March 2017 - Boost - lists.preview.boost.org

[release] 1.64.0 closed for Beta
by Rene Rivera 15 Mar '17

15 Mar '17

The master branch is now closed for all changes except by permission for the Beta release. Also, remember to add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_64_0.q… > Thanks, -- The Boost Release Team -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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[config] msvc-14.1 and C++14 constexpr
by John Maddock 13 Mar '17

13 Mar '17

So.... MSVC-14.1 (2017) sort of supports C++14 constexpr. However, it is also prone to internal compiler errors, and currently does not compile config_test.cpp unless we set BOOST_NO_CXX14_CONSTEXPR. Does anyone have a view on which way this macro should be set? Thanks, John. --- This email has been checked for viruses by AVG. http://www.avg.com

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Re: [boost] [gsoc17] Project1: Static map: Can I implement the competency test in g++-7?
by Vic Luo 13 Mar '17

13 Mar '17

Hi, During the implementation of my static_map, I recently encountered a problem: how to deal with string types? For example: constexpr auto cmap_str = make_static_map({ {"abc", 1}, {"bcd", 2} }); static_assert(cmap_str["abc"] == 1, "test"); In my implementation, KeyType requires 1. constexpr operator==, which is not provided by const char * 2. constexpr hash(const KeyType&). Since there is no such thing in standard library, I have to implement some in this project. Currently I would like to use string_view, since it looks like a general solution for compile-time string with lots of constexpr functions, but I don't know which of the following designs looks better: Design A: template<typename KeyType, typename MappedType, typename EqualOp = StaticEqualOp<KeyType>, typename HashOp = StaticHashOp<KeyType>> class static_map; // StaticEqualOp: Specialize StaticEqualOp for those KeyTypes that // can construct string_view and use operator== of string_view, // otherwise we simply use operator== of KeyType // StaticHashOp: size_t operator()(const string_view&, const string_view&) // for types that can construct string_view Design B: We don't specialize any StaticEqualOp for const char*. Instead, make_static_map({{"abc", 1}}) returns static_map<string_view, int> instead of static_map<const char *, int>. Which one is better? Or is there any more feasible design? Thanks, -- --------------------------------- Vic Luo Shanghai Jiaotong University Key fingerprint 0x98809ca08bf5662a

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[safe_numerics] The review is finished
by Andrzej Krzemienski 13 Mar '17

13 Mar '17

Hi Everyone, The review of safe_numerics library by Robert Ramey is now finished. Thanks to all participants for submitting their reviews, and sharing their insights. I will announce the result in the next couple of days. -- Andrzej Krzemienski, review manager

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[gsoc17] Project Static map : Clarifications and Competency test
by Pasindu Kanchana 13 Mar '17

13 Mar '17

Hi I am Pasindu Kanchana from Sri Lanka, studying at the University of Moratuwa as a final year undergraduate(4th year).I have worked as a developer intern for past 6 months for an exchange related company focusing c++ and have used boost memory mapped_file , tokenizer and filesystem. It would be really helpful if i get answers for the following 3 questions. A)Although the requested key is not in range ,still the code should compile?(without any error throwing and halting compilation) B)The solution to the problem should prove that compile time initiation of the map is confirmed(constexpr should definitely compile at the compile time not remain to the run time).would it be enough to practically proving this for different compilers under c++14 to approve as a solution? C)Should I take the competency test? Thank you.

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[outcome] Seeking review manager for Boost.Outcome
by Niall Douglas 13 Mar '17

13 Mar '17

It's only taken a month of work and writing my own C preprocessor, but I finally have a usable set of API reference docs for Outcome at https://ned14.github.io/boost.outcome/. Apart from a few docs glitches caused by the old version of doxygen on Travis, I'd say Outcome is ready for review. Would anybody be interested in review managing Outcome? Thanks, Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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[safe_numerics] Review
by Barrett Adair 12 Mar '17

