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Using Boost.Random with fixed-point numbers
by John W 03 Oct '20

03 Oct '20

I have a fixed-point number class (based on libfixmath) which in code largely behaves like a float due to various operator overloading. Now, I am trying to generate random numbers with them. Uniform random is easy enough — just reinterpret some random bits as my fixedpoint type. However, I'd like to have other distributions, like boost::random::normal_distribution. But from what I can tell, Boost.Random might have some baked-in assumptions about only working on float/double/long double. Is that correct? Or are there ways I can more-or-less transparently use boost::random::xxx distributions with my custom type? Basically, I want to know how much the <RealType> template argument can be abused. In std::random, there is some clear language[1], saying: "The result type generated by the generator. The effect is undefined if this is not one of float, double, or long double." and I believe boost::random aims to be in agreement with std::random, generally. But I could not find such clear language in the Boost.Random docs. Thanks -John [1] https://en.cppreference.com/w/cpp/numeric/random/uniform_real_distribution

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[Boost.Compute]: double3 - typedef redefinition with different types
by Manfred Doudar 30 Sep '20

30 Sep '20

Hello List, [Posting over from the Slack channel which didn't get any attention]: Any Boost.Compute users here that might be able to help with the following code snippet - BOOST_COMPUTE_ADAPT_STRUCT(double3, double3, (x, y, z)) BOOST_COMPUTE_FUNCTION(bool, CompareX, (double3 a, double3 b), { return a.x < b.x; }); boost::compute::vector<double> points; ... auto it = boost::compute::min_element(points.begin(), points.end(), CompareX, queue); results in the kernel compilation failure - --- build log --- <kernel>:9:3: error: typedef redefinition with different types ('struct double3' vs 'double __attribute__((ext_vector_type(3)))') } double3; ^ cl_kernel.h:154:1: note: previous definition is here __NV_DECLARE_VECT_TYPES(double, double) ^ cl_kernel.h:114:61: note: expanded from macro '__NV_DECLARE_VECT_TYPES' typedef __attribute__(( ext_vector_type(3) )) CTYPE CLTYPE##3; \ ^ <scratch space>:53:1: note: expanded from here double3 ^ ^@ Thanks, /M

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unable to update boost version
by Shiladitya Porey 24 Sep '20

24 Sep '20

Respected Sir/Madam, I am running a code where the minimum required version of the boost package is 66. But the version of boost in my laptop is 65. I tried the command > sudo apt install libboost-filesystem-dev libboost-log-dev But it failed to update. Then I tried to download the package from the website and followed the instructions to install it. But still the version is still 65. Could you kindly help me, please? Thanking you, Sincerely, Shiladitya Porey -- Shiladitya Porey Graduate student Laboratory of Cosmology and Elementary Particle Physics <http://astro.nsu.ru/> Novosibirsk State University <https://english.nsu.ru/>, Russia Office: Room no. : 434,Old Building Mobile: 8 913 462-44-32 https://sites.google.com/a/g.nsu.ru/shiladitya/home

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[log]: Filter declaration in settings files, associativity and operator precedence
by Bill Somerville 18 Sep '20

18 Sep '20

Hi all, I am experimenting with using multiple channels with Boost.Log. I am using the boost::trivial severity levels, the common attributes, and logging using BOOST_LOG_SEV() using a mix of global and class specific loggers. I am also using boost::log::init_from_stream(std::istream&) to configure sinks from a settings file. I would like to be able to define a sink filter that allows increasing the logging verbosity on just one channel but I am struggling to write succinct filer expressions. E.g given three channels A, B, and C I would like to write: Filter="(%Channel% = \"B\" and %Severity% >= trace) or %Severity% >= warning" to increase the verbosity to trace only on channel B, but this doesn't work. I am finding I have to write: Filter="(%Channel% = \"B\" and %Severity% >= trace) or (%Channel% != \"B\" and %Severity% >= warning)" Is this expected behaviour? If so then declaring more complex filtering will become burdensome. Regards Bill Somerville.

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[Urgent request] : Boost default_locale() is causing an application crash!
by kamallochan Jena 17 Sep '20

17 Sep '20

Hi All, Thank you for your kind support! In one of our applications, we are using Boost library and recently found an application crash because of the locale object return from below highlighted code from Boost source code (path.cpp). Boost library source code (File name: path.cpp and line No: 865) seems to return NULL locale object [image: image.png] As per call stack, Application is found to be crashed when std::use_facet() tried to Getfacet id from the passed locale object : [image: image.png] Please Note: At above line 934, path_locale() calls to the above default_locale() which return an locale object with NULL value. *Can someone please answer the below queries:* 1>> In which scenario the code at std::locale(global_loc, new windows_file_codecvt);", mentioned above will return a locale object with NULL values ?? 2>> How to enable BOOST_ASSERT_MSG, so below code will execute ?? Example: BOOST_ASSERT_MSG(&path_locale(), "boost::filesystem::path locale initialization error"); 3>> In which conditions a locale object can be null ?? Thank you in Advance!!, please let me know if any further details are required on this issue. Regards, Kamal

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[multiprecision] 128 bit integer support on Windows
by Neill Clift 15 Sep '20

15 Sep '20

Hi, I managed to get boost multi-precision to work with 128 bit integers on Windows using clang. I had to change this in clang.hpp: #if defined(__SIZEOF_INT128__) && !defined(BOOST_NVCC_CXX03) && !defined(_MSC_VER) <--- remove this last thing # define BOOST_HAS_INT128 #endif Clang-cl defines _MSC_VER for compat I guess. I had to pull in the library clang_rt.builtins-x86_64.lib for two routines needed for division and remainder. For my particular application I only saw a 10% improvement in performance. I am wondering if there are other things that need to be changed to get better performance? My program deals with integers of various sizes so it might be an artifact of the sizes of integers I mostly do operations on. I was expecting a bigger return. I am seeing the most expensive routine being _udivmodti4 on profiling. Division wasn't showing up as much in the traces before I made the change. Thanks. Neill.

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Can boost.asio read/write io of files asynchronously?
by lampahome 02 Sep '20

02 Sep '20

As title, I read boost.asio documents and generally said io about http/network. I don't see any info. of io of files. Does boost.asio support read/write io of files asynchronously?

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Program-options and priority
by DV Henkel-Wallace 31 Aug '20

31 Aug '20

Hi. I'm finding program_options pretty handy but I have a usage question which is not clear from the documentation. Is a hierarchy of sources not possible if I use value<T>(&my_arg)? My use case is the following: I have a hierarchy of sources: command line, environment variables, user-specified config file or default config file, and lastly a system default. I just set my_arg to whatever default is appropriate and then let parse_command_line do all the work. This is convenient because I can have a module simply define an options_description for callers to use. This works fine unless the option is specified twice (say command line and then environment). The last of the two values is used rather than the first one. Is this hierarchy only possible if I use value<T>() and not value<T>(&my_var)? That will add some complexity for callers. Thanks, d

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Re: [Boost-users] Beast for IMAP
by Kenneth Porter 29 Aug '20

29 Aug '20

--On Saturday, August 29, 2020 11:27 AM +0300 Zhivko Vasilev via Boost-users <boost-users(a)lists.boost.org> wrote: > And IMAP complexity by itself is a "Beast" compared with SMTP. > > Not from boost libraries, but have you look at these libraries if you need > IMAP support. > https://github.com/dinhviethoa/libetpan > https://github.com/MailCore/mailcore2 > > As far as I know, most of the "modern" email apps which haven't used > proprietary code are based on these libraries. Thanks. I'd seen those and also this one: https://www.vmime.org/ I'm coming from using Mulberry and Thunderbird, which have their own IMAP implementation, but neither of those look easy to extract as standalone libraries. In addition to the complexity of IMAP, there's the need for authentication and encryption support, so there's a stack of additional libraries like GnuTLS, cyrus-sasl, and openssl needed. Some of these are hard to build on Windows. Fortunately the new Windows Linux Subsystem allows one to run Linux-based GUI programs in a VM and display on the Windows desktop. So I may go that route.

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Beast for IMAP
by Kenneth Porter 29 Aug '20

29 Aug '20

I've been thinking about writing some email utilities and have looked at various IMAP libraries. I'm wondering if I should roll my own using Beast. I've seen an SMTP library using Beast on GitHub. Has anyone else attempted an IMAP client with Beast?

