths
by kathireswaran thanuskodi 06 Sep '21

06 Sep '21

Hi Team, I came across the boost lib to identify the shortest paths in an network using vertex/edge properties, and have using dijkstra_shortest_paths method with predecessor_map concept with that able to get the shortest path in the graph. Have a requirement like to know about multiple shortest paths also if present, for example below find the below network diagram with 4 edges, A ------- B | | | | D ------- C Edges -> (A,B), (A,D), (B,C), (C,D) with equal distance 1. With the predecessor_map as of now able to get path as A->B->C so that the parent of C is noted as B. In this example we have ECMP(equal cost multiple path) from src A to destination C, tried to search for existing lib to achieve fetching all the paths but unfortunately unable to identify the way. kindly guide how to get such kind of multiple path info with the existing library itself or not. If there exists how to get those info. *<code snip>* const int num_nodes = 4; enum nodes { A, B, C, D}; Edge edge_array[] = { Edge(A, B), Edge(B, C), Edge(A, D), Edge(C,D) }; int weights[] = { 1, 1, 1,1 }; int num_arcs = sizeof(edge_array) / sizeof(Edge); graph_traits<graph_t>::vertex_iterator i, iend; graph_t g(edge_array, edge_array + num_arcs, weights, num_nodes); property_map<graph_t, edge_weight_t>::type weightmap = get(edge_weight, g); // Manually intialize the vertex index and name maps property_map<graph_t, vertex_index_t>::type indexmap = get(vertex_index, g); property_map<graph_t, vertex_name_t>::type name = get(vertex_name, g); int c = 0; for (boost::tie(i, iend) = vertices(g); i != iend; ++i, ++c) { indexmap[*i] = c; name[*i] = 'A' + c; } vertex_descriptor s = vertex(A, g); property_map<graph_t, vertex_distance_t>::type d = get(vertex_distance, g); property_map<graph_t, vertex_predecessor_t>::type p = get(vertex_predecessor, g); dijkstra_shortest_paths(g, s, predecessor_map(p).distance_map(d)); std::cout << "distances and parents:" << std::endl; graph_traits < graph_t >::vertex_iterator vi, vend; for (boost::tie(vi, vend) = vertices(g); vi != vend; ++vi) { std::cout << "distance(" << name[*vi] << ") = " << d[*vi] << ", "; std::cout << "parent(" << name[*vi] << ") = " << name[p[*vi]] << std:: endl; } std::cout << std::endl; *<code snip>* *<output>* distances and parents: distance(A) = 0, parent(A) = A distance(B) = 1, parent(B) = A*distance(C) = 2, parent(C) = B <<<<<<<<<<<<<<<* distance(D) = 1, parent(D) = A Regards, Kathir

1 0

Documentation is not updating since June 10
by Nikita Kniazev 03 Sep '21

03 Sep '21

https://www.boost.org/doc/libs/develop/doc/html/accumulators.html Last revised: June 10, 2021 at 02:32:49 GMT https://www.boost.org/doc/libs/master/doc/html/accumulators.html Last revised: June 10, 2021 at 15:48:57 GMT I thought it was related to the regression matrix not being updated but that was fixed while documentation is still stale.

1 0

Requesting feedback on boost::algorithm::is_clamped
by Ivan Matek 29 Aug '21

29 Aug '21

Hi everyone, I have made a MR for boost::algorithm::is_clamped. Details are on github <https://github.com/boostorg/algorithm/pull/86>. MR is in draft state since doc changes are missing, but tests and code should™ be correct. If you have no time for review of code I would highly appreciate the feedback on the usability of this function. In my work I needed it a few times within last year, but I would like to get feedback from 5-10 other professional developers from diverse backgrounds.

2 3

Re: [boost] Regression tests not updating
by Nikita Kniazev 27 Aug '21

27 Aug '21

> What do you suggest as a solution? I agree that autodetection with no > way to override it is bad. (In my not yet finished CMake guidelines, I > advocate for only using autodetection to determine the default for > the configuration option, while still allowing the user to override it.) > But how does this translate to something actionable? How would you > have written the Nowide build/Jamfile? Sigh, if I had a good solution I would have presented it. An easiest and no-brainer way to tackle this is to have a per-library variable `is-boost-<library>-required/optional` on which library would have to omit checks (do not import Boost.Config, and do not pass checks that return `<build>no` to project/library requirements): ``` if is-boost-<library>-optional { import ../../config/checks/config : requires ; $(do-not-build-if) = [ requires ... ] ; } lib boost_<library> : ... : $(do-not-build-if) ; ``` However, in my opinion, a library must never add `<build>no` to its requirements by itself. Something external should decide if the build/checks failure is fatal or not: ``` rule can-be-built ( ... ) { import ../../config/checks/config : requires ; return [ requires ... ] ; } boost-install boost_<library> : @can-be-built ; ``` It would be perfect if the library could provide a meaningful explanation why it could not be built/describe not satisfied requirements, but that obviously requires a way more sophisticated system. > This is not a Mailman problem, this is a problem with how you are > replying or your mail client setup. Other users with gmail seem to not > have reply problems so I suspect it is not a gmail specific issue. A > quick look reveals that at least one concern is that your headers lack > the "in reply to". I am subscribed to the daily digest, I cannot reply to a message because I do not receive emails even if someone replied to my message or posted something to a thread I interested to be updated more frequently. > As a side-note: there are non-trivial issues with upgrading to mailman > v3; however, hopefully we will be able to upgrade things in the > not-to-far-off future. Thanks for working on that.

1 0

Regression tests not updating
by Joaquin M López Muñoz 27 Aug '21

27 Aug '21

Hi, just a heads up that regression tests are not updating since Aug 12: https://www.boost.org/development/tests/develop/developer/summary.html https://www.boost.org/development/tests/master/developer/summary.html Thank you, Joaquín M López Muñoz

3 3

Re: [boost] Unconditional conditional building is cursed"
by Nikita Kniazev 27 Aug '21

27 Aug '21

> But the problem has nothing to do with silently not building libraries. It's > caused by libraries assuming that Boost.Config is at ../config. Both have the same root cause -- no way to turn off these build checks. If the checks are not needed there is no need to import Boost.Config and assume its location too. P.S. I do not understand how to reply in the Boost mailing lists, please do not blame me if the message went to the wrong thread, I expressed my frustration about that previously, Boost needs to upgrade its Mailman to v3.

3 2

Unconditional conditional building is cursed
by Nikita Kniazev 26 Aug '21

26 Aug '21

Some libraries (Context, Contract, Fiber, Json, Math, Nowide) are built conditionally and use checks from the Config library to do that (`import ../../config/checks/config : requires ;`). Apparently, it happens to be a PITA for some consumers. Vcpkg had to hack around that and update the hack every Boost release, but Boost 1.76 revealed problems in it ( https://github.com/boostorg/build/issues/724) and Boost 1.77 is blocked by it (https://github.com/microsoft/vcpkg/pull/19556#issuecomment-904702798) I have a mixed feeling about silently not building libraries. I understand that for a lot of people it is reasonable that the default stage build will not build a library on an unsupported compiler. However, it is absolutely bad and a confusing thing to a user that the input is silently ignored when a library is requested using the `--with-<library>` flag. A way to turn off the conditional building of the libraries could also be in debug purposes alongside fixing `--with-<library>` behaviour and making possible for vcpkg to live without resorting to hacking the boost build system. I have no affiliation to vcpkg and I am not a maintainer of any mentioned libraries. It is purely my observation about how Boost is used.