12 Mar '17

Last minute review here. This will be short and sweet. > What is your evaluation of the design? I like it. The "drop-in replacement" approach is easy to understand. > What is your evaluation of the implementation? It's more complicated than I expected, but if it works, it works. I think the runtime checks in this library might be good candidates for BOOST_[UN]LIKELY. Are there test cases for post decrement? The implementation appears to return a reference to local: https://github.com/robertramey/safe_numerics/blob/master/include/safe_base.… safe_base & operator--(int){ // post decrement safe_base old_t = *this; --(*this); return old_t; } If I'm reading correctly, this is UB (and likely a segfault). > What is your evaluation of the documentation? The documentation is quite thorough. A "cheatsheet" page would be nice, because most of the documentation is rather in-depth. There are many bells and whistles documented that end users might not want to sift through. I'm not sure what this would look like, though. The FAQ appears to be formatted strangely. Notes about bitwise operators in the FAQ might be nice (signed right-shift especially). Very nice job overall. Much work and thought went into this. > What is your evaluation of the potential usefulness of the library? Useful. I'd consider using it in applications that are not latency-sensitive, perhaps if only in debug mode. Detecting accidental unsigned underflow is especially useful. I do think this library might be much more useful with floating point support, if it is eventually added. > Did you try to use the library? With what compiler? Did you have any problems? No. > How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? 3 hours reading documentation, source code, and previous reviews. > Are you knowledgeable about the problem domain? No more than any CS grad should be. > Do you think the library should be accepted as a Boost library? Yes. This library would be a good addition to Boost. I trust that Robert will address the issues raised in this review and others (especially Steven's) before this library would be shipped with a future Boost release, should it be accepted.

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[container] moving a pre-built vector into a flat_set
by Sam Kellett 12 Mar '17

12 Mar '17

a common problem i encounter is that i have two stage's w/r/t to a large collection of data: building and querying. vector is obviously the king of building. flat_set is the king of querying. so what i often tend to do is build up a very large vector, sort it then create a flat_set using the flat_set(ordered_unique_t) constructor. however this still copies the entire vector into the flat_set, right? what i would like to be able to do is move the vector straight into the flat_set, something like: std::vector<T> data; flat_set data_set1(std::move(data)) // move vector in and sort it // or: std::sort(data.begin(), data.end()); // sort vector flat_set data_set2(ordered_unique_t, std::move(data)) // and move it in is this doable (am i just being blind?) or is there plans/interest for this?

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[safe_numerics] review
by John McFarlane 12 Mar '17

12 Mar '17

I'm reviewing this library as someone who has tried to use it in the past, has made minor contributions to it and has a vested interest in improving numeric support for C++ developers. However, I have very little knowledge of the code and relatively little experience of Boost and the Boost community. I hope my comments are helpful nevertheless. tl;dr: make `safe<>` more like the type I describe in [ http://wg21.link/p0554#componentization-safety] or at least ensure that the API can evolve toward this without backward-breaking changes. ---- I do feel that a safe integer type should be available to as many people as possible and Robert's approach is on the right track. But given the choice, I would make some significant API changes. Any of these which can be added incrementally should not delay acceptance of safe_numerics into Boost. The goal of making `safe<int>` a drop-in replacement for int is essential. But further, `safe<Rep>` should be a drop-in replacement for `Rep` where `Rep` is any integer type which exhibits "surprising" results, e.g. through UB of overflow / divide-by-zero or indeterminate initial value. `Rep` should not just be any type for which `std::is_integral_v<Rep>` is true and ideally, `safe<safe<Rep>>`, while pointless, should compile and function like `safe<Rep>`. Unfortunately, `safe<int>` fails to be a drop-in replacement for fundamental integer types for a number of reasons. Firstly, conversion from floating-point types is not fully supported [ https://github.com/robertramey/safe_numerics/issues/13] This alludes to a wider issue with the API of this library: it tries to do too much. Conversion from integers to real numbers is not so much *unsafe* as *lossy*. Users intuitively understand that `int n = 0.5;` will not define a variable with value 0.5 and this is often exactly what they intend, e.g.: void sample(map<safe<int>, safe<int>>& histogram, double v) { ++ histogram[v]; } If implicit conversions to and from other numeric types is not supported, this prevents potential users from converting existing programs. Bear in mind that implicit conversions do not prevent `safe<>` from catching run-time errors. And if one wishes to catch risky narrowing conversions, they already have tools to do this, e.g. GCC's `-Wconversion`. In short, it's a separate concern. Another example of overreach of the API is in governing the results of arithmetic operations. Via policy choice, `safe<int>` can produce auto-widening functionality, e.g. returning a 16-bit result from a multiply operation with 8-bit operands. This behavior belongs in a whole different class. It achieves overlapping safety wins but it complicates the interface. I believe that the correct approach is to produce a type which is dedicated to performing run-time overflow checks and another type which performs automatic widening and to combine them, e.g.: // simplified for clarity, see: wg21.link/p0554#composition-safe_elastic_integer template<typename Rep> class auto_widening_integer; template<typename Rep> class safe_integer; template<typename Rep> using extra_safe_integer = safe_integer<auto_widening_integer<Rep>>; Of the two component classes, `auto_widening_integer` can be used to perform limited overflow-avoidance with zero run-time overhead. (The penalty is that if, say, you multiply two 32-bit integers together, you get back a 64-bit result.) Meanwhile, `safe_integer` provides iron-clad run-time safety checking and obeys the promotion rules of its `Rep` type. The combination of them reduces the number of run-time checks by reducing the chance of overflow. This solution is more complex, but the individual components are simpler and self-sufficient. Unfortunately, due to these kinds of design choices, I have not spent more time attempting to integrate Robert's library with my own. I would dearly like to include `safe<>` as part of a wider set of numeric components which users can then combine to their hearts content. Details of how I think that might come about can be found in (shamelessly plugged) paper, [wg21.link/p0554]. I accept that's a tall order. At the very least I would like developers of substantial projects to be able to replace build-in integers with the following: #if defined(NDEBUG) template<typename Rep> using Integer = Rep; #else template<typename Rep> using Integer = safe<Rep>; #endif Hope that helps, John