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Re: [Boost-users] Beast for IMAP
by Richard Hodges 29 Aug '20

29 Aug '20

I maintain boost.beast. If you need any guidance or help you can find me on the cpplang slack most days in the #beast channel. https://cppalliance.org/slack/ On Sat, 29 Aug 2020 at 01:48, Kenneth Porter via Boost-users < boost-users(a)lists.boost.org> wrote: > I've been thinking about writing some email utilities and have looked at > various IMAP libraries. I'm wondering if I should roll my own using Beast. > I've seen an SMTP library using Beast on GitHub. Has anyone else attempted > an IMAP client with Beast? > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > https://lists.boost.org/mailman/listinfo.cgi/boost-users > -- Richard Hodges hodges.r(a)gmail.com office: +442032898513 home: +376841522 mobile: +376380212

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Re: [Boost-users] Beast for IMAP
by Zhivko Vasilev 29 Aug '20

29 Aug '20

SMTP build with HTTP library sounds very strange. Beast is an HTTP 1.1 protocol library. IMAP and SMTP are also protocols and have nothing related to their syntax with HTTP. I had worked on the IMAP/SMTP app, and I think it is better to build with Asio only. The only one related point between HTTP and IMAP/SMTP, is if you need OAuth auth integration. Regards, Zhivko On Sat, Aug 29, 2020 at 2:48 AM Kenneth Porter via Boost-users < boost-users(a)lists.boost.org> wrote: > I've been thinking about writing some email utilities and have looked at > various IMAP libraries. I'm wondering if I should roll my own using Beast. > I've seen an SMTP library using Beast on GitHub. Has anyone else attempted > an IMAP client with Beast? > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > https://lists.boost.org/mailman/listinfo.cgi/boost-users >

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[LEAF] Review Results
by Michael Caisse 28 Aug '20

28 Aug '20

I want to thank Emil for his patience for the publishing of the review results as life got in my way. Thank you Emil for submitting LEAF to be reviewed for inclusion into Boost. As an already-Boost-author, you knew what you were getting into and continued into the process. I also want to thank you for once again pushing our thoughts on error handling. -------- Result -------- This is the part everybody scrolls to the bottom to read, so let’s just put it at the top. Boost.LEAF is ACCEPTED into Boost. After the following modifications are made to the library, the repository can be transitioned to Boost for inclusion into the next release (with the release cycle timing constraints): Specify the TLS requirement sooner in the documentation. Optional usage of Boost.Config to perform all of the Boost Configy things. (further discussion on this below) Macro naming and general Boostification clean-up. -------- Reviews -------- There was a good amount of discussion about the library on both the dev and user mail lists. I want to personally thank those who got involved in the review. You make the process work! Result summary: Accept: 7 Reject: 1 No-decision: 3 The no-decision reviews provided valuable input and discussion threads. While it would be my preference to have the review authors provide a final verdict, I was grateful for the time and energy they spent with the library and formulating thoughts into emails for discussion. Some comments from reviews: “I find function preload() really great and novel. … This really makes the error reporting code brief, clean and bug-free.” “I like LEAF very much and there's a lot offered here…” “I like it.” “...it allows bridging multiple error handling strategies and usage patterns in an efficient way.” About the docs: “They look good and manage to explain hard concepts in a very approachable fashion.” “The documentation is great -- in terms of styles it's probably the best I've seen for a C++ library.” “Clear, friendly and complete.” -------------- Some Thoughts -------------- While there was overwhelming consensus that LEAF should be included into Boost, the process is not democratic. I have spent considerable time understanding the concerns raised in each of the reviews and in particular the singular rejection. Emil took time responding to each of the reviews. The exchanges were fruitful and both “conditional accept” and “reject” reviewers changed their verdicts to accept along the way. Most of the concerns were amicably resolved. I am comfortable with the design choices and implementation made by the author for the remaining items. One reviewer brought up the re-implementation of Boost.Config type facilities. This of course is a complex issue for a library with zero dependencies. The ability to simply drop the Boost.LEAF directory into a project and run is a definite plus for a specific user segment. Being able to modify a single Boost.Config repository to support WackyCompiler14 targeting LEG Core and get a bunch of libraries for the ride is also a plus. Emil and I have discussed these concerns and the best choice seems to be defaulting to zero dependencies and the option to pull in Boost.Config to provide configuration type facilities if needed. Accepting a library into Boost is as much about the library as it is bringing the author into a group. While Emil is already part of the author crowd, it was clear to me through his careful, informative, and patient responses that the addition of Boost.LEAF brings professional maturity that strengthens the community. A user with more than a year of experience with the library voted acceptance based on the “qualities of the library itself and the responsiveness and openness for feedback of its author.” Throughout the review period, Emil integrated feedback to both the documentation and code in another branch. It was wonderful to see the community provide input and the author respond so quickly to produce a better final result. Thank you Emil for your vision of better error handling and striving to bring us along! -- Michael Caisse Ciere Consulting ciere.com

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[Lockfree] spsc example query
by Sean Farrow 25 Aug '20

25 Aug '20

Hi, I'm just about to start using the spsc queue in a project and whilst reading the example at: https://www.boost.org/doc/libs/1_74_0/doc/html/lockfree/examples.html#lockf… looking at the consumer function, there appears to be two while loops retrieving items from the queue inside the outer loop that checks whether the done variable is true. Can somebody please explain why this is, or, is it a bug in the example? I would have thought one inner while loop would be enough. Thanks, Sean.

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JSON library scheduled for review
by Mateusz Loskot 25 Aug '20

25 Aug '20

Hi, A brief announcement from the review wizards: Formal review of the JSON library has been scheduled to take place between October 9 and October 18, 2020. Details and links available here https://www.boost.org/community/review_schedule.html We'd like to thank Pranam Lashkari (Boost.GIL, [Boost.]Astronomy, Boost GSoC) for volunteering to act as the review manager. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[Log] Formatting multiple attributes in a single formatter
by Michael Jones 24 Aug '20

24 Aug '20

TL;DR; I'm looking for help/advice/code on creating a custom formatter, or formatter factory, to format more than one attribute at a time into a single "placeholder" in the format expression. I do not yet have code, working or otherwise, to try to solve this, because I am still trying to understand the design space of Boost.Log's API. I have been using Boost.Log successfully in my project for about 1-2 years now, with many hundreds of log statements of the style MY_LOG_MACRO(Normal) << "My Log Message" << std::endl << "- Attribute 1:" << myAttributeVar1 << std::endl << "- Attribute 2:" << myAttributeVar2; I now want to convert these hand-formatted attributes that are directly inserted into the message into attributes in the Boost.Log meaning. However, these attributes are "free form", in the sense that they are not pre-registered with Boost.Log before use (which is obvious given they are manually formatted into the message string), and they do not conform to any specific naming conventions or value-type scheme. I estimate that there are a few hundred different attributes that are printed to my logs in various places as "one off" attributes that are not really meaningful outside of the specific log statement they are used in. My current plan is to provide my developers with a way to incrementally move their logging toward using Boost.Log's attributes without requiring a flag-day where every log statement is changed in a single merge. I want to do this by allowing these attributes to be added to the log message using boost::log::add_value() from boost/log/utility/manipulators/add_value.hpp, such as: MY_LOG_MACRO(Normal) << "My Log Message" << boost::log::add_value("Attribute 1", myAttributeVar1) << boost::log::add_value("Attribute 2", myAttributeVar2); However, I want to provide the same formatting semantics that they are used to, to make the transition easier. At this stage, it is not clear whether I'll ever be able to get a set of standardized attributes that can be pre-registered with the Boost.Log library. A surface level estimate shows me that I have, at the minimum, many dozens of different attributes with unique names / value-types. This would make addressing each such attribute name individually prohibitively expensive to add to the format expression Currently, using boost::log::import_from_stream(), I use a format expression like: Format="%Process%/%Channel% - [%Severity%] %Message%" And I would like to change that to the following, or something similar: Format="%Process%/%Channel% - [%Severity%] %Message%\n%Attributes%" The intention of %Attributes% here would be a placeholder in the format expression that gets resolved to a custom formatter, or formatter factory, which will iterate through the list of attributes in the current record_view and print each attribute name and value with a new line separator. Ideally, this formatter or format factory would be able to recognize that a particular attribute has already been printed, or will be printed, so that it only adds new information to the log. However, I believe this is not something that can be easily done, so I currently plan to have this duplicated information in the log with the intention to resolve it another time. One way I could resolve the duplicate information problem is by adding an option block to the %Attribute% placeholder, e.g. %Attribute[Exclude:Process, Exclude:Channel, Exclude:Severity, Exclude:Message]%. It would be ugly, but it would do the job. So far I've gathered the following information about this subject: How the default formatter factory works by creating a default_formatter, which has special handling for various time types, but otherwise just calls operator<<(stream_type, value); https://github.com/boostorg/log/blob/develop/src/setup/default_formatter_fa… How the format parser works by, well, parsing the format expression to get attribute names and other important information for later use. I don't have a complete understanding of this, but I get the gist of it. https://github.com/boostorg/log/blob/develop/src/format_parser.cpp How sinks_repository from init_from_settings.cpp works by pre-defining multiple different sink-factories with the repository, and then init_from_settings() uses those pre-defined factories to support loading the settings. Notably, I use default_text_file_sink_factory, and default_console_sink_factory in my own code. Both of those sink factories just use boost::log::parse_formatter() to create the formatter from the format string in the settings file. https://github.com/boostorg/log/blob/develop/src/setup/init_from_settings.c… How formatter_repository and works by storing a map between the Attribute name and the Formatter Factory to use. https://github.com/boostorg/log/blob/develop/src/setup/formatter_parser.cpp Record_view, it's read-only nature, and how to access the attributes for the record using the boost::log::record_view::attribute_values() function. https://github.com/boostorg/log/blob/develop/include/boost/log/core/record_… The next thing I am going to try is to define a custom formatter for the %Attributes% attribute name, and pre-define some constant value for it so that it is always defined for each record. Then I'll have a formatter factory like this (psuedo code, not compile tested) template< typename char_type > struct abitrary_attribute_formatter { void operator() ( boost::log::record_view const& rec, boost::log::basic_formatting_ostream< char_type >& strm ) const { for(auto const& attr : rec.attribute_values()) { strm << "- " << attr.name() << ": " << attr.value(); } } }; What I'm currently trying to understand is how I can create a custom formatter that dispatches to other formatters. How is this done? Is there a more straight-forward way to accomplish the goal of providing a formatter for the concept of "All available attributes"? If not, can anyone offer implementation or design advice?