2 1

Does boost have an assert that works nicely with constexpr evaluation, and if not should we add one?
by Ivan Matek 25 Aug '21

25 Aug '21

As you may know assert does not play nicely with constexpr evaluation. But std::is_constant_evaluated/if consteval gives us a way to check when the execution happens. https://www.godbolt.org/z/dfder8h16 Does something like this exist in boost, and if not would that be a nice addition? I can not figure out how to support line numbers, filename in a same way assert does, since assert will obviously just take the line info from where it is called. P.S. smart_assert is just a first name I thought of, I am fine with any name as long as it is not some lengthy monstrosity like is_constant_evaluated

4 7

Need cancel() on async_resolve() to callback the resolve handler immediately
by sandeep m.v 25 Aug '21

25 Aug '21

Hi All, I'm looking for a solution for below problem. We're using async_resolve() to perform DNS resolution using boost::asio::ip::tcp::resolver. In few instances probably during network connectivity issues, async_resolve is taking more time. When our application timeouts in 15seconds while waiting for DNS resolution, cancel() is called on resolver. But, that doesn't callback to resolve handle immediately. When I tried to search for this, it looks like, when a cancel() is called on resolver, that doesn't cancel ongoing actual resolution but may cancel if there are any other pending asynchronous action. It's taking 40seconds at times to call resolve handler even when failed to resolve host and even after calling cancel on it. My application waits until resolve handler is called after cancel() to proceed further processing. Is it possible to stop that async_resolve() and get callback to resolve handle immediately after cancel()? If that's impossible, is there a way that we can stop that doesn't callback resolve handler later? Is it possible to close underlying socket related to async_resolve from my application? Thank you in advance. Regards, Sandeep

4 8

BOOST_IS_CONSTANT_EVALUATED_INT(integer-expression)(integer-expression)
by Robert Ramey 24 Aug '21

24 Aug '21

A couple of questions regarding the above new boost config macro. a) I note that this "breaks the pattern" of BOOST_NO_... which I was expecting. I've got no complaint about this, just like being consistent when possible. b) My intended usage is something like: template<typename T> constexpr interval<T> get_interval(const & T t){ return BOOST_IS_CONSTANT_EVALUATED_INT(t) ? interval<T>(t, t) : interval<T>( std::numeric_limits<T>::min(), std::numeric_limits<T>::max() ); } is this the intended way to use this? If not, what would be the correct usage. c) In my Jamfiles I generally have a few tests which run conditionally on the config macro values like this: test-bsl-run_files test_array : A : : requires cxx11_hdr_array ; #BOOST_NO_CXX11_HDR_ARRAY What should I use with the above macro? Particularly confusing is the usage of _NO_ in the macro and the exclusion of _no_ in the requires variable. Should it be something like this. test test_is_constant_evaluted : A : : requires cxx20_no_is_constant_evaluated_int ; #BOOST_IS_CONSTANT_EVALUATED_INT d) Looks like part of this already checked into config.hpp on the develop branch. I would like to add something to my current develop to permit me to start using this now until you get the final code checked in. Any suggestions about the easiest way to do this? I'm ok with inserting some code temporarily but would prefer not to have to sprinkle it all over the place. Robert Ramey

3 8

Strange b2 headers problem
by Edward Diener 24 Aug '21

24 Aug '21

I switched my main boost repository from the 'develop' branch to an earlier tagged boost release to try something out in that earlier release. Everything went fine with switching the main repository and all submodules. I wiped out all the header links from the boost subdirectory and I tried b2 headers, only to get: error: Cannot create link boost\property_map\parallel\basic_reduce.hpp to libs\property_map_parallel\include\boost\property_map\parallel\basic_reduce.hpp. error: Link previously defined to another file, libs\property_map\include\boost\property_map\parallel\basic_reduce.hpp. This makes no sense since there is a completely empty boost subdirectory under my main boost repository directory. How do I fix this problem ?

2 3

[release]Boost 1.77.0
by Marshall Clow 22 Aug '21

22 Aug '21

Release 1.77.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains two new libraries and numerous enhancements and bug fixes for existing libraries. * Describe: A C++14 reflection library, from Peter Dimov. Provides macros for describing enumerators and struct/class members, and primitives for querying this information. * Lambda2: A C++14, dependency-free, single header lambda library, from Peter Dimov. For details, including download links, see <http://www.boost.org/users/news/version_1.77.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.77.0/> To install this release on your system, see <http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. Thanks, -- The Boost Release Team Marshall Clow, Michael Caisse, Glen Fernandes

4 7

Discuss: Editorial Control Over Repositories and Libraries
by Vinnie Falco 21 Aug '21

21 Aug '21

So, I have a whole bunch of new libraries marching towards completion and proposal for Boost. I have Boost.URL and Boost.HTTP-Proto in the works, and there is some code that I want to share between the two. Files like these: Algorithms to assist processing RFC7230 compliant input: <https://github.com/vinniefalco/http_proto/blob/9d3144c60b3426509b45cc63dbb3…> <https://github.com/vinniefalco/http_proto/blob/9d3144c60b3426509b45cc63dbb3…> <https://github.com/vinniefalco/http_proto/blob/9d3144c60b3426509b45cc63dbb3…> These are public interfaces, and they are equally useful to both URL and HTTP-Proto. They will also be likely useful to processing websocket handshake field values. It would be nice if I could put them in a separate repository with its own tests, documentation, and CI. But I don't know that this is enough meat on the bone so to speak, to justify as a complete new Boost library offering. When Boost.URL returns a std:::string the user has the option of providing a custom allocator. The library comes with this interface which uses a local stack buffer: <https://github.com/CPPAlliance/url/blob/111b83cc4726f3144194dc3546e096d60ac…> This can be used to avoid dynamic allocation when, for example - you want to apply decoding to a URL-encoded input, which happens often. Boost.HTTP-Proto would benefit from this class as well. Again we have the case of a common component that belongs in a separate repository. But this allocator isn't really related to the BNF-processing utilities mentioned above. So where would it go? As I use MSVC exclusively for regular development, I have put together a small unit test facility which is tailored to my workflow: <https://github.com/vinniefalco/http_proto/blob/9d3144c60b3426509b45cc63dbb3…> This has the flavor of Boost lightweight test, but also: * Redirects output to the Visual Studio IDE if a debugger is attached * Supports the model where one executable is built which holds all the tests * A command-line argument facility to specify individual test suites to run I use this in all of my Boost libraries and to-be-proposed libraries. I wouldn't say that it is user-facing. Currently I put a copy of the file in each library but I have made some changes and it would be better if I could put it in a shared place in the Boost tree. But it isn't public so it shouldn't be grouped with the BNF and the allocator stuff above. I am working on new libraries which do ASIO networking, and they use this handy mocking class which is used for testing stream algorithms: <https://github.com/boostorg/beast/blob/21cd552399aa8167ed53c21a74f3711c2c31…> This is a public interface, which users deploy for their own tests (for example the windows-tls project uses it). Again the case where I want to use it in tests for my own new libraries but without making a copy of the source. In other words in its own shared place. It does require ASIO, so I'm not sure it should be grouped with the rest of the stuff above. Now going back to these new libraries, I have Boost.HTTP-Proto which is a brand new library that speaks HTTP/1 but you have to bring your own networking. It is purely a low-level protocol library, but with a scope expanded from Beast to support more useful things that users need. Since networking is obviously needed I am developing the companion library Boost.HTTP-IO in parallel which uses ASIO to drive the protocol library. They use separate repositories and thus the protocol library is physically isolated, has its own tests, CI, and documentation, and so forth. There is a cosmetic issue where users have to write boost::http_proto::request if they want to declare a request container but then they have to write boost::http_io::write if they want to send the request over a socket (note the different namespaces). This is kind of annoying, and becomes even more annoying when you have to remember which namespace the error constant is located in: http_proto::error::end_of_message or http_io::error::end_of_file. One possibility is for these libraries to use the same namespace: boost::http. Or boost::http_proto. But this breaks the rule of one-repository, one-unique-namespace. Once these libraries are done I will at some point want to write Boost.Websocket-Proto and Boost.Websocket-IO which are similar to their HTTP counterparts (*). And then we will have twice the number of namespaces and error constant enums: boost::http_proto boost::http_io boost::websocket_proto boost::websocket_io and boost::urls These all have their own error enums called "error". If we create a separate repository for common code that all 5 of these libraries use, then that's a sixth namespace also with error code. Okay so that's the stuff that I've been pondering as I write this new code, are any of these real problems? What can I do about it? I'm interested in your thoughts. * The purpose of writing these new, seemingly duplicative libraries is to build on the experience of Beast to smooth out the discovered rough edges and provide a superior interface and implementation. -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