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HELP Needed
by Poulomi Hore 11 Mar '17

11 Mar '17

Hi, I would like to work on project 1 under Boost.Geometry for GSoc 2017. Can you please suggest as to where should i start from ? Thank you. Regards, Poulomi Hore

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[safe_numerics] One more review
by Antony Polukhin 11 Mar '17

11 Mar '17

- What is your evaluation of the design? Looks good, simple to use. I'd like to see an additional statefull ExceptionPolicy that remembers that an UB was triggered, but does not throw at all. Here's how it could be used: bool try_do_something(int& out) noexcept { using namespace boost::numeric; safe<int, native, lazy> x = INT_MAX; // remembers that error was triggered ++x; // ... other operations on `x` // ... if (!x.no_errors()) { // One of the operations triggered UB return false; } out = x; return true; } - What is your evaluation of the implementation? Checked a few border cases that I'm aware of. All of them were taken care of in the library. Nitpicks: Missing BOOST_NORETURN in multiple places, for example https://github.com/robertramey/safe_numerics/blob/master/include/exception_… . Adding that attribute may result in better code generation and in warnings suppression. std::is_literal_type type trait is deprecated since C++17 https://github.com/robertramey/safe_numerics/blob/master/include/interval.h… More generic streaming operators could be profitable (better to use basic_ostream<Char, Trait> instead of ostream) https://github.com/robertramey/safe_numerics/blob/master/include/interval.h… Many operations may be decorated with noexcept This macro seems broken https://github.com/robertramey/safe_numerics/blob/master/include/safe_liter… . Also looks like this class is not covered well with tests, because line https://github.com/robertramey/safe_numerics/blob/master/include/safe_liter… shall not compile There's a bunch of implicit conversions in the library https://github.com/robertramey/safe_numerics/blob/master/include/safe_base.… (BTW, have not found a body of this one). Would it be better to make them explicit? Those headers are very heavy https://github.com/robertramey/safe_numerics/blob/7ee656ecdf23f6f29f9333176… Try using <iosfwd> and making all the function below to use `basic_ostream<Char, Trait>&`. No need to define those in `namespace std` https://github.com/robertramey/safe_numerics/blob/7ee656ecdf23f6f29f9333176… . Defining those in `boost::numeric` namespace works fine (thanks to ADL!). I'd really like to see tests coverage for the library. This is pretty simple to add, just follow the instructions from here: https://svn.boost.org/trac/boost/wiki/TravisCoverals - What is your evaluation of the documentation? Good, very interesting examples. - What is your evaluation of the potential usefulness of the library? Useful. I was dealing with such problems in Boost.LexicalCast. - Did you try to use the library? With what compiler? Did you have any problems? Have not tried. - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? About two hours of reading source code and docs. - Are you knowledgeable about the problem domain? A little bit, not an expert. - Do you think the library should be accepted as a Boost library? Yes, the library should be accepted. -- Best regards, Antony Polukhin