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[Boost.Accumulator] retrieve percentage corresponding to a value
by Timo Sachsenberg 24 Aug '20

24 Aug '20

Hi, Boost offers convenient methods in the accumulator library to get e.g. a value (let's say 1234) corresponding to a certain quantile (let's say 0.995). For my specific use-case I wonder if the opposite (value input=1234, output=0.995) is also possible. Is there an elegant way to calculate/estimate the percentile of value in an online fashion (=while accumulating) and without storing all values? One thing I came up with is using extended_p_square_quantile with many probabilities and then do a binary search over the values output by the quantile() function. Is there an easier way to directly get the percentile from the value that I am missing? Best, Timo

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limited accuracy for tanh-sinh integrator
by Anirban Pal 23 Aug '20

23 Aug '20

Hello, I’m using the tanh-sinh integrator to integrate a simple function f(x) = 0.26*x from 3.0 to 4.0. The exact result is 0.91. With the integrator I’m getting a result accurate to only 10^-18 with cpp_bin_float_100 multiprecision. typedef boost::multiprecision::cpp_bin_float_100 Real; int main(int argc, char **argv) { using namespace boost::math::quadrature; using namespace std::placeholders; tanh_sinh<Real> integrator; auto f2 = [](Real x) { Real a = 0.26; return x*a; }; std::cout << std::setprecision(std::numeric_limits<Real>::max_digits10) << "Comp.: " << integrator.integrate(f2, (Real) 3.0, (Real) 4.0) << std::endl; return 0; } I'm getting an output of Comp.: 0.9100000000000000310862446895043831318616867065429687499999999999999999999999999999999999999999999999429 which I'm a bit curious about. I was wondering if I can improve the result. Thank you. -- Anirban Pal

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[Beast] streaming a large compressed file
by Sean Farrow 22 Aug '20

22 Aug '20

Hi, I'm trying to download a compressed .7z file with boost.beast. The file is about 9GB in size, so what I'd like to do is stream the response in to boost.iostreams to allow decompression. Is there any examples of interfacing boost.beast with boost.iostreams in this sort of streaming context? Any help appreciated. Thanks, Sean.

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Integrate function with arguments using quadrature
by Anirban Pal 21 Aug '20

21 Aug '20

Hello, I'm trying to integrate functions with BOOST quadrature routines. So far they have been extremely impressive accuracy-wise, particularly with multiprecision features. I wish to integrate a function and pass some arguments to it. These arguments can be scalars, matrices, structs or objects. I was wondering if there is an example that explores this. Would I need to use a boost.function? Or would a function pointer work? I currently have an implementation using GSL_functions which explicitly allow the function and parameters to be passed as pointers. I am curious if I can do something similar with boost. Thank you. -- Anirban Pal

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PFR (Precise and Flat Reflection) by Antony Polukhin scheduled for review
by Mateusz Loskot 18 Aug '20

18 Aug '20

Hi, A brief announcement from the review wizards: Formal review of Antony's library has been scheduled to take place between September 28 and October 7, 2020. Details and links available here https://www.boost.org/community/review_schedule.html Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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help with serialization error
by Lorenzo L 14 Aug '20

14 Aug '20

I'm trying to compile a piece of software called Bagel (a quantum chemistry program) written in C++ and which uses Boost. I get a compilation error, and as I don't know C++ and I've never used boost I'm essentially lost. The author of the program says the problem I'm experiences depends on my boost installation and not on the program itself. I installed boost 1.73.0 (Linux Mint 20, g++ 9.3.0) doing: sudo ./bootstrap.sh --prefix=/usr/local sudo ./b2 install When compiling the program I get the following error: /usr/local/include/boost/serialization/access.hpp:119:11: error: 'class std::unordered_set' has no member named 'serialize' 119 | t.serialize(ar, file_version); | ~~^~~~~~~~~ /usr/local/include/boost/serialization/access.hpp: In instantiation of 'static void boost::serialization::access::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive; T = std::unordered_set]': /usr/local/include/boost/serialization/serialization.hpp:69:22: required from 'void boost::serialization::serialize(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive; T = std::unordered_set]' /usr/local/include/boost/serialization/serialization.hpp:128:18: required from 'void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::binary_oarchive; T = std::unordered_set]' /usr/local/include/boost/archive/detail/oserializer.hpp:148:40: required from 'void boost::archive::detail::oserializer::save_object_data(boost::archive::detail::basic_oarchive&, const void*) const [with Archive = boost::archive::binary_oarchive; T = std::unordered_set]' /usr/local/include/boost/archive/detail/oserializer.hpp:101:1: required from 'class boost::archive::detail::oserializer' /usr/local/include/boost/archive/detail/oserializer.hpp:253:13: required from 'static void boost::archive::detail::save_non_pointer_type::save_standard::invoke(Archive&, const T&) [with T = std::unordered_set; Archive = boost::archive::binary_oarchive]' /usr/local/include/boost/archive/detail/oserializer.hpp:308:22: [ skipping 21 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ] ... The following post https://lists.boost.org/boost-users//2014/03/81583.php [1] report on a similar error, but I couldn't understand what I should to solve it. Any advice would be appreciated! Con Tiscali Mobile Smart 30 4G hai minuti illimitati, 100 SMS e 30 Giga in 4G a soli 8,99€ al mese. http://tisca.li/smart30

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[release] Boost 1.74.0
by Marshall Clow 14 Aug '20

14 Aug '20

Release 1.74.0 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 1 new library and numerous enhancements and bug fixes for existing libraries. For details, including download links, see < http://www.boost.org/users/news/version_1.74.0> You can also download directly from: < https://dl.bintray.com/boostorg/release/1.74.0/> 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

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Difficulty using boost quadrature library
by Anirban Pal 14 Aug '20

14 Aug '20

Hello everyone, I'm new to using boost and I'm trying to use its quadrature routines, specifically the *tanh_sinh* integrator. I'm trying to run the examples here: <goog_14736225> https://www.boost.org/doc/libs/1_66_0/libs/math/doc/html/math_toolkit/doubl… I've been successful using it with the *double* datatype. However, I can't seem to work with the *Real* datatype. When I run the following, I'm successful. tanh_sinh<double> integrator;auto f = [](double x) { return 5*x + 7; };double Q = integrator.integrate(f);Q = integrator.integrate(f, 0.0, 1.1); But when I run the following: auto f = [](Real x) { return log(x)*log(1-x); };Real Q = integrator.integrate(f, (Real) 0, (Real) 1); I get the error: boost_test.cxx: In function ‘int main(int, char**)’: boost_test.cxx:47:15: error: ‘Real’ has not been declared auto f2 = [](Real x) { return log(x)*log(1-x); }; ^~~~ boost_test.cxx:48:2: error: ‘Real’ was not declared in this scope Real Q2 = integrator.integrate(f2, (Real) 0, (Real) 1); I think I need to include the right headers for this to go away. However, I'm not sure what the correct header file is. Thank you for your attention. -- Anirban Pal

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Building Boost With clang-cl.exe?
by Osman Zakir 12 Aug '20

12 Aug '20

I tried to build Boost version 1.73.0 with clang-cl.exe but ran into trouble. I've attached my project-config.jam file to this message for you guys to review, as well as the config.log file which shows the output for the run. The command I ran on the command line when invoking b2 was "b2 --build-type=complete address-model=64 install" But I saw in the output that the address model and architecture wasn't set and it seemed to think I was building for Linux. What went wrong?