1 0

Any reason to not add asynchronous sink version of boost::log::add_file_log?
by Nicholas Neumann 19 Aug '21

19 Aug '21

The boost::log::add_file_log function in <boost/log/utility/setup/file.hpp> is a nice function for setting up a file sink. I had been using it and needed to switch from a synchronous frontend to an asynchronous one. But the sink returned is synchronous. Is there any reason to not add a version of the function which creates and returns an asynchronous frontend? Perhaps called something like add_async_file_log?

1 0

Master Branch now open for merging
by Marshall Clow 15 Aug '21

15 Aug '21

No restrictions; the release calendar is up to date. https://boost.org/development <https://boost.org/development> Next milestone: 20-Oct Boost 1.78.0 closed for new libraries and breaking changes — Marshall

1 0

Want to contribute
by Neeraj Khatri 15 Aug '21

15 Aug '21

Can I get help from the organization that how shall I start my contribution in this organization. Thank You ................ .........

1 0

[Boost.Units] Runtime Unit Conversions
by C.D. Clark 15 Aug '21

15 Aug '21

Good day, I have been using Boost.Units for several years now, and it is a great library. I find it difficult to write code without it anymore. However, it does not do runtime unit conversions, so I write a little library that does https://github.com/CD3/UnitConvert It uses Boost.Spirit to parse strings into quantities, and was an excuse for me to learn about spirit. It supports create a boost::units::quantity<T> object from the runtime quantity. Would anybody be interested in adding this type of capability to the boost unit library? I am not a computer scientists, so I don't believe I would be able to propose something up to the boost standard on my own. cdclark -- C.D. Clark III, PhD Associate Professor Department of Physics Fort Hays State University 600 Park Street Hays, KS 67601 Ph: 785.628.4502

2 1

I would like to add boost::algorithm::is_clamped, how to proceed?
by Ivan Matek 13 Aug '21

13 Aug '21

Hi, I would like to add is_clamped (that tests if the value is clamped, similar how we have std::is_sorted, std::sort). What would be the proper procedure? I have never committed to boost, so I have no access to any repository, no "contacts", so I have no idea if small proposals like this require just approval from owner or it needs broader discussion(for example in some cases it would be nice fix for missing chain comparison <https://www.geeksforgeeks.org/chaining-comparison-operators-python/> in core language, but then is_clamped name is not that nice, is_between might be nicer,...). Also I am not sure if this is the best place to ask for directions and do discussions, if you have some slack channel or forum you prefer please let me know. There was a proposal <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1440r0.html>for std::, but it is not in C++20. I have no relation to that proposal. regards, Ivan

3 8

is_constant_evaluated
by Robert Ramey 11 Aug '21

11 Aug '21

Any chance of seeing a feature macro for HAS_IS_CONSTANT_EVALUATED appearing in Boost.Config any time soon? Robert Ramey

8 20

[release] Boost 1.77.0 Release Candidate 1
by Marshall Clow 06 Aug '21

06 Aug '21

The first release candidates for the 1.77.0 release are now available at: <https://boostorg.jfrog.io/artifactory/main/release/1.77.0/source/> The SHA256 checksums are as follows: fc9f85fc030e233142908241af7a846e60630aa7388de9a5fafb1f3a26840854 boost_1_77_0_rc1.tar.bz2 f2dd9722b21450daf5ce8ef82c2d99c7ec304f913ee6c6b7f047d5639503dda1 boost_1_77_0_rc1.7z 5347464af5b14ac54bb945dc68f1dd7c56f0dad7262816b956138fc53bcc0131 boost_1_77_0_rc1.tar.gz d2886ceff60c35fc6dc9120e8faa960c1e9535f2d7ce447469eae9836110ea77 boost_1_77_0_rc1.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

3 3

[multiprecision/mpc][math/quadrature] Why boost::multiprecision::exp gets stuck when evaluating complex-valued integral?
by Kirill Kudashkin 05 Aug '21

05 Aug '21

Dear all, I have encountered a problem while using Boost C++ libraries ( multiprecision/mpc.hpp, math/quadrature) which I cannot resolve. This problems appears when running the following piece of code || |#include <boost/math/constants/constants.hpp> #include <boost/math/quadrature/exp_sinh.hpp> #include <boost/multiprecision/mpc.hpp> #include <boost/multiprecision/mpfr.hpp> #include <boost/math/special_functions/fpclassify.hpp> namespace mpns = boost::multiprecision; typedef mpns::number<boost::multiprecision::mpc_complex_backend <50> > mpc_type ; typedef mpc_type::value_type mp_type ; int main() { using boost::math::constants::root_pi ; mpc_type z{mp_type(1),mp_type(1)} ; auto f = [&](mp_type x) { //actually I did not test if all these conditions are needed... if (boost::math::fpclassify<mp_type> (x) == FP_ZERO) { return mpc_type(mp_type(1)) ; }; if (boost::math::fpclassify<mp_type> (x) == FP_INFINITE) { return mpc_type(mp_type(0)) ; }; mp_type x2 = mpns::pow(x,2U) ; if (boost::math::fpclassify<mp_type> (x2) == FP_ZERO) { return mpc_type(mp_type(1)) ; }; if (boost::math::fpclassify<mp_type> (x2) == FP_INFINITE) { return mpc_type(mp_type(0)) ; }; mpc_type ex2 = mpns::exp(-z*x2) ; if (boost::math::fpclassify<mpc_type> (ex2) == FP_ZERO) { return mpc_type(mp_type(0)) ; }; return ex2 ; } ; mp_type termination = boost::math::tools::root_epsilon <mp_type> () ; mp_type error; mp_type L1; size_t max_halvings = 12; boost::math::quadrature::exp_sinh<mp_type> integrator(max_halvings) ; mpc_type res = integrator.integrate(f,termination,&error,&L1) ; mpc_type div = 2U*mpns::sqrt(z) ; mpc_type result = (mpc_type(root_pi<mp_type> ())/div) - res ; return 0; } | ||Namely, the problem appears when evaluating the exponent. The code is compiled without any problems, but hangs on computing | mpc_type ex2 = mpns::exp(-z*x2) ;| It was possible to go into the function while debugging. It crashed eventually, when the compiler reached "unable to resolve non-existing file.../src/init2.c". I let it run for a while checking the call stack. It appears that the programs is stuck atcalling ___gmpn_sub_n_coreisbr(). Or better, in the call stuck it appeared frequently. I did several tests. The real-valued version (with mpfr_backend <2000>) works without any problems. cpp_complex_backend <100> works fine, but I could not test higher precision yet, since it is much slower. I found a work-around which is not ideal. Namely, mpc_type ex2 = mpc_type(mpns::exp(x2)) ; mpc_type ezx2 = mpns::pow(ex2,-z) ; works fine with mpc_complex_backend <2000>. The lambda-function as it is declared in the code above works and yields correct numbers. The problem appears when it is called from the integrator. My system. I use openSUSE Tumbeleweed. I installed boost libraries as provided by |boost_1_76_0-gnu-mpich-hpc-devel.| Complier -> g++, cppStandard gnu+17. I check that I have all libs, e.g. libgmp, libmpc, libmpfr and etc. All headers are present (the programs is complied without any warnings). Sorry for a lengthy question. Thank you in advance and Best wishes, Kirill ||