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[safe_numerics] Formal review starts today
by Andrzej Krzemienski 11 Mar '17

11 Mar '17

Hi Everyone, Today, on March 2nd (or tomorrow, depending on your timezone), is the start of the formal review of safe_numerics library by Robert Ramey. The review will run till March 11th. I will be serving as review manager. safe_numerics is a set of drop-in replacements for the built-in integer types, which make the guarantee that the results of operations are either correct according to the rules of integer arithmetic or report a diagnosable error (rather than offering modulo arithmetic results, or resulting in undefined behavior, or returning incorrect results as in the case of signed vs. unsigned comparisons). The library can be found on GitHub: https://github.com/robertramey/safe_numerics/ Online docs: http://htmlpreview.github.io/?https://github.com/robertramey/safe_numerics/ master/doc/html/index.html Formal Review comments can be posted publicly on the mailing list or Boost Library Incubator <http://blincubator.com>, or sent privately to the review manager, that is myself. Here are some questions you might want to answer in your review: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? 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? And most importantly: Do you think the library should be accepted as a Boost library? For more information about Boost Formal Review Process, see: http://www.boost.org/community/reviews.html Your review is needed! Regards, Andrzej Krzemieński, review manager.

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[safe_numerics] Last three days
by Andrzej Krzemienski 11 Mar '17

11 Mar '17

Hi Everyone, We have three last days remaining for safe_numerics review (till March 11th). If you like working under time pressure, this is the perfect moment for doing your review. If you would like to submit your review, but feel you will not make it till March 11th, let me know, we can try to extend the review period. Currently, I recorder three reviews with a yes/no call, from Paul A. Bristow and Steven Watanabe, and one without a yes/no call from Vicente J. Botet Escriba. If you have submitted a review, but were not mentioned in my list, please let me know: it means I must have missed it. ----- safe_numerics is a set of drop-in replacements for the built-in integer types, which make the guarantee that the results of operations are either correct according to the rules of integer arithmetic or report a diagnosable error (rather than offering modulo arithmetic results, or resulting in undefined behavior, or returning incorrect results as in the case of signed vs. unsigned comparisons). The library can be found on GitHub: https://github.com/robertramey/safe_numerics/ Online docs: http://htmlpreview.github.io/?https://github.com/robertramey /safe_numerics/master/doc/html/index.html Formal Review comments can be posted publicly on the mailing list or Boost Library Incubator <http://blincubator.com>, or sent privately to the review manager, that is myself. Here are some questions you might want to answer in your review: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? 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? And most importantly: Do you think the library should be accepted as a Boost library? For more information about Boost Formal Review Process, see: http://www.boost.org/community/reviews.html Regards, &rzej;

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how can I use ipv6 on boost::asio
by Kazuaki Okimoto 11 Mar '17

11 Mar '17

Hi I can connect through IPV4 when I open the socket by following method. _socket->open(boost::asio::ip::tcp::v4()); But , it can't use IPV6 network. I'd like to use my app on IPV6 network. How can I use IPV6 on boost:asio ? Dies anyone tell me the method of it ? best regards

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IPC: compiler optimization related issues
by Robert 11 Mar '17

11 Mar '17

Hi! Before creating a bug in trac, would you accept issues related to compiler optimization (-O2 and -O3) flags? I have a very specific issue with an inter-process mutex (race condition), but it can be reproduced only when flag O2 or higher is being used during compilation. Thank you!

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To contribute in Static map (boost::static_map<Key, T, ConstExprHash = boost::constexpr_hash<Key>, Pred = boost::constexpr_equal_to<Key>>)
by SUSHIL KHANCHI 11 Mar '17

11 Mar '17

Hello, I am an engineering student in Computer Science from SMVDU(India). I would like to contribute to your STATIC MAP project and take part in Gsoc.For getting familiar to your work, I would like to get my hands on your projects issues. Can you please guide me to your project where I can start with fixing small bugs.