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[release] Boost 1.74.0 Release Candidate 2
by Marshall Clow 12 Aug '20

12 Aug '20

The second release candidates for the 1.74.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.74.0/source/> The SHA256 checksums are as follows: 903fd40074de8dc733d2f0b6b0642e43b714653eaeb79289b12161b9567fae97 boost_1_74_0_rc2.7z 83bfc1507731a0906e387fc28b7ef5417d591429e51e788417fe9ff025e116b1 boost_1_74_0_rc2.tar.bz2 afff36d392885120bcac079148c177d1f6f7730ec3d47233aa51b0afa4db94a5 boost_1_74_0_rc2.tar.gz a0e7ce67c52d816708fdeccdd8c9725626ba61254c13c18770498cacd514710a boost_1_74_0_rc2.zip Changes from RC1: * Fix a recently introduced bug in Boost.Asio where it would read from uninitialized memory. 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

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[release] Boost 1.74.0 Release Candidate 1
by Marshall Clow 11 Aug '20

11 Aug '20

The first release candidates for the 1.74.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.74.0/source/> The SHA256 checksums are as follows: 9ea3fc8573413f4d4b2c4d448110b6cb0467df834304112e143c7edb09ae71e9 boost_1_74_0_rc1.7z 8b6c429a41f7cac1880594adf8d1d6f0cc1cf19f8980c6b86ac38ef8b3d8a4e0 boost_1_74_0_rc1.tar.bz2 a0a96a9bb3863863e034cafc825b2ddba4249c7d278b76df1277295e7c7afbf2 boost_1_74_0_rc1.tar.gz d4f31cce9d5fbd55691dc2f5fb73380e95aa66426c891ceb3ebdfc6616022842 boost_1_74_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

Boost-1.71.0 upgrade issue
by Tej Kumar 28 Jul '20

28 Jul '20

Hi Team, Hope you guys are doing well. I am trying to upgrade Boost to 1.71.0 version. My code is compiling and building successfully but during test run i see below error. Error seems to be related with boost chrono, even though i have included boost_chrono lib in my makefile. *undefined symbol: _ZN5boost6chrono12steady_clock3nowEv* It will be a great help if you guys can suggest something here. Thanks & Regards, Tej

2 3

[Graph] Unable to get the edge_color in depth_first_search
by Ashish Kumar 27 Jul '20

27 Jul '20

Hello, First of all, I am new to Boost Graph Library. So, there might be a simpler or easier fix to the problem I am facing. I am trying to get the edge color after executing the boost::depth_first_search algorithm on the graph. For that, I created an edge color map and passed it to the function. Also, to log the colors of the edges, I made a visitor class, passed the color of the edge to it, and printed it to the standard output stream, for the tree_edge, back_edge, etc. But, for every edge, the value of color comes out to be 0. So, I am not able to get the color of every edge. A small snippet of how I am calling the depth_first_search function: depth_first_search(graph, visitor(dfs_visitor(root, visited_order, colors, graph)) .edge_color_map(&colors) .root_vertex(root)); The complete code along with the visitor class can be found here: https://gist.github.com/krashish8/5f8d8e613e189857bd2b0fd46dd02b29 Please suggest any possible solution to this problem. Thank you, Ashish Kumar.

1 0

[boost] Clang on Windows - No Autolink?
by Klaim - Joël Lamotte 27 Jul '20

27 Jul '20

Hi, am I correct that autolinking is not supported by Boost when using Clang on Windows? To be clear, I'm talking about both clang++ and clang-cl drivers. The behavior I observe suggests that I am correct but looking at the autolink.hpp header I didn't understand how it decides if it should work or not. A. Joël Lamotte

3 8

Two Graphs Common Spanning Trees Issue [GSoC]
by Prakash Tiwari 24 Jul '20

24 Jul '20

Hello, Community Members and developers, I'm student of Google Summer Of Code and contributing to the pgRouting <https://github.com/pgRouting/pgrouting/>[1]. I need to use boost algorithm boost::two_graphs_common_spanning_trees. I have gone through the documentation and try to use it (with help of example.cpp) But I found that this algorithm is not returning the expected results. I have mentioned the example that I have used and explained the expected and given results <https://github.com/prakashupes/ProposalCodes/issues/1>.[2] So, please try to figure out that is it a bug implemented algorithm or It might be possible that I'm using the algorithm in the wrong way. Thanks Prakash Tiwari [1].https://github.com/pgRouting/pgrouting/ [2]. https://github.com/prakashupes/ProposalCodes/issues/1

1 0

jpeg resize - file size increases
by Lloyd 24 Jul '20

24 Jul '20

Hi, We tried boost gil resize example to experiment with scaling down a jpeg image file. For some images, this causes the size of the file to increase. We are using bilinear_sampler algorithm. Our aim to reduce the input image size so as to save storage/network bandwidth. Quality can be compromised to a certain extent. Which algorithm/method should we use? The code fragment is given below:- boost::gil::rgb8_image_t img; boost::gil::read_and_convert_image(InStream, img, T()); float width = (float)(img.width() * Ratio) / 100; float height = (float)(img.height() * Ratio) / 100; boost::gil::rgb8_image_t resizedImg(width, height); boost::gil::resize_view(const_view(img), view(resizedImg), boost::gil::bilinear_sampler()); boost::gil::write_view(OutStream, boost::gil::const_view(resizedImg), T()); Thanks, Lloyd

2 4

bjam resources
by Antonis Polykratis 18 Jul '20

18 Jul '20

Hello, are there any bjam tutorials documentation about how I could create a project using bjam? Thanks

3 2

Boost ABI/Linkage of clang vs g++
by DV Henkel-Wallace 17 Jul '20

17 Jul '20

boost-users(a)lists.boost.org We build with clang++-10 w/libc++.a and g++-10 w/libstdc++.a, so build a copy of boost in each configuration as well. This works great on the Mac development machines but the clang case doesn't generate the correct linkage on the Linux deployment machines. The correct clang linkage is std::__1::basic_string... but boost builds with std::__cxx11::basic_string Here's the linkage of libc++: $ objdump -T /usr/lib/llvm-10/lib/libc++.so.1|c++filt|grep ::basic_string|head -1 0000000000057450 g DF .text 0000000000000048 Base std::__1::locale::locale(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) Notice: std::__1::basic_string< ... When compiling my own code with clang++-10 the correct symbol is generated: $ nm options.cc.o |c++filt |fgrep __ |fgrep ::set_option_name |head -1 0000000000000000 W fmt::v6::basic_format_context<std::__1::back_insert_iterator<fmt::v6::internal::buffer<char> >, char>::iterator... Notice std::__1:: ... However the boost object have the wrong symbol name: $ nm 3P/llvm/lib/libboost_program_options.a |c++filt |fgrep __ |fgrep ::basic_string |head -1 0000000000000000 W boost::program_options::unknown_option::unknown_option(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) Notice std::__cxx11::basic_string< ... I'm compiling boost this way: export CC=clang CXX="clang++ -stdlib=libc++" CXXSTD=c++20 ; ./b2 stdlib=libc++ toolset=clang boost.locale.icu=off boost.locale.std=off --with-atomic --with-chrono --with-date_time --with-headers --with-locale --with-log --with-program_options --with-random --with-regex --with-system --with-thread threading=multi -sNO_COMPRESSION=1 link=static install It's 1.73.0

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[release] Boost 1.74.0 beta 1 released
by Marshall Clow 16 Jul '20

16 Jul '20

Boost release 1.74.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.74.0.beta.1/source/> The SHA256 checksums are as follows: 577a6b575ff2c227e14cce1b929c73d969475e58f3d2ab2901ad234f773bbd12 boost_1_74_0_b1.7z ba09c72dc848e7c0904922967014d853897b5a634926c910cc3b1fd627c31605 boost_1_74_0_b1.tar.bz2 2ccdc39efa076822cf1b359f9449f9d07707f3e27a18b393297b25885a9ff45b boost_1_74_0_b1.tar.gz c267c450166e040a374eaddab5e583cef09f6c3fe96a4db826172d0315c38dd5 boost_1_74_0_b1.zip For details of what's in the release, see < https://www.boost.org/users/history/version_1_74_0.html>. Please download the beta, give it a try, and report any problems you encounter. Issues that were found during the beta release process and will be fixed for the final 1.74.0 release: * The Boost.STLInterfaces documentation was left out of the beta. * Some of the Boost.Geometry documentation files have very long names; this could cause problems on platforms (like Windows) with shorter limits on path lengths. * There is a compile error in Boost.ASIO when compiling with 32-bit MSVC-14.2 with BOOST_BEAST_NO_TS_EXECUTORS. Thanks, -- The Boost Release Team

1 0

[release] Boost 1.74.0 Beta 1 Release Candidate 1
by Marshall Clow 14 Jul '20

14 Jul '20

The release candidates for the first 1.74.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.74.0.beta.1/source/ The release notes are not yet available. The SHA256 checksums are as follows: 577a6b575ff2c227e14cce1b929c73d969475e58f3d2ab2901ad234f773bbd12 boost_1_74_0_b1_rc1.7z ba09c72dc848e7c0904922967014d853897b5a634926c910cc3b1fd627c31605 boost_1_74_0_b1_rc1.tar.bz2 2ccdc39efa076822cf1b359f9449f9d07707f3e27a18b393297b25885a9ff45b boost_1_74_0_b1_rc1.tar.gz c267c450166e040a374eaddab5e583cef09f6c3fe96a4db826172d0315c38dd5 boost_1_74_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 Boost Release Managers