1 0

Reminder: The Master branch will be closing for the 1.77.0 release on WEDNESDAY 4-August
by Marshall Clow 04 Aug '21

04 Aug '21

Release calendar here: https://www.boost.org/development/index.html — Marshall

8 17

Re: [boost] Reminder: The Master branch will be closing for the 1.77.0 release on WEDNESDAY 4-August
by Gavin Lambert 03 Aug '21

03 Aug '21

On 3/08/2021 11:57 am, Andrey Semashev wrote: >> The docker image that the tools get run from doesn’t have “linux/magic.h” >> >> More as we discover it. > > I would like to know more about this issue. In particular, what Linux > system lacks this file (distro, kernel version, etc.). Maybe, this is > worth fixing before the release. Git history suggests that the file started existing in linux kernel 2.6.19 and remains since. Although it moved from one folder to another in the internal kernel source tree in kernel 3.7, but that shouldn't affect its existence in the userspace include dirs, unless something is using the wrong include paths.

3 3

Regexp performance guarantees
by Phil Endecott 30 Jul '21

30 Jul '21

Dear Experts, I recently wanted to add some input-sanitising code to a C++ web application, and as I had some existing Javascript code I decided to port its regex-based input checking to the C++ code. This didn't go as well as I had expected! Here's an example of the sort of thing I have: if (!regexp_match(s, regex("[A-Za-z0-9-_/]{1,8192}"))) throw MalformedInput(); The Javascript equivalent seems to be fine. In C++, with libstdc++'s regex implementation, it seems to take about 2 seconds to run. Boost.Regex didn't like the '-' after the '9' but when I fixed that the execution time became negligible. Boost.Xpressive seems also to be fast. On investigation it seems that this is due to there being two different algorithms, one of which (DFA) is linear in the string size but exponential in the pattern size (which in this case seems to mean exponential in the max repeat value of 8192), and the other (backtracking) is linear in the pattern size but exponential in the string size. It seems that the standard deliberately doesn't specify complexity guarantees for std::regex, leaving the choice of algorithm to the implementation. I find this a bit surprising. It's true that both algorithms have their strengths, but not knowing which you are going to get is the worst of both worlds - you would have to assume that it will be exponential in both pattern and string sizes in portable code! (Imagine a container that doesn't disclose whether it has vector or list complexity!) So I'm wondering if it would be useful for regex libraries to somehow be explicit about which algorithm they are and what the complexity is. Compare, for example, with the text search algorithms (Boyer-Moore etc) which indicate the algorithm in their names. Could we have regex_dfa / regex_backtracking, or something? Now having said that, I think that what I really need for my application is something that is worst-case linear in both the pattern size and the input string. I'm not sure if the apparently-fast Boost.Regex algorithm has a worst-case input that is slow. ("Regular Expression Denial Of Service"). It's clear that my example can be written without a regex as a simple linear loop, and maybe some regex libraries have heuristics that do that. Thoughts anyone? Regards, Phil.

8 13

[release] 1.77.0 post-beta merges
by Marshall Clow 30 Jul '21

30 Jul '21

The master branch is is now open for post-beta merges, but only as described in the Post-Beta Merge Policy. See <https://github.com/boostorg/wiki/wiki/Releases%3A-Beta-Merge-Policy> Reminder: The master branch closes for the release on Wednesday, August 4th. Full calendar here: https://www.boost.org/development/ <https://www.boost.org/development/> — Marshall P.S Doc changes and test changes do NOT require release manager approval to be merged.

5 13

Different Lib/CMake Layout between Pre-Build-Binaries and Build from source
by Dennis Luehring 26 Jul '21

26 Jul '21

target_link_libaries(... Boost::boost) seems not to work if the stagedir/<lib> folder is missing but the pre-build binaries missing this folder https://sourceforge.net/projects/boost/files/boost-binaries/1.75.0/ https://sourceforge.net/projects/boost/files/boost-binaries/1.75.0/boost_1_… boost_1_75_0 <boost> ... bootstrap.bat bootstrap.sh <lib64-msvc-14.1> <cmake> *.lib if i build 1.75.0 from source with b2 --toolset=msvc-14.1 --stagedir=./lib64-msvc-14.1 address-model=64 architecture=x86 link=static threading=multi i've get this hierachy c:\Boost\boost_1_75_0 <boost> ... bootstrap.bat bootstrap.sh ... <lib64-msvc-14.1> <-- stagedir <lib> <cmake> *.lib what is the very same hierarchy with Qt6 cmake-configs (so its seems to be "more" standard) C:\Qt\6.1.2 <msvc2017_64> <-- aka "stagedir" <lib> <cmake> Qt6*.lib why does the pre build binary package got a different hierarchy?

1 0

[bimap][PR RFC] Add std::initializer_list constructor
by Hu Jialun 23 Jul '21

23 Jul '21

C++11 allows list initialization for classes. STL map has been added a constructor with the signature map(initializer_list<value_type> il, const allocator_type& alloc = allocator_type()); Added a similar constructor to bimap, allowing for initialization in the form of initializer list, such as boost::bimap<double, long> tdn { {114.514, 1919}, {891.931, 810} }; --- Seems that the pull request is not being seen for a while... Could someone please take a quick look at it and possibly give some directions? :) https://github.com/boostorg/bimap/pull/31 include/boost/bimap/bimap.hpp | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/include/boost/bimap/bimap.hpp b/include/boost/bimap/bimap.hpp index 5fe7a3f..a3603e5 100644 --- a/include/boost/bimap/bimap.hpp +++ b/include/boost/bimap/bimap.hpp @@ -265,6 +265,29 @@ class bimap {} + #ifndef BOOST_NO_CXX11_HDR_INITIALIZER_LIST + bimap(std::initializer_list<BOOST_DEDUCED_TYPENAME base_::core_type::value_type> init, + const allocator_type& al = allocator_type()) : + + base_::relation_set( + ::boost::multi_index::get< + BOOST_DEDUCED_TYPENAME base_::logic_relation_set_tag>(core) + ), + + core(init,ctor_args_list(),al), + + left ( + ::boost::multi_index::get< + BOOST_DEDUCED_TYPENAME base_::logic_left_tag>(core) + ), + right ( + ::boost::multi_index::get< + BOOST_DEDUCED_TYPENAME base_::logic_right_tag>(core) + ) + + {} + #endif + bimap(const bimap& x) : base_::relation_set(

1 0

CMake: using boosts own package finding stuff, howto?
by Dennis Luehring 19 Jul '21