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[Endian] Reading/writing from/to byte buffers
by Olaf van der Spek 10 Mar '17

10 Mar '17

Hi, One often needs to read or write values from/to a buffer while having a pointer. Could you support this? I guess one could use *reinterpret_cast<big_int64_buf_t&>(*p) but I think functions would be more convenient. On second guess one probably has to use memcpy rather then reinterpret_cast. The functions are probably implemented already but aren't exposed. https://github.com/boostorg/endian/issues/17 -- Olaf

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Fw: Build failed: smart_ptr 1.0.81-develop
by Peter Dimov 10 Mar '17

10 Mar '17

AppVeyor says that bootstrap.bat is broken: bootstrap Building Boost.Build engine ****** B A T C H R E C U R S I O N exceeds STACK limits ****** Recursion Count=509, Stack Usage=90 percent ****** B A T C H PROCESSING IS A B O R T E D ****** Command exited with code 255 -----Original Message----- From: AppVeyor Sent: Friday, March 10, 2017 17:22 To: pdimov(a)pdimov.com Subject: Build failed: smart_ptr 1.0.81-develop Build smart_ptr 1.0.81-develop failed Commit fac6fbe3cf by Glen Fernandes on 3/10/2017 3:21 PM: Update documentation in make_shared_array.html Configure your notification preferences

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[regression dashboard] missing tests
by Raffi Enficiaud 10 Mar '17

10 Mar '17

Hi all, The regression dashboard is truncated, I should see many more tests here: http://www.boost.org/development/tests/develop/developer/test.html at least as many as for the master branch: http://www.boost.org/development/tests/master/developer/test.html Any idea? Raffi

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[stacktrace] review
by Artyom Beilis 10 Mar '17

10 Mar '17

Hello, This is my review of stacktrace library: Note that I have experience with the subject as I developed a similar library for the CppCMS framework [1] > - What is your evaluation of the design? > The design is straight forward and I don't see any major issues with the API. Also I have several suggestions in handling backtrace with catch from } catch (const traced& e) { std::cerr << e.what() << '\n'; if (e.trace) { std::cerr << "Backtrace:\n" << e.trace << '\n'; } } catch (const std::exception& e) { std::cerr << e.what() << '\n'; } In my library I use much simpler approach in terms of API [2] catch(std::exception const &e) { std::cerr << e.what() << std::endl; std::cerr << booster::trace(e); } Where booster::trace is a manipulator that prints strack trace if "e" contains backtrace information - much shorted code without additional catch. I find it very easy to use. Just a suggestion. I also like with_trace templated class idea. > - What is your evaluation of the implementation? Most of my > personal concerns with this library are with the implementation and I > would hugely appreciate feedback from others with substantial > experience of using stacktracing "in anger" in non-trivial use case > scenarios. I mostly reviewed the backend. Linux: ========= 1st of all: I recommend mentioning in the documentation the option -rdynamic/-export-dynamic as otherwise dladdr would likely to fail - it is critical as many may miss one. Regarding use of add2line utility: 1. Failing to calling an external program in case of dladdr fails is bad idea. This behaviour is unexpected by the user. I understand the advantage of this as you can use debug information but should be done only per user specific request (i.e. compilation option) and not by default. 2. If you call add2line - use it for ALL addresses in backtrace at once and not for each single one! My recommendation is to provide alternative backed that uses other way to extract information not involving forking. Maybe try to analyze debug data or so - or require preparing initial map using nm tool and than loading it from file or something like that. Additionally calling the backed linux is bad - as same approach with slight modifications works on *BSD, Mac OS X and Solaris (RIP). Windows: ======== I have a question why you used COM instead of SymFromAddr functions? I understand thread safety issues but simple mutex can solve them. My concerns are regarding MinGW compilers. Have you tested it on MinGW compiler? It wouldn't work as it used MSVC debug information in general so maybe it is good idea to provide an alternative backend that extracts only address and DLL name so you can analyse the stacktrace later (using addr2line utility for example) Take a look on my code [1] regarding non-msvc windows compilers - it provides at least some useful information. > - What is your evaluation of the documentation? The documentation is ok in general and straight forward as the library itself. What I do lack is the documentation of underlying backends - how do they work. 1. use of -rdynamic/-export-dynamic should be noted in "bold face" regarding the use of the library. 2. please do not call it "POSIX backend" - as there none of the stuff you use is actually POSIX... Also you'll probably need different backends for MINGW and mention it. > - What is your evaluation of the potential usefulness of the > library? Very Very useful. > - Did you try to use the library? With what compiler? Did you have any problems? No I didn't - I mostly read the documentation and the backend code. > - How much effort did you put into your evaluation? A glance? A > quick reading? In-depth study? 3-4 hours > - Are you knowledgeable about the problem domain? Yes I am. I have written similar library for CppCMS project [1] - FINAL VOTE: Yes, Conditionally Conditions: Use of addr2line must not be enabled by default. [1] https://sourceforge.net/p/cppcms/code/HEAD/tree/framework/trunk/booster/boo… https://sourceforge.net/p/cppcms/code/HEAD/tree/framework/trunk/booster/lib… [2] https://sourceforge.net/p/cppcms/code/HEAD/tree/framework/trunk/booster/boo… Best Regards, Artyom Beilis