3 4

bjam using boost-1.77
by Cho-Kuen Ng 11 Jul '20

11 Jul '20

I used to use a very old version of bjam and wanted to switch to the most recent version 1.77. When I use the new bjam, I encounter the following problems. o I have 2 projects with the same id, the error message is error: at nml/unit_test/Jamfile:1 error: Attempt to redeclare already registered project id '/test'. error: Original project: error: Name: Jamfile</Users/cho/work/distmesh/unit_test> error: Module: Jamfile</Users/cho/work/distmesh/unit_test> error: Main id: /test error: File: distmesh/unit_test/Jamfile error: Location: distmesh/unit_test error: New project: error: Module: Jamfile</Users/cho/work//nml/unit_test> error: File: nml/unit_test/Jamfile error: Location: nml/unit_test After I changed the id in one project, the errors disappeared. o I do bjam again, I have this error /Users/cho//doc/boost/boost_1_73_0/tools/build/src/build/generators.jam:1127: in ensure-type from module generators error: target { PNCDF_Variable.C. } has no type Once I changed the C extension to cpp, the error disappeared. I don't have these problems using the old bjam. Are there syntax changes in the Jamfile? Please help. Thanks, Cho

1 0

[InterProcess] receiving notification when an item is added to the message queue
by Sean Farrow 11 Jul '20

11 Jul '20

Good afternoon, I am looking to use the message queue in the Interprocess library to communicate between two Windows processes. I was wondering whether there was an in-built mechanism to signal to the process reading from the queue that a message is available for consumption. If there isn't anything in-built, I was wondering what the best way to do this is and whether anybody has any working sample code they would be willing to share? Any help appreciated as always. Kind regards Sean.

2 1

Re: [Boost-users] Boost ABI/Linkage of clang vs g++
by DV Henkel-Wallace 10 Jul '20

10 Jul '20

> Date: Thu, 9 Jul 2020 16:44:58 +0100 > From: <pbristow(a)hetp.u-net.com> > > Does b2 -debug-configuration help? > > https://boostorg.github.io/build/manual/master/index.html section 3.3 configuration > > ? > You can use the --debug-configuration option to find which configuration files are actually loaded. Thanks, Paul, this helped me figure out a colleague had modified a .jam file and checked it in. -d

1 0

[ASIO] Using boost::asio::thread_pool with sockets without boost::asio::io_context
by Aniruddh Agarwal 09 Jul '20

09 Jul '20

Hello, One strategy to load-balance I/O processing across multiple threads is to use a single io_context object for multiplexing and to call io_context::run from all threads in the thread pool. This can be set up by, for example, defining a type which holds a vector of threads, all of which are calling io_context::run. My first question is: is this approach of calling io_context::run from several threads somewhat equivalent to using boost::asio::thread_pool as the default execution context and not (explicitly, at least) creating a boost::asio::io_context object at all? Somewhat more specifically, is it safe to define TCP sockets/acceptors/etc. with execution contexts set to a boost::asio::thread_pool instead of io_context, and will that work as expected (i.e., as a single io_context object scheduling tasks out to several threads calling io_context::run would)? -Ani

2 3

Concurrency support in iostream mapped_file_source
by Lloyd 03 Jul '20

03 Jul '20

Hi, Does boost iostream mapped_file_source support concurrent read from multiple threads? What is the best way to implement concurrent read on a performance sensitive application? The file is a read only one and its size is in gigabytes/terabytes Thanks, Lloyd

3 2

[serialization] Backward compatibility problem with 1:73
by Kai Benndorf 25 Jun '20

25 Jun '20

Hi all, we are using boost serialization for writing and reading data and just switched from boost 1:67 to boost 1:73. We now cannot read back the data written with boost 1:67 or prior. We get an archive_exception::input_stream_error exception. Examining the files shows the difference. The old files are starting with 22 serialization::archive 16 The new files are missing this data. Removing it from the files enabled the reading with boost 1:73. But strangely, if trying a small example program (the gps example from the documentation) also boost 1:73 produces this data: 22 serialization::archive 18 Any idea what has changed in between these versions and could cause this problem? Thanks in advance for any hint. Our application uses an own derived archive class. Maybe I have to changed something there? Best regards Kai Benndorf ---------------------------------------------------------------- Kai Benndorf E-Mail: kai.benndorf(a)web.de Zur Maibolte 44 MOBILE: 0151 55627946 32657 Lemgo WORK: 05251 150623 Germany PHONE: 05261 14465 ----------------------------------------------------------------

1 1

[boost][mp11][GIL]
by Debabrata Mandal 18 Jun '20

18 Jun '20

Hi, I am trying to implement a histogram class that will be able to store tuples of any data type. Most likely, I chose std::tuple for the job. So, in brief I used std::tuple as the key type in an unordered_map. I used boost::hash_value to supply the hasher in place of std::hash in the third template argument to unordered_map. Now, fast forwarding to my problem, I want to be able to provide a sub-histogram based on a few axes of the histogram. The code below, quite similar to what I want, refuses to work with msvc-14.0 (coming to it shortly). ----Sample Code---- #include <boost/mp11.hpp> template<typename... T> struct histogram { using type_list = boost::mp11::mp_list<T...>; template<std::size_t... D> void d() { // Error in below line histogram<boost::mp11::mp_at_c<type_list, D>...> f; } }; int main() { histogram<int, int, int, int> f; f.d<1,2>(); return 0; } ---END--- So, msvc-14.0 gives the error (after tracing to the last function call in stack) at the position specified above. The error message which is coming from the AppVeyor logs (since I do not have msvc-14.0) ... C:\projects\boost-root\boost/mp11/utility.hpp(53): error C2971: 'boost::mp11::detail::mp_if_c_impl': template parameter 'C': 'C': a variable with non-static storage duration cannot be used as a non-type argument C:\projects\boost-root\boost/mp11/utility.hpp(38): note: see declaration of 'boost::mp11::detail::mp_if_c_impl' C:\projects\boost-root\boost/gil/histogram.hpp(247): note: see declaration of 'C' ... I am not sure if the issue is with mp11 or the msvc-14.0, but I did find some references which claim a similar issue with the latter case. This links <https://developercommunity.visualstudio.com/content/problem/719235/erroneou…> to a very similar case of the error C2971 which seems to be fixed in the future releases. Also, the code above compiles fine with GCC and Clang. Any comments or suggestions on this are most welcome. Thanks, Deb GSOC 2020 student in Boost.GIL

2 1

Re: [Boost-users] [boost] [review] [text] Text formal review
by Vinnie Falco 17 Jun '20

17 Jun '20

On Fri, Jun 12, 2020 at 10:36 AM Rainer Deyke via Boost <boost(a)lists.boost.org> wrote: > String layer: overall, a solution looking for a problem. I created boost::json::string to use instead of std::string for a couple of reasons: 1. It uses a type-erased, reference counted memory resource instead of Allocator template parameter 2. The class is laid out a certain way to greatly minimize its size 3. The class layout is optimized to keep the size of the enclosing variant (the JSON DOM value type) small 4. The API is the same for all C++ versions (unlike std::string) 5. It is not a class template I would like to know what are the exact _technical_ benefits of Boost.Text's String layer, beyond "because I don't like std::string" Thanks