19 Jul '21

in short: CMake does need to change (i'll need to wait for updates) to support newer released boost versions i've heard that Boost supports cmake now directly but i don't get the direct cmake support of boost working with my CMakeLists.txt i know that CMake supports 1.75 in the lastest releases directly but 1.76 and 1.77 are still not on the list and i don't want to wait for CMake release to test new features/betas etc. my system: Ubuntu 21.04/x64, CMake 3.19.4/3.21.0, GCC 10.x Boost 1.75 (want to upgrade to 1.76 soon) my boost build: mkdir ~/dev/3rdparty-liux-gcc cd ~/dev/3rdparty-linux-gcc wget https://dl.bintray.com/boostorg/release/1.75.0/source/boost_1_75_0.tar.bz2 tar -xf boost_1_75_0.tar.bz2 ln -s boost_1_75_0 ./boost cd boost_1_75_0 ./bootstrap.sh ./b2 --toolset=gcc cxxflags=-fPIC --build-dir=./_build address-model=64 architecture=x86 link=static threading=multi --with-graph --with-nowide --with-test --width-config --with-system --with-filesystem --stagedir=./_x64 ln -s _x64/lib lib my simple test hierarchy: boost_using_cmake_tests boost_using_cmake_tests\_build boost_using_cmake_tests\boost_using_cmake boost_using_cmake_tests\boost_using_cmake\CMakeLists.txt cmake_minimum_required (VERSION 3.16) set(Boost_NO_BOOST_CMAKE TRUE) set(Boost_NO_SYSTEM_PATHS TRUE) project (using_boost_with_cmake) set( MY_THIRD_PARTY_LIBS "~/dev/3rdparty-linux-gcc" ) set( BOOST_ROOT ${MY_THIRD_PARTY_LIBS}/boost ) set( BOOST_INCLUDEDIR ${BOOST_ROOT}/boost) set( BOOST_LIBRARYDIR ${BOOST_ROOT}/lib) find_package(Boost REQUIRED COMPONENTS unit_test_framework filesystem system) cmake run: using 3.19.4 cmake without 1.75 support ~/dev/boost_using_cmake/_build$ ../../cmake-3.19.4-linux-x86_64/bin/cmake ../boost_using_cmake/ -- The C compiler identification is GNU 10.3.0 -- The CXX compiler identification is GNU 10.3.0 -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working C compiler: /usr/bin/cc - skipped -- Detecting C compile features -- Detecting C compile features - done -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Check for working CXX compiler: /usr/bin/c++ - skipped -- Detecting CXX compile features -- Detecting CXX compile features - done CMake Warning at /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1204 (message): New Boost version may have incorrect or missing dependencies and imported targets Call Stack (most recent call first): /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1326 (_Boost_COMPONENT_DEPENDENCIES) /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1935 (_Boost_MISSING_DEPENDENCIES) CMakeLists.txt:14 (find_package) CMake Warning at /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1204 (message): New Boost version may have incorrect or missing dependencies and imported targets Call Stack (most recent call first): /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1326 (_Boost_COMPONENT_DEPENDENCIES) /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1935 (_Boost_MISSING_DEPENDENCIES) CMakeLists.txt:14 (find_package) CMake Warning at /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1204 (message): New Boost version may have incorrect or missing dependencies and imported targets Call Stack (most recent call first): /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1326 (_Boost_COMPONENT_DEPENDENCIES) /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1935 (_Boost_MISSING_DEPENDENCIES) CMakeLists.txt:14 (find_package) -- Found Boost: /home/linux/dev/3rdparty-linux-gcc/boost (found version "1.75.0") found components: unit_test_framework filesystem system -- Configuring done -- Generating done -- Build files have been written to: /home/linux/dev/boost_using_cmake_tests/_build it works but cmake 3.19.4 is missing direct support for 1.75 so its some way "unsupported", cmake does not detect the correct lib names automaticly, only some styles are working etc. i've talked about the problem on the cmake forum and the answer was https://discourse.cmake.org/t/fail-to-use-self-build-boost-1-75-under-ubunt… Brad King: "...However, Boost upstream now provides a proper CMake package file BoostConfig.cmake which should work for using Boost in any layout..." 1.75 is now directly supported by cmake - but now i want to use 1.76 and the problem re-occures i've tried serveral things to force cmake to use the boost own package findings stuff without any success i hope its possible to use 1.75 and 1.76 in the future without always wait for cmake to support it directly any hints what changes are needed with my CMakeLists.txt to support boost own cmake package finding (and get rid of these problems)?

4 17

boost still supports C++03?
by Oliver Kowalke 19 Jul '21

19 Jul '21

Hi, does boost still support Cpp03 or is Cpp11 the min. standard? Oliver

6 10

[1.77][multi_index] post-beta merge request
by Joaquin M López Muñoz 17 Jul '21

17 Jul '21

Hi, I'd like to merge this commit (only testing code and docs affected): https://github.com/boostorg/multi_index/commit/3dad7f38a44783c297b2d477cba2… This is a trivial change for C++23 forward compatibility (and C++<23 UB avoidance), as explained in https://github.com/boostorg/multi_index/issues/45 Best, Joaquín M López Muñoz

2 2

Integrating Boost into client project build via FetchContent
by Stefan Heinzmann 16 Jul '21

16 Jul '21

Hi all, the recent activity regarding adding CMake support to some remaining libraries (many thanks go to Peter Dimov), encouraged me to try using FetchContent to integrate Boost into client projects. I'm sure many people are interested in such a possibility in order to reduce dependencies on the build environment. The brief result seems to be: It almost works. Enough to make it interesting. The reason for my message is to ask if this is supposed to work, i.e. if I am trying something that should work, either now or in the near future, or if it is a frivolous expectation on my part. A toy project's CMakeLists.txt might look like this: ============================================================= cmake_minimum_required(VERSION 3.21) project(boost_test) include(FetchContent) set(BOOST_ENABLE_CMAKE ON) FetchContent_Declare(build_boost GIT_REPOSITORY https://github.com/boostorg/boost.git GIT_TAG boost-1.77.0.beta1 ) FetchContent_GetProperties(build_boost) if(NOT build_boost_POPULATED) FetchContent_Populate(build_boost) add_subdirectory( ${build_boost_SOURCE_DIR} ${build_boost_BINARY_DIR} EXCLUDE_FROM_ALL ) endif() add_executable(boost_test boost_test.cpp) target_link_libraries(boost_test PRIVATE Boost::format) ============================================================= The corresponding source file would look like this: ============================================================= #include <boost/format.hpp> #include <iostream> int main() { std::cout << boost::format("Hello %1%!") % "everybody"; } ============================================================= I used the CMake GUI version 3.21.0 on Windows 10 to configure the project for Visual Studio 2019 Release 16.10.3 with a 64-bit build. It produced lots of install-related errors in the generation phase, but it nevertheless pruduced a solution that successfully built the project. Now, there are of course a couple of issues, which I'd like to get your opinion on: 1. Optimized source download As listed, FetchContent pulls in the entire boost sources, regardless whether they're needed or not. This takes a significant amount of time and uses a lot of disk space for no benefit. Clearly, you would want to fetch only the sources you need, but there doesn't seem to be a good way to handle the dependencies between the various boost libraries. You could use the GIT_SUBMODULES option of FetchContent, but you'd need to list not only the libraries you directly use (Boost::format in my example above), but you also need to list the dependencies of those, which is tedious and brittle. I imagine that this can be handled via a special tool that gets invoked as a PATCH_COMMAND, which is able to scan through the submodules that have been populated and populates all its dependencies. I haven't seen such a tool anywhere, but maybe somebody has got a solution already? 2. Dealing with install Obviously, when using Boost like this, I don't want it to add installation items into the install of my own project, therefore I used the option EXCLUDE_FROM_ALL of add_subdirectory(). That doesn't eliminate all of the problems, as is evidenced by the myriad install-related errors that CMake flags up. Do you have an idea how to properly deal with that? I'm slightly out of my depth here. If you want to check this on your system, the CMake errors may prevent building. I have been able to build when generating a Visual Studio solution, but not when I openend the folder in Visual Studio directly, relying on Visual Studio's own CMake support. Of couse, if you have other suggestions, please tell! Cheers Stefan Heinzmann

2 1

[1.77] Requesting post-beta merges
by John Maddock 15 Jul '21

15 Jul '21

I have some late changes I'd like to merge to master if possible: For multiprecision, it's basically a single bug fix (for https://github.com/boostorg/multiprecision/issues/342) details here: https://github.com/boostorg/multiprecision/pull/344, note that the single CI failure is spurious. For Math, the collected changes are here: https://github.com/boostorg/math/pull/661 The really big changes here are documentation, the remaining issues fixed are documented in the PR above. There is one further change for Math, that I've neglected to cherry pick to the PR above, but it's this one: https://github.com/boostorg/math/pull/659 which fixes some invalid code that had slipped through. Many thanks! John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 2

[1.77] Permission to merge to master
by Andrey Semashev 15 Jul '21

15 Jul '21

Hi, I'd like to merge the following changes to master: https://github.com/boostorg/filesystem/commit/003f00239963e4b270a47d7e78664… https://github.com/boostorg/filesystem/commit/9e5a3e231e5a5d3c501447ca307a3… Fixes Boost.Filesystem compilation for Android and Mac OS. https://github.com/boostorg/utility/commit/6cca23a63a1c038b9afc261037548b78… Removes dependency of Boost.Utility on Boost.ContainerHash.