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boost::asio::ssl::stream handshake hang up in reconnection
by jupiter 09 Mar '17

09 Mar '17

Hi, I am running boost socket communication on Debian 8, the following client code works fine when it connected to the server the first time. s.lowest_layer().connect(*endpoint_iterator++, error); s.handshake(boost::asio::ssl::stream_base::client, error); But when the server connection lost, the client would try to run above code repeatedly until the server connection was resumed, the it passed the first line of s.lowest_layer().connect without error, but the it stuck at s.handshake(boost::asio::ssl::stream_base::client, error), the handshake hang up. What I could be missing here? Thank you.

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[preprocessing] Feedback requested on a C99 preprocessor written in pure universal Python
by Niall Douglas 09 Mar '17

09 Mar '17

Those of you who watch reddit/r/cpp will know I've been working for the past month on a pure Python implementation of a C99 conforming preprocessor. I am pleased to be able to ask for Boost feedback on a fairly high quality implementation: https://github.com/ned14/pcpp It passes the C11 standard's list of "tricky" preprocessor expansions and the mcpp test suite. It has no issue correctly handling the preprocessor metaprogramming I've thrown at it from my Boost libraries. I'm not going to claim it can handle Boost.Preprocessor or especially Boost.VMD and I've tried neither, but pull requests with source code fixes adding support for those (with accompanying unit tests) would be welcome. My main use case for writing this is to assemble my header only Boost libraries into a single "drop in and go" file. To that end it has a (still buggy) --passthru mode which passes through #define and #undef plus any #if logic which uses an undefined macro. I'm still working on pass through mode so expect showstopper bugs in that configuration, but as a straight highly standards conforming preprocessor it's ready for others to use and I welcome any feedback. There are a multitude of use cases, everything from running as a conforming preprocessor before invoking MSVC to compile right through to parsing, reflection and introspection of source code. (and yes it is also a Python library as well as a command line tool, you can find API reference docs at https://ned14.github.io/pcpp/) I look forward to any feedback and my thanks in advance for it. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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[regression runner] Preference libstdc++ vs. libc++
by Tom Kent 09 Mar '17

09 Mar '17

I have a bunch of linux regression runners that are executing clang runs of the boost regression suite (clang 3.0 - 4.0), currently these are all using the default, GCC libstdc++. Is there an interest from developers to see these runs with libc++? The basic options: 1) Convert all compatible clang builds to libc++, don't mess with libstdc++ & clang. 2) Duplicate all the clang builds to build each version with both (acknowledging that will add nearly 1/3 to the already large ~125 linux runs). 3) Change most of the runs, but keep a few token libstdc++ & clang runs, with the latest compiler version (what c++ standard c++14? c++1z?). 4) Just add a few token libc++ runs, with the latest compiler version (what c++ standard c++14? c++1z?). 5) Don't add libc++. For background (you can respond to one of the above preferences without reading on), there are two machines constantly running linux builds (in addition to the two windows ones) that I manage. One I consider the "full" suite of compilers. It runs clang 3.0 - 4.0 and gcc 4.4 - 6. For the oldest and latest releas (gcc 4.4, gcc 6, clang 3.0, clang 3.9), I run all the supported standard configs I could find (c++98, c++0x, gnu98, gnu0x -- c++03, c++11, c++14, c++1z and their gnu equivalents). I also do runs with optimization and warnings cranked, against the latest standard config e.g. "-std=c++1z -O2". For all the compiler versions that aren't on the endcaps, I just run a single config with whatever was the latest standard config for that compiler (e.g. gcc-4.8 with c++1y). This is all repeated for develop and master for a total of about 100 different configurations. The machine I consider the "fast results" machine is configured with only four runs, one each for the latest release of gcc and clang with the latest supported standard config (currently gcc-6 1z and clang-3.9 1z), for both master and develop. The goal here is that for any change checked in, the author will have feedback on its success against something modern and relevant within just a few hours. As a backup to the "fast results" machine, I also run those four regression modern runs, interspersed with the rest of the configs every dozen or so runs, bringing the total number of runs on the "full" machine up to around 125, which takes about a week for the machine to get through all the configurations. You can see more details about all of this on the github page where I keep my regression build scripts: https://github.com/teeks99/boost-build/tree/master/Regression The actual confgs run by the "full": https://github.com/teeks99/boost-build/blob/master/ Regression/teeks99-02/machine_vars.json The docker builds for all these machine configurations are kept at: https://github.com/teeks99/boost-build/tree/master/Docker And can be pulled from the docker hub with e.g. `docker pull teeks99/boost-build:clang-3.9` If you've read this far, I'd be happy for any other opinions from developers who use the test matrix. Is it worth keeping all those compilers in the middle? Do we need to test the latest compilers with all the different standard configs (03, 11, 14, 1z + gnu equivalents)? Thanks, Tom