3 4

Re: [Boost-users] Boost in xeus-cling jupyter kernel
by Giorgino R 16 Jun '20

16 Jun '20

> Ηi there, > > I ve been using boost (geometry) with xeus-cling kernel without any > issues, so far. I install boost from conda forge: > > conda install boost -c conda-forge > > I tried to include odeint.hpp without any issues on my cling environment: > > see also > https://stackoverflow.com/questions/61205040/how-do-i-use-boost-with-the-xe… > > BW > G > > > On Fri, 12 Jun 2020, 19:46 A. de Windt via Boost-users, < > boost-users(a)lists.boost.org> wrote: > >> Hi everyone, >> >> As my first post in this mailing list I would like to ask, has anyone >> tried using boost in a xeus-cling jupyter kernel? Or just cling? >> >> My plan is to use odeint in the jupyter notebook for some simulations. >> However I had issues when I tried to run one of the odeint examples. I >> originally posted my issue on stackoverlfow but didn;t get any feedback. So >> I'm going to mostly copy my original question in this email. >> >> >> https://stackoverflow.com/questions/61205040/how-do-i-use-boost-with-the-xe… >> >> I'm running Pop!_OS (ubuntu derivative) and apt installed boost >> (libboost-all-dev) from the default repositories. I know it has been >> installed properly since I can compile and run the simple boost odeint >> example with GCC. >> >> However when I tried to run the same example inside a jupyter notebook >> using the zeus-cling kernel I got an error while including the odeint >> header. I can recreate the error while executing this code: >> >> #pragma cling add_include_path("/usr/include")#include <boost/numeric/odeint.hpp> >> >> The error message I get is: >> >> In file included from input_line_8:1: >> In file included from /usr/include/boost/numeric/odeint.hpp:22: >> In file included from /usr/include/boost/numeric/odeint/config.hpp:44: >> In file included from /usr/include/boost/config.hpp:48: >> In file included from /usr/include/boost/config/stdlib/libstdcpp3.hpp:78: >> /usr/include/unistd.h:756:28: error: expected function body after function declarator >> extern __pid_t fork (void) __THROWNL; >> ^ >> /usr/include/unistd.h:869:11: fatal error: 'bits/getopt_posix.h' file not found >> # include <bits/getopt_posix.h> >> ^~~~~~~~~~~~~~~~~~~~~ >> Interpreter Error: >> >> From what I understand bits/getopt_posix.h is a GCC only header, thus I >> think the problem might be because the boost headers are configuring >> themselves as if they are compiling under GCC instead of cling/clang. >> >> My solution so far has been to submodule the boost super project into my >> repository and add all the include paths necessary to get odeint and it's >> dependencies to compile. This is fine since odeint is a header only library >> anyways. But I'm pretty sure there is a better solution to this problem. >> >> Thanks in advance and hope to hear from someone back soon. >> >> >> Cheers, >> Aaron M. de Windt >> >> _______________________________________________ >> Boost-users mailing list >> Boost-users(a)lists.boost.org >> https://lists.boost.org/mailman/listinfo.cgi/boost-users >> >

1 0

Boost in xeus-cling jupyter kernel
by A. de Windt 13 Jun '20

13 Jun '20

Hi everyone, As my first post in this mailing list I would like to ask, has anyone tried using boost in a xeus-cling jupyter kernel? Or just cling? My plan is to use odeint in the jupyter notebook for some simulations. However I had issues when I tried to run one of the odeint examples. I originally posted my issue on stackoverlfow but didn;t get any feedback. So I'm going to mostly copy my original question in this email. https://stackoverflow.com/questions/61205040/how-do-i-use-boost-with-the-xe… I'm running Pop!_OS (ubuntu derivative) and apt installed boost (libboost-all-dev) from the default repositories. I know it has been installed properly since I can compile and run the simple boost odeint example with GCC. However when I tried to run the same example inside a jupyter notebook using the zeus-cling kernel I got an error while including the odeint header. I can recreate the error while executing this code: #pragma cling add_include_path("/usr/include")#include <boost/numeric/odeint.hpp> The error message I get is: In file included from input_line_8:1: In file included from /usr/include/boost/numeric/odeint.hpp:22: In file included from /usr/include/boost/numeric/odeint/config.hpp:44: In file included from /usr/include/boost/config.hpp:48: In file included from /usr/include/boost/config/stdlib/libstdcpp3.hpp:78: /usr/include/unistd.h:756:28: error: expected function body after function declarator extern __pid_t fork (void) __THROWNL; ^ /usr/include/unistd.h:869:11: fatal error: 'bits/getopt_posix.h' file not found # include <bits/getopt_posix.h> ^~~~~~~~~~~~~~~~~~~~~ Interpreter Error: >From what I understand bits/getopt_posix.h is a GCC only header, thus I think the problem might be because the boost headers are configuring themselves as if they are compiling under GCC instead of cling/clang. My solution so far has been to submodule the boost super project into my repository and add all the include paths necessary to get odeint and it's dependencies to compile. This is fine since odeint is a header only library anyways. But I'm pretty sure there is a better solution to this problem. Thanks in advance and hope to hear from someone back soon. Cheers, Aaron M. de Windt

2 1

Re: [Boost-users] [boost] [review] [text] Text formal review
by Emil Dotchevski 13 Jun '20

13 Jun '20

On Fri, Jun 12, 2020 at 10:36 AM Rainer Deyke via Boost < boost(a)lists.boost.org> wrote: > String layer: overall, a solution looking for a problem. I tend to agree with this but I had assumed there is a reason why it exists. Zach indicated that he doesn't care much about it, so it probably should be deleted, but I don't feel strongly about this because there are plenty of C++ APIs which define their own string type, and I don't see this as a problem. In C++, we have many of everything.

1 0

[review] [text] Text review begins June 11
by Glen Fernandes 12 Jun '20

12 Jun '20

The Boost formal review of Zach Laine's Unicode library, Text, commences on June 11th and concludes June 20th. We welcome the participation of Boost developers and users, and the C++ community. Quote: This library includes three layers: - The string layer, a set of types that constitute "a better std::string" - The Unicode layer, consisting of the Unicode algorithms and data - The text layer, a set of types like the string layer types, but providing transparent Unicode support Code: https://github.com/tzlaine/text Docs: https://tzlaine.github.io/text Text requires C++14 or higher, and supports GCC 5+, Clang 3.6+, and MSVC 2017. Zach initially presented the library at C++Now in 2018. He also intends to standardize a library solution for Unicode based on this work. Talk: https://www.youtube.com/watch?v=944GjKxwMBo Slides: https://tinyurl.com/boost-text-slides Try the library today, and please consider submitting a review, or even contributing to the discussion next week. Glen

4 3

[asio] tcp non blocking sync read query (bug?)
by Keith Robinson 11 Jun '20

11 Jun '20

Hi, I'm sending data from one process to another using a tcp connection. Sender use scatter-gather to send the data using 3 buffers (total just over 2000 bytes). The reader uses 2 separate sync reads to read the data (using the asio free function read()) using a non blocking socket. Sometimes everything is fine, the 2 reads return the amount of data requested, but sometimes I see strange behaviour. I'm trying to work out whether I am doing something wrong, or whether I've stumbled across a bug. When it goes wrong for me, the second read always returns less data than I requested, along with the error code 'would_block'. I then loop, performing further reads (using the same buffer as before), eventually (one read, or multiple reads later) the read function returns the remainder of the data, but still with the error code 'would_block' set. However, when I check the contents of the buffer, it is not what I expected. I think, but haven't been able to confirm, that the start of the buffer is not the start of the data. 1. Is it expected that the read() free function, when the socket is non blocking, can return less data than requested, along with the error code 'would_block'? 2. If it is expected, does the buffer passed in subsequent reads have to be adjusted to read only the remaining about of data? 3. If the buffer does have to be changed to only read what is left, how does this work with scatter-gather reads using multiple buffers? As a little bit of extra info, I confirmed using tcpdump that the correct data is sent/received, although it arrives in 2 chunks (MTU size of 1500). This is on Linux using Boost 1.73.0. Cheers, Keith

3 3

[review] [text] Text formal review
by Glen Fernandes 11 Jun '20

11 Jun '20

Dear Boost community, The formal review of Zach Laine's Unicode library, Text, begins today (June 11th) and ends on June 20th. The library provides three layers: - The string layer, a set of types that constitute "a better std::string" - The Unicode layer, consisting of the Unicode algorithms and data - The text layer, a set of types like the string layer types, but providing transparent Unicode support Code: https://github.com/tzlaine/text Docs: https://tzlaine.github.io/text The master branch of the repository will be frozen for the duration of the review. Text requires C++14 or higher, and supports GCC 5+, Clang 3.6+, and MSVC 2017. Zach initially presented the library at C++Now in 2018. He also intends to standardize a library solution for Unicode based on this work. Talk: https://www.youtube.com/watch?v=944GjKxwMBo Slides: https://tinyurl.com/boost-text-slides We encourage your participation in this review. At a minimum, kindly state: - Whether you believe the library should be accepted into Boost * Any conditions for acceptance - Your name and knowledge of the problem domain. You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s) * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? Even if you are not submitting a formal review, your feedback on the library is welcome. Glen

1 0

Impossible to download a boost source from bintray: 403 Forbidden
by Eisuke Kawashima 08 Jun '20

08 Jun '20

Dear All, I cannot download a boost source from bintray, e.g., https://dl.bintray.com/boostorg/release/1.73.0/source/boost_1_73_0.tar.bz2 returns 403 Forbidden. OTOH, sourceforge works: https://sourceforge.net/projects/boost/files/boost/1.73.0/boost_1_73_0.tar.…. Best -- Eisuke Kawashima e.kawaschima+boost(a)gmail.com

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[review][LEAF] Review period is over
by Michael Caisse 04 Jun '20

04 Jun '20

I apologize for not sending this out earlier. The review period is officially complete. A few people have contacted me about completing reviews that they in the middle of and I will be waiting until after this coming weekend to publish the review results. Thank you to those that joined the conversation and provided a review. michael -- Michael Caisse Ciere Consulting ciere.com

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[SPAM] Boost.Container monotonic_buffer_resource and overaligned types
by Patrick Northon 03 Jun '20

03 Jun '20

Is there a reason why it won't allocated for anything over memory_resource::max_align? Inspecting the code, it seem to me that it would just work.