2 1

Master branch now closed for 1.77.0 beta release
by Marshall Clow 14 Jul '21

14 Jul '21

Please do not make any commits to the master branch. — Marshall

2 1

[release] Boost 1.77.0 beta 1 released
by Marshall Clow 14 Jul '21

14 Jul '21

Boost release 1.77.0 beta 1 is now available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.77.0.beta1/source/> The SHA256 checksums are as follows: 1aba2bf9416d71026c9e6bbd10a2b7cfb31b0950baa7ad0861dfb74984d96bd9 boost_1_77_0_b1.zip 55126d149664541ffc9fd1f41b2ec67146d69bdab92e41da4bb8610b755ca9ec boost_1_77_0_b1.7z 1aabe7704e91f4f8d97b81d03ddc21c3396f4b72fc4041f01bfcfc128bac0d73 boost_1_77_0_b1.tar.gz 3d5801790c96d2bc9ed23372c4f9fd963bc2f39fe540e35d7b4fe586ba77dfa7 boost_1_77_0_b1.tar.bz2 For details of what's in the release, see <https://www.boost.org/users/history/version_1_77_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

1 0

boost.python compilation error (newbie)
by maths soso 11 Jul '21

11 Jul '21

I'm new to boost, I decided installing it by following instructions provided at SO: https://stackoverflow.com/a/24086375/10213771 (The only difference is that I used version 1.76) Everything went fine, then I decided to compile this C++ file: char const* greet(){ return "hello, world";} #include <boost/python.hpp> BOOST_PYTHON_MODULE(hello_ext){ using namespace boost::python; def("greet", greet);} Since boost.python is not header only library, I needed to link to it on compilation, I used the following compile command: g++ -I ~/Desktop/boost_1_76_0/ -I /usr/include/python2.7/ main.cpp -o prog ~/Desktop/boost_1_76_0/stage/lib/libboost_python27.a but I get the following errors: /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start': (.text+0x24): undefined reference to `main' /usr/bin/ld: /home/sofiane/Desktop/boost_1_76_0/stage/lib/libboost_python27.a(registry.o): in function `boost::python::converter::registration::get_class_object() const': ... /usr/bin/ld: function_doc_signature.cpp:(.text+0x1de): undefined reference to `PyObject_IsTrue' /usr/bin/ld: function_doc_signature.cpp:(.text+0x23e): undefined reference to `PyInt_FromLong' /usr/bin/ld: function_doc_signature.cpp:(.text+0x28b): undefined reference to `PyInt_FromLong' ...

3 2

[release] Boost 1.77.0 Beta 1 Release Candidate 1 is available
by Marshall Clow 10 Jul '21

10 Jul '21

The first release candidates for the 1.77.0 beta release are now available at: https://boostorg.jfrog.io/artifactory/main/beta/1.77.0.beta1/source/ 1aba2bf9416d71026c9e6bbd10a2b7cfb31b0950baa7ad0861dfb74984d96bd9 boost_1_77_0_b1_rc1.zip 55126d149664541ffc9fd1f41b2ec67146d69bdab92e41da4bb8610b755ca9ec boost_1_77_0_b1_rc1.7z 1aabe7704e91f4f8d97b81d03ddc21c3396f4b72fc4041f01bfcfc128bac0d73 boost_1_77_0_b1_rc1.tar.gz 3d5801790c96d2bc9ed23372c4f9fd963bc2f39fe540e35d7b4fe586ba77dfa7 boost_1_77_0_b1_rc1.tar.bz2 The web site has NOT YET been updated. As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

3 3

The Master branch will be closing for the 1.77.0 beta release TODAY!
by Marshall Clow 07 Jul '21

07 Jul '21

If you have changes for the beta, they need to be merged to master today. See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release managers

1 0

The deadline for Major changes for Boost 1.77.0 is TODAY!
by Marshall Clow 04 Jul '21

04 Jul '21

See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release Managers

4 6

Poor performance on windows with logging sinks::file_collector when two file logs use same directory. Thoughts?
by Nicholas Neumann 24 Jun '21

24 Jun '21

I've got two different rotating file logs that point to the same directory (with different file name patterns). Is this in general just a bad idea? They end up sharing the same file_collector, which seems wrong, so perhaps that is a clue that I shouldn't have my logs set up like this. In production I've got a service that compresses, archives, and manages the size of the logs. But in dev, I don't, so the number of files in the directory slowly grew. But the startup time for my program grew much faster. On windows the scan_for_files function in the collector has a loop that is O(mn), where m is the number of files in the directory, and n is the number that matched in previous calls to the scan_for_files function This means the scan_for_files for the first rotating file log in the directory has no issue (n is 0), but the second can be problematic. It iterates over the files in the directory and for each file in the directory, it calls filesystem::equivalent on all of the matches from previous scan_for_files calls. On windows, filesystem::equivalent is particularly heavy, opening handles to both files. Thoughts? Is the two file logs getting the same collector the real issue? Or is it my pointing two file logs to the same directory? I see some ways to mitigate the slowdown in scan_for_files - e.g., filesystem::equivalent could be called after all of the method/match_pattern check, but the two file logs sharing the same collector feels like the real issue.

3 3

The deadline for new libraries and breaking changes in Boost 1.77.0 is this Wednesday, June 23
by Marshall Clow 21 Jun '21

21 Jun '21

See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release Managers

1 0

Re: [boost] What has become of John Maddock's implementation of the Remez algorithm for Chebychev approximation?
by Bjorn Reese 18 Jun '21

18 Jun '21

On 6/15/21 11:48 PM, Joachim Wuttke via Boost wrote: > Until v1.53, Boost Math had doc pages [1,2] on the Remez algorithm. > This algorithm [3] computes the coefficents of the Chebyshev polynomial > that approximates a given function. Page [2] refers to actual code In addition to John's reply, I wanted to add that Boost.Math has direct support for Chebyshev polynomials now: https://www.boost.org/doc/libs/release/libs/math/doc/html/math_toolkit/sf_p…

4 5

What has become of John Maddock's implementation of the Remez algorithm for Chebychev approximation?
by Joachim Wuttke 16 Jun '21

16 Jun '21

Until v1.53, Boost Math had doc pages [1,2] on the Remez algorithm. This algorithm [3] computes the coefficents of the Chebyshev polynomial that approximates a given function. Page [2] refers to actual code in directory libs/math/minimax. This code can still be found on GitHub [4], but maintenance status and dependences are unclear. Anybody around who knows anything about this code? Kind regards, Joachim [1] https://www.boost.org/doc/libs/1_53_0/libs/math/doc/sf_and_dist/html/math_t… [2] https://www.boost.org/doc/libs/1_53_0/libs/math/doc/sf_and_dist/html/math_t… [3] https://en.wikipedia.org/wiki/Remez_algorithm [4] https://github.com/boostorg/math/tree/develop/tools/minimax -- Dr. Joachim Wuttke group leader Scientific Computing Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science at MLZ https://computing.mlz-garching.de https://jugit.fz-juelich.de/mlz

2 1

Using Boost.Test header-only from CMake
by Peter Dimov 15 Jun '21

15 Jun '21

Some libraries (I encountered this when porting the tests of Signals2) use Boost.Test in header-only mode, by including <boost/test/included/unit_test.hpp> without linking to anything. This worked in the "legacy" structure where all headers are always available, but doesn't work under CMake where you have to link to header-only libraries in order to get the proper include path. Should we make an attempt to support this use by declaring a special header-only target in Boost.Test (e.g. Boost::included_unit_test), or is that a waste of time? One can as well link to the proper Boost::unit_test_framework (and then even use it header-only, although there's not much point in doing so.) I'm inclined towards "waste of time".