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[safe numerics] comment
by Robert Ramey 09 Mar '17

09 Mar '17

I'm re-posting Vicente's message which apparently got lost in a server issue so we can respond to it. Robert Ramey Hi, let me start with some comments and questions. I was wondering if the requirements of Numeric don't need some kind of conversions between other numeric types. https://htmlpreview.github.io/?https://raw.githubusercontent.com/robertrame… T(u) T{u} How can you implement the conversion from safe<U> to T if you can not convert from U to T? We have implicit conversion from T to Safe and from Safe to T template<class T> constexpr /*explicit*/ safe_base(const T & t); template< class R, typename std::enable_if< !boost::numeric::is_safe<R>::value, int >::type = 0 > constexpr operator R () const; constexpr operator Stored () const; I believed that the conversion from Safe to T needed to be explicit. Having implicit conversion in both directions is suspect. Why the explicit conversion between safe<T> and safe<U> are not allowed when T and U are not the same? IMO, safe_base<T> is either not trivial default constructible and we check the validity of 0, if we don't check it, we should declare it =default. The current definition doesn't adds nothing and makes the type a non-POD and non trivial_default_constructible, which forbids its use on binary messages. constexpr explicit safe_base() { // this permits creating of invalid instances. This is inline // with C++ built-in but violates the premises of the whole library // choice are: // do nothing - violates premise of he library that all safe objects // are valid // initialize to valid value - violates C++ behavior of types. // add "initialized" flag. Preserves fixes the above, but doubles // "overhead" // still pending on this. } I'll suggest to use constexpr safe_base() = default; BTW, why the default constructor is declared explicit? As you say, could we talk of safe<short> when we can have one uninitialized? I believe this needs to appear clearly on the documentation if not already in. Has safe<const T> a sense? Integer<T> are not traits as there is a compiler error when T is not an integer :( template <class T> class Integer : public Numeric<T> { // integer types must have the corresponding numeric trait. static_assert( std::numeric_limits<T>::is_integer, "Fails to fulfill requirements for an integer type" ); }; The same for Numeric. Have you considered to define traits (usable with SFINAE)? I don't see a concept SafeNumeric. Have you considerd it? BTW, these concept classes check only for a single requirement. Shouldn't you specialize numeric_limits lowest()? Have you considered to define basic algorithms managing with the valid conversion between Numeric with the different policies, as Lawrence Crowl is proposing for the standard? http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0103r1.html http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0105r1.html I find weird the way you are including the files #include "concept/integer.hpp" #include "concept/exception_policy.hpp" #include "concept/promotion_policy.hpp" #include "safe_common.hpp" #include "exception_policies.hpp" #include "boost/concept/assert.hpp" I believed we used to inlcude boost files using <> and the absolute path. Is this a good practice? Does it allows the compiler to perform better? Best, Vicente

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Regarding Mentor
by Shaunak Dixit 08 Mar '17

08 Mar '17

Hi I have joined the Boost Developer's mailing list please help me how to find a mentor. thanks you

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