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[review][LEAF] Review of LEAF starts today : May 22 - May 31
by Michael Caisse 02 Jun '20

02 Jun '20

The Boost formal review of Emil Dotchevski's LEAF (Lightweight Error Augmentation Framework) library will take place from May 22 through May 31st. LEAF isn't just another error reporting library in the family of expected-like types. It provides a unique take on error handling which plays into usability, flexibility, and performance. Every software developer must deal with handling errors which makes this review relevant to all. Please participate! I will be grateful to receive a review based on whatever level of effort or time you can devote. LEAF is brought to us by Emil Dotchevski, the author of Boost.Exception. Similar to Boost.Exception, this library allows arbitrary error objects to be returned; however, unlike Boost.Exception it does not require dynamic memory. The library can be used with or without exception handling. The LEAF documentation highlights the following features: * Efficient delivery of arbitrary error objects to the correct error handling scope. * No dynamic memory allocations. * Compatible with std::error_code, errno and any other error code type. * Can be used with or without exception handling. * Support for multi-thread programming. "LEAF is designed with a strong bias towards the common use case where callers of functions which may fail check for success and forward errors up the call chain but do not handle them." LEAF offers a pattern matching facility to specify which errors to handle and how to handle them. Take a look at the 5-minute Introduction. <https://zajo.github.io/leaf/#introduction> You can find the source code to be reviewed here: <https://github.com/zajo/leaf/tree/review> You can find the documentation here: <https://zajo.github.io/leaf/> The documentation includes a tutorial, examples, reference, design rationale, and comparisons to other error handling approaches/libraries. There is a benchmark document also: <https://github.com/zajo/leaf/blob/master/benchmark/benchmark.md> and a whitepaper: <https://github.com/zajo/leaf/blob/master/doc/whitepaper.md> Please provide in your review information you think is valuable to understand your choice to ACCEPT or REJECT including LEAF as a Boost library. Please be explicit about your decision (ACCEPT or REJECT). Some other questions you might want to consider answering: - 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 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 here: <http://www.boost.org/community/reviews.html> Thank you for your effort in the Boost community. Happy coding - michael -- Michael Caisse Ciere Consulting ciere.com

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[review][LEAF] Additional reviews in progress?
by Michael Caisse 01 Jun '20

01 Jun '20

Anybody in the process of producing a review to submit? Please respond here or contact me directly. -- Michael Caisse Ciere Consulting ciere.com

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[review][LEAF] Review of LEAF
by Sorin Fetche 01 Jun '20

01 Jun '20

On Fri, May 22, 2020 at 2:37 AM Michael Caisse via Boost <boost(a)lists.boost.org> wrote: > > The Boost formal review of Emil Dotchevski's LEAF (Lightweight Error > Augmentation Framework) library will take place from May 22 through May > 31st. I wholeheartedly recommend ACCEPTing LEAF as a Boost library I base my recommendation on both the qualities of the library itself and the responsiveness and openness for feedback of its author. As a background, more than year ago, I evaluated error handling using LEAF in the context of an in-house support library for implementing C++ RESTful services. I consider the error handling for microservices based architectures very important because it needs to cover two, sometimes competing, requirements: - as debug logs are less than ideal in distributed systems, an error condition should capture and carry with it as much context and debug information as possible as it propagates back across the stack (both in-process and across different processes/services); - the end-user of the system should not just get a dump of meaningless debug information when an error condition occurred (but neither just a generic "internal error occurred" one). And, coming from the experience of using Boost.Exception for an earlier version of such a utility library, LEAF seemed a very good candidate. So, as part of this evaluation, I tried to see how it would fit alongside Boost.Asio and Boost.Beast in building this REST oriented scaffolding. Through the course of this experimentation, LEAF improved its support for being used with Asio style asynchronous operations and multi-threading. It also includes now an example built at that time that showcases a possible way for how this integration can be be achieved. > - What is your evaluation of the design? Excellent as it allows bridging multiple error handling strategies and usage patterns in an efficient way. I view it as a clear successor to Boost.Exception and has very good interoperability with Boost.Outcome. > - What is your evaluation of the implementation? I have not studied it in depth but from what I can tell, as a user of the library, it is very solid. > - What is your evaluation of the documentation? Excellent! > - What is your evaluation of the potential usefulness of the library? It might not cover any possible usage scenario with error reporting and handling being such a generic problem space that often has conflicting requirements, but for sure it covers enough of it to warrant its inclusion in Boost. > - Did you try to use the library? With which compiler(s)? Did you > have any problems? Yes, extensively last year. Less so, recently [*] Tried it with Visual Studio 2019, g++ 7.3 and 8.2, clang 7.0 > - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? In depth study and usage about an year ago. Following the changes it has suffered since then (nothing significant from what I can tell). > - Are you knowledgeable about the problem domain? > I have used multiple error handling libraries over time. And, I also had to deal with distributed systems that had an improper or lacking error handling design, something simply slapped on as an afterthought. [*] The part of the project requiring C++ based services and by extension the infrastructure to enable writing them has been postponed as we (the team I'm part of) focused more on the environment where these services would run. I expect we'll resume this work sometime later this year. And at that time we'll start using the LEAF library again. Best regards, Sorin Fetche

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[review][LEAF] Review period ending soon - May 31
by Michael Caisse 30 May '20

30 May '20

I'd like to encourage each of you to review Emil's error handling library. We often focus on design or implementation based reviews, and I encourage those but what I would really like to see are more user based reviews. Grab the library and docs and play with it a bit. What works well? What can be improved? As a reminder, some of LEAF's features include: * arbitrary error types * header-only * no dependencies * use without exceptions * use with exceptions * no dynamic memory alloc You can find the documentation here: <https://zajo.github.io/leaf/> and the library source here: <https://github.com/zajo/leaf/tree/review> Thanks! michael -- Michael Caisse Ciere Consulting ciere.com

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installing boost in mac
by RUIZ PUJADAS, Esmeralda 30 May '20

30 May '20

Hello, I wanted to install the version 1.67 in mac as i have it in windows (the newest version 1.73 is not working for me) but i read that it is not compatible with mac. The version compatible with mac is above 1.69. So i decided to install this one. If I am mistaken let me know. I wanted to ask you if it is normal to get 524 warnings. All the warnings say the same: warning: empty macro arguments are a C99 feature [-Wc99-extensions] I just did it like this FrankGrimes:Desktop user$ cd boost_1_69_0 FrankGrimes:boost_1_69_0 user$ ./bootstrap.sh --prefix=/Users/user/boost FrankGrimes:boost_1_69_0 user$ ./b2 install Thise warnings will have any influence with my code. I am using xcode and I am having errors with boost due to unused parameters in args in filter_parser.hpp functions so i do not know if this error has something to do with it. Thanks

3 2

[Boost.Graph] Custom vertex properties with std::shared_ptr member ?
by Nicholas Yue 26 May '20

26 May '20

Hi, struct CustomVertex { std::string name; std::shared_ptr<AbstractNodeClass> _node; }; typedef boost::adjacency_list < boost::vecS, boost::vecS, boost::bidirectionalS, CustomVertex> Graph; Vertex DGManager::createVertex(const std::string &name, std::shared_ptr<AbstractNodeClass> Ptr) { _activeVertex = boost::add_vertex(CustomVertex{name, nodePtr}, _g); return _activeVertex; } With Visual Studio 2017, the above is fine but with GCC 7.5.0, I get a seg-fault on application exit. Looking at the stack trace, it looks like a problem in the CustomVertex destructor. Is there some restriction as to what types we can use as member variable of Custom Vertex Properties ? Kind regards -- Nicholas Yue Graphics - Arnold, Alembic, RenderMan, OpenGL, HDF5 Custom Dev - C++ porting, OSX, Linux, Windows http://au.linkedin.com/in/nicholasyue https://vimeo.com/channels/naiadtools

1 0

boost build from source code
by Leonid Meyerovich 21 May '20

21 May '20

Hello, bootstrao.sh file on Linux machine create b2 executable (copy it on boost root directory) cd "$pwd" BJAM="$my_dir/tools/build/src/engine/b2" echo "tools/build/src/engine/b2" cp "$BJAM" . Running b2 shows the error ./b2 bash: ./b2: cannot execute binary file: Exec format error Can somebody explain? Thank you, Leonid ________________________________ This message and all attachments are PRIVATE, and contain information that is PROPRIETARY to Intelligent Automation, Inc. You are not authorized to transmit or otherwise disclose this message or any attachments to any third party whatsoever without the express written consent of Intelligent Automation, Inc. If you received this message in error or you are not willing to view this message or any attachments on a confidential basis, please immediately delete this email and any attachments and notify Intelligent Automation, Inc.