10 34

Re: [boost] boost-json apt-get packge
by Vollaro, John 14 Jun '21

14 Jun '21

Date: Fri, 11 Jun 2021 01:42:18 +0300 From: "Peter Dimov" <pdimov(a)gmail.com> To: <boost(a)lists.boost.org> Subject: Re: [boost] boost-json apt-get packge Message-ID: <05f001d75e49$decba2f0$9c62e8d0$(a)gmail.com> Content-Type: text/plain; charset="utf-8" Vollaro, John wrote: > Is their a apt package that includes boost-json? For what distro? debian > This apt packages did not include boost-json > > apt-get install libboost1.76-all-dev Should be libboost1.76-json-dev. Could not find this package. This e-mail, including attachments, may include confidential and/or proprietary information, and may be used only by the person or entity to which it is addressed. If the reader of this e-mail is not the intended recipient or his or her authorized agent, the reader is hereby notified that any dissemination, distribution or copying of this e-mail is prohibited. If you have received this e-mail in error, please notify the sender by replying to this message and delete this e-mail immediately.

2 1

CMake minimum version to support
by Peter Dimov 11 Jun '21

11 Jun '21

I suppose the time has come to have the discussion on the minimum CMake version we will support for building Boost. Currently that's set to 3.5, which kind of works, but is fairly inconvenient. The interesting options are - CMake 3.8: required for use of the compile features cxx_std_11, cxx_std_14, cxx_std_17, etc. Also allows source_group(TREE, which is used by Json and PropertyTree. - CMake 3.9: required by Nowide, I'm not sure why. Also, required for FindMPI to define an imported target. Building Boost.MPI is optional though. - CMake 3.13: required for Boost installation support. - CMake 3.14: required for FindPython to be modern enough to make building Boost.Python reasonably easy. (Building Boost.Python is optional, though.) There are also less important nice-to-have things such as - CMake 3.10: adds include_guard() - CMake 3.12: adds CONFIGURE_DEPENDS to file(GLOB - CMake 3.15: adds VERBOSE/DEBUG to message( Opinions?

15 40

boost-json apt-get packge
by Vollaro, John 10 Jun '21

10 Jun '21

Is their a apt package that includes boost-json? This apt packages did not include boost-json apt-get install libboost1.76-all-dev ____________________________ John Vollaro 185 Asylum St 6th Floor, Hartford, CT 06103 O: 860-702-8563 | M: 860-919-9443 | john.vollaro(a)optum.com<mailto:john.vollaro@optum.com> This e-mail, including attachments, may include confidential and/or proprietary information, and may be used only by the person or entity to which it is addressed. If the reader of this e-mail is not the intended recipient or his or her authorized agent, the reader is hereby notified that any dissemination, distribution or copying of this e-mail is prohibited. If you have received this e-mail in error, please notify the sender by replying to this message and delete this e-mail immediately.

2 1

Re: [boost] Using Boost.Test header-only from CMake
by Glen Fernandes 10 Jun '21

10 Jun '21

On Sun, Jun 6, 2021 at 9:51 PM Peter Dimov wrote: > For completeness, the libraries using the deprecated boost/test/minimal.hpp are: > > foreach > graph > graph_parallel > iterator > logic > numeric/conversion > numeric/interval > property_map > tokenizer > units > yap > > These need to migrate to either LWT or the non-deprecated Boost.Test. I've migrated all of the above to LWT. Graph is still a PR that needs to be merged. Glen

1 0

Fwd: Interested in contribution to this organisation.
by Chandrakant Jena 16 09 Jun '21

09 Jun '21

---------- Forwarded message --------- From: Chandrakant Jena 16 <chandrakant.barcelona(a)gmail.com> Date: Wed, Jun 9, 2021 at 9:47 AM Subject: Interested in contribution to this organisation. To: <boost(a)lists.boost.org> hello devs, I am chandrakant jena currently studying computer science in utkal university, bhubaneshwar,Odisha. my current interest is c++ and I found this organisation really interesting and suitable for me. I want to know how can I get started? here are some of my profile links: linked in: https://www.linkedin.com/in/chandrakant-jena-5aab131a7/ github profile: https://github.com/chandrakant100

2 1

[cmake] Problem with dependencies for configure checks
by Andrey Semashev 08 Jun '21

08 Jun '21

Hi, I've been having this problem with CMake in Boost.Filesystem, where I need to have the Boost::library targets available before Boost::filesystem target is defined. This is needed in order to perform configuration checks that will affect how Boost::filesystem will be defined. For example, see the check_cxx_source_compiles calls: https://github.com/boostorg/filesystem/blob/af6ac28b5785820b93a2af7dd6e9b80… For the check_cxx_source_compiles calls, I would have liked to add targets like Boost::config and Boost::winapi to CMAKE_REQUIRED_LIBRARIES so that the checks are compiled with include directories of those dependencies added in the command line. This doesn't work because these targets may not be defined at the point when the configuration checks are performed. My current workaround, as you can see, is to add the Boost root to CMAKE_REQUIRED_INCLUDES, where the boost directory with the common headers tree is located. However, this will not work if we're going to make that directory optional or remove it. Also, you can see that I'm reusing checks implemented in Boost.Config, for which I also had to hard code its relative location from Boost.Filesystem. If we're going to allow different libraries located in separate directory trees, this will also break. My question is, can this be fixed and how? I was wondering if it is possible to make the target generation two-stage, where the first stage identifies library locations, including directories with their headers, and the second stage would define build targets. This way all library directories would be available to the second stage. Although I can already see the problem with second order dependencies with this approach...

5 34

CMake progress report
by Peter Dimov 06 Jun '21

06 Jun '21

At the moment, we're down to the following libraries missing CMake support on develop: asio locale log numeric/odeint numeric/ublas parameter_python python sync I've asked Chris how we can proceed with adding a CMakeLists.txt file to ASIO so that we can unblock Log (and Beast.) In addition, the following libraries are currently disabled as having incompatible CMakeLists.txt files in their root directories: beast callable_traits compute gil hana hof safe_numerics static_string stl_interfaces yap I'm working on documenting the CMake support infrastructure, but I'm not done yet.

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Best way to hash_combine a bool?
by John Maddock 05 Jun '21

05 Jun '21

What's the best way to combine a hash value with a bool? Specifically, if you're generating a hash value for a class which has a one member a bool. Normally I would just boost::hash_combine all the class members together, but doing that with a bool member leads to: 1>d:\data\boost\boost\boost\multiprecision\detail\hash.hpp(20,88): warning C4805: '^': unsafe mix of type 'T' and type 'size_t' in operation 1> with 1> [ 1> T=bool 1> ] Followed by a long instantiation backtrace (this is from Boost.Multiprecision). Since there's only one bool in this class, I could just apply a unary ~ to the value when the bool is true, but obviously that wouldn't work for classes with multiple bool's. Should we modify hash_combine for this use case? Cheers, John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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license violations
by tom.beacon 03 Jun '21

03 Jun '21

To whom should possible license violations be reported? Sent with [ProtonMail](https://protonmail.com) Secure Email.

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Reviewing my first file transfer using Asio
by Farbod Ahmadian 01 Jun '21

01 Jun '21

Hi everyone, I was learning Boost.Asio recently and to learn by doing a project, I decided to write a simple file transfer. So I wrote an *Async TCP Server* and a *Sync TCP Client; *you can use a client to send any kind of file to the server. This is how it works: 1) Clients connect to the server. 2) Clients send the file name to the server. 3) If everything is okay, the server will return an "OK" to that client and wait for that client to send the file. 4) If the client received "OK", it'll send the file. 5) If everything goes well, the file is received by server and the connection will be closed. I will attach the source codes in this email. So here are my questions: 1) Would you mind please review my code and say the problems? I'm a newbie in Asio ;) 2) How to make my client and server talk with a special protocol? Let's say HTTP. (If a socket server understands HTTP, will it be a web server? something like Nginx and Apache.) 3) What is the next step? How can I improve this? What should I learn/do next? Anything is kindly appreciated :) With best regards, Farbod

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Adding CMakeLists.txt files
by Peter Dimov 31 May '21

31 May '21

I'm adding CMakeLists.txt files (mostly generated by `boostdep --cmake <libname>` to libraries that don't have one yet. Apologies (in advance) to all the maintainers for not going through the proper procedure, but this is much easier done in bulk (and order matters).

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Tool maintenance
by Edward Diener 27 May '21

27 May '21

There is a list of maintainers for Boost libraries at libs/maintainers.txt. Is there likewise a list of maintainers for Boost tools ? I have discovered a serious bug with BoostBook and nested namespaces, created an issue, but fear that no one will respond. I would like to e-mail anybody who is a maintainer for BoostBook who might be able to look at the issue and fix it, but there is no list of maintainers for Boost tools which I can find. The person who appears to have worked with BoostBook in the past, Daniel James, is no longer active with Boost so I have no idea who might be able to fix the issue.

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Develop Regression Tests Failing
by Tom Kent 26 May '21

26 May '21

Since sometime yesterday, all the gcc/clang develop runners I maintain (not sure about Visual Studio, that machine has been down for updates) have been failing, before the tests suite can even start running. Master still looks good. They end with the following: - bzip2 : yes [30] - lzma : yes [30] - zstd : no [30] - lzma : yes (cached) [30] - has_lzma_cputhreads builds : no [2] - auto_ptr : yes [3] error: Unable to find file or target named error: '/python//numpy' error: referred to from project at error: '../libs/python/build' I believe this is because of the python ( https://github.com/boostorg/python/pull/362) and build ( https://github.com/boostorg/build/pull/726) pull requests that were merged in around that time. The question is, why is this causing an issue....I have some vague memory of the regression test suite always using build from master? Am I remembering this correctly? If so, I think we may need to back out the python change until build's develop branch merges to master? I'm seeing this across multiple docker images, one that has been rather stable is this: https://hub.docker.com/layers/teeks99/boost-cpp-docker/clang-11/images/sha2… running with this user-config.jam: https://github.com/teeks99/boost-cpp-docker/blob/master/clang-11/user-confi… and numpy installed for both python 2 and 3. Thoughts? Tom

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[boostbook] Doxygen nested namespaces entities not being handled
by Edward Diener 20 May '21

20 May '21

I am seeing an issue where nested namespace doxygen documented entities are not being generated by BoostBook for the final documentation of a reference section in a library's documentation. I am using the quickbook -> boostbook -> html set of tools in the doc jamfile. If I just use doxygen directly to generate the documentation the nested namespace entities are there, so this appears to be a BoostBook problem. Has this problem always existed ? Has anyone else ever encountered it ? I first reported this as a Boost Build issue at https://github.com/bfgroup/b2/issues/18, but then reported this at https://github.com/boostorg/boostbook/issues/10.

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Boost Governance?
by René Ferdinand Rivera Morell 18 May '21

18 May '21

A disclaimer: I write this solely as a Boost Library author. And not in any other capacity or representing any other interest. It's now been at least a year since Boost switched from the Software Freedom Conservancy to the Boost Foundation for its governance organization. But have people noticed any difference? Did you know that switch happened? Did you know that they held an election for the Board of Directors and for the Officers? Do you know when that election happened? Do you know who got elected? Do you know how they were selected? Do you know what their responsibilities are? Do you know what their bylaws are? Do you know their financials? More importantly: Did you answer "no" to any of those questions? As a library author, I can say I definitely answered no to many of those questions. This is a problem. As authors, without asking, we should know those answers from the organization that governs our work. We should have input into how that organization governs. In other words, we deserve open and transparent governance; not the closed and opaque status quo. -- -- René Ferdinand Rivera Morell -- Don't Assume Anything -- No Supone Nada -- Robot Dreams - http://robot-dreams.net

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Re: [boost] Boost Governance?
by Glen Fernandes 18 May '21

18 May '21

Rene wrote: > It's now been at least a year since Boost switched from the Software Freedom Conservancy to the Boost Foundation for its governance organization. 13:14 <glenfe> @grafikrobot The Software Freedom Conservancy never governed the Boost C++ Libraries, nor did the Boost Steering committee, nor does the Boost Foundation. Only the Boost community does that. 13:15 <grafikrobot> Hopefully you'll clarify that on the dev list. i.e. The "Boost Steering Committee"[1] became "Boost Foundation"[2]. [1] https://sites.google.com/a/boost.org/steering/home [2] https://sites.google.com/a/boost.org/steering/boost-foundation It still deals with the C++Now conference, providing the mailing lists, hosting, etc. But any decision making and governance of the Boost libraries is still the domain of the Boost community (i.e. you, me, and the other Boost library authors and maintainers). Glen

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[sync] Optimizing Boost's sync using futex2
by André Almeida 15 May '21

15 May '21

Hi there, I'm the author of futex2[0], a WIP new set of Linux's syscalls that allows userspace to write efficient sync mechanisms. I would like to hear from Boost's developers if the project would benefit from this new interface. >From Boost/sync's codebase, I can see that you are already familiar with futexes, but just in case: * What's futex? futex stands for "fast userspace mutexes". It's a syscall that basically exposes a wait queue, where userspace can ask to put threads to sleep and to wake them. The index of such queue is an unsigned int address (that is usually called a futex). It's value doesn't mean anything for the kernel, userspace is responsible to defining the rules of it and implementing the logic. * Why futex2? futex has long standing issues that seems impossible to be solved in the current interface, so we are designing a new set of syscalls taking those problems in account (more on that at [0]). It's not merged yet, and I'm researching some uses cases to validate and get feedback about the API. The new API has the following new features: * Variable sized futexes (6, 16, 32 and 64 bits): we aren't restrict to only 32 bits anymore, and this can be used for decreasing memory usage or to wait on an address * Wait for multiple futexes: this function enables userspace to wait on a list of futexes and wake on the first that triggers a wake. Our current use case for this is for game engines and to emulate WaitForMultipleObjects from WinAPI in Wine * NUMA-awarenes: current futex has a single global hash table that is allocated in some node. Every futex() call that happens on the other nodes will have a access penalty. At futex2, there'll be a single table per node, so you can specify which one you want to operate on to increase locality. The detailed description of the API can be seen in the documentation patch[1]. Do you think that Boost would benefit from it? Thanks, André - futex2 talk at OpenSource Summit: https://www.youtube.com/watch?v=eG6GMBTcPQ8 [0] https://lore.kernel.org/lkml/20210427231248.220501-1-andrealmeid@collabora.… [1] https://lore.kernel.org/lkml/20210427231248.220501-7-andrealmeid@collabora.…

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