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Review Wizard Status Report for May 2020
by Mateusz Loskot 20 May '20

20 May '20

============================================== Review Wizard Status Report for May 2020 ============================================== News ==== List of events that happened since the last report in 2016 is long and includes 13 releases of Boost, 21 libraries accepted and 4 libraries rejected. Details at https://www.boost.org/community/review_schedule.html What happened in 2020: 1. 2020-01: Ronald Garcia retired as a Review Wizard. Thank you Ronald! 2. 2020-02: StaticString accepted 3. 2020-04: Boost 1.73 Released New Libraries: - Nowide from Artyom Beilis, maintained by Alexander Grund - StaticString from Vinnie Falco and Krystian Stasiowski 4. 2020-05: Bimap library needs a maintainer https://lists.boost.org/Archives/boost/2020/05/248940.php Review Schedule Status ====================== The following libraries need a review manager: * JSON - author: Vinnie Falco, Krystian Stasiowski, Peter Dimov The following libraries have review managers, but have not yet been scheduled for review: * none The following libraries have review managers and have been scheduled for review: * LEAF - May 22, 2020 - May 31, 2020; author: Emil Dotchevski; review manager: Michael Caisse * Text - June 11, 2020 - June 20, 2020; author: Zach Laine; review manager: Glen Fernandes The following libraries have been reviewed and await reports from their review managers: * none The following libraries have been accepted to Boost, but have not yet been integrated into Boost Git: * Double-Ended - conditionally accepted in October 2017; author: Benedek Thaler * Parallel Sorting Sub-library - accepted November 2016; author: Francisco José Tapia The following libraries have been accepted and submitted to Boost Git, but have not yet appeared in a release: * STLInterfaces - conditionally accepted December 2019; author: Zach Laine The following libraries have been accepted provisionally to Boost, but have not been submitted for mini-review and full acceptance: * STLInterfaces - conditionally accepted December 2019; author: Zach Laine General Announcements ===================== As always, we need experienced review managers. Please take a look at the list of libraries in need of managers and check out their descriptions. In general review managers are active boost participants, including library contributors, infrastructure contributors, and other mailing list participants with a substantial track record of constructive participation. If you can serve as review manager for any of them, email us at Mateusz Loskot (mateusz at loskot dot net) or John Phillips (johnphillipsithaca at gmail dot com). We are also suffering from a lack of reviewers. While we all understand time pressures and the need to complete paying work, the strength of Boost is based on the detailed and informed reviews submitted by you. If you are interested in reviewing a library but won't have time during the review period, you can always prepare your review ahead of time. No rule says you can only work on a review during the review period. A link to this report will be posted to www.boost.org. If you would like us to make any modifications or additions to this report, please email Mateusz. The review schedule is an unordered list of the libraries awaiting review. As such, any library on the schedule can be reviewed once the developer is ready, a review manager has been secured, and the manager, developer, and wizards agree on a date to schedule the review. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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ubuntu cross-compile boost library for ARM
by Leonid Meyerovich 19 May '20

19 May '20

Hello Everyone, I have spent some time trying to build BOOST libraries from source code on Ubuntu machine. BOOST version is boost_1_73_0. I use ARM compiler echo $CC arm-oe-linux-gnueabi-gcc -march=armv7-a -mfloat-abi=hard -mfpu=neon --sysroot=/home/lm/rfnoc/oe/sysroots/armv7ahf-vfp-neon-oe-linux-gnueabi My current directory is boost_1_73_0 1. I have edited user-config.jam file, adding gcc_root = $(CC) ; using gcc : arm : $(gcc_root) This file is located on 'parent' BOOST directory - boost_1_73_0. 2. Run lm@ubuntu:~/boost/boost_1_73_0$ ./bootstrap.sh --prefix=bbb Building Boost.Build engine with toolset gcc... tools/build/src/engine/b2 Detecting Python version... 2.7 Detecting Python root... /home/lm/rfnoc/oe/sysroots/x86_64-oesdk-linux/usr Unicode/ICU support for Boost.Regex?... /usr Backing up existing Boost.Build configuration in project-config.jam.4 Generating Boost.Build configuration in project-config.jam for gcc... Bootstrapping is done. To build, run: ./b2 To generate header files, run: ./b2 headers To adjust configuration, edit 'project-config.jam'. Further information: - Command line help: ./b2 --help - Getting started guide: http://www.boost.org/more/getting_started/unix-variants.html - Boost.Build documentation: http://www.boost.org/build/ 3. So far it looks OK, I run b2 and have got an error lm@ubuntu:~ /boost/boost_1_73_0$ b2 /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/tools/features/warnings-feature.jam:27: in load ERROR: rule "[[bbv2.builtin.features.warnings]]`warnings`::" unknown in module "warnings-feature". /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/kernel/modules.jam:295: in import /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/tools/features/__init_features__.jam:22: in load /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/kernel/modules.jam:295: in import /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/tools/builtin.jam:16: in load /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/kernel/modules.jam:295: in import /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/build-system.jam:12: in load /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/kernel/modules.jam:295: in import /home/lm/covra-liquidsdr/boost/boost_1_73_0/tools/build/src/kernel/bootstrap.jam:139: in boost-build /home/lm/covra-liquidsdr/boost/boost_1_73_0/boost-build.jam:17: in module scope Could somebody explain what this error means and what I am doing wrong? Thank you, Leonid ________________________________ This message and all attachments are PRIVATE, and contain information that is PROPRIETARY to Intelligent Automation, Inc. You are not authorized to transmit or otherwise disclose this message or any attachments to any third party whatsoever without the express written consent of Intelligent Automation, Inc. If you received this message in error or you are not willing to view this message or any attachments on a confidential basis, please immediately delete this email and any attachments and notify Intelligent Automation, Inc.

1 0

BoostDLL : Multiple plugins in a single *.so/*.dll file
by Nicholas Yue 18 May '20

18 May '20

Hi, I am currently able to load each plugin in a given shared library. i.e. one plugin for each corresponding *.so/*.dll file However, as the number of plugins increases, I am wondering if there is a way to structure my plugins so that it all resides in a single *.so/*.dll file Additionally, how should one create the individual plugins in a single *.so/*.dll to be able to call their static method ? I have not found such examples so I am not sure if I am using the wrong search terms or it is currently not supported by design in BoostDLL. Cheers -- Nicholas Yue Graphics - Arnold, Alembic, RenderMan, OpenGL, HDF5 Custom Dev - C++ porting, OSX, Linux, Windows http://au.linkedin.com/in/nicholasyue https://vimeo.com/channels/naiadtools

3 3

[Multiprecision] number conversion to __int128
by A.Dmitrovsky 18 May '20

18 May '20

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[Boost.Test] Three-way comparison operator
by Leo Carreon 17 May '20

17 May '20

Hi Boosters, Does anyone know if Boost.Test has been updated to provide support for the three-way comparison operator? I’m asking because I’ve encountered a situation where my user-defined class provides the three-way comparison operator but when I perform comparisons using Boost.Test it complains that my class has no ‘operator==’ which is true because it provides ‘operator<=>’. Please note that I’m using Boost 1.73.0 and g++ 10.0.1. Is there any plan to add the three-way comparison operator support? Kind regards, Leo

2 1

warning C4275, C4271when using boost::noncopyable
by Roman Savchenko 14 May '20

14 May '20

Hi All, I'm trying to update from boost 1.62 to boost 1.73. Boost 1.62 was built with VS15 140 toolchain with shared runtime (/MD) and as static lib. Boost 1.73 was built with VS19 140 toolchain with /MD and as static lib. I have a class: #include <boost/noncopyable.h> class __declspec(dllexport) A : private boost::noncopyable when I'm using 1.62 I do not have such warning. when I'm using 1.73 I do have such warning. I'll appreciate if anyone could help me to understand what I'm missing. Why does new version of header generate this warning? Thanks, Roman

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(no subject)
by Ritajit Kundu 11 May '20

11 May '20

I am trying to compute a 2 Dimensional numerical integration with the help of Boost. I've been reading the documentation for a couple of days and my CPP language knowledge is just up to legacy CPP level so I'm a noob. I saw this page <https://www.boost.org/doc/libs/1_73_0/libs/math/doc/html/math_toolkit/gauss…> in documentation which calculates the quadrature using* Gauss-Kronrod *rule. I was trying to build upon it and calculate a 2-d integral using Gauss-Kronrod rule. My understanding is *a 2D integral is basically 2 1D integrals with the Cartesian product.* So I was thinking If I can nest two integration function then I'm done. I've started from the aforementioned example and extended it a bit so the code for a 2d integration looks like, #include <boost/math/quadrature/gauss_kronrod.hpp> #include <iostream> int main(int argc, char *argv[]) { using namespace boost::math::quadrature; auto f1 = [](double t, double s) { return std::exp(-(t*t+s*s+t*s) / 2); }; double error; double Q = gauss_kronrod<double, 15>::integrate(gauss_kronrod<double, 61>::integrate(f1, 0, std::numeric_limits<double>::infinity(), 5), 0, std::numeric_limits<double>::infinity(), 5, 1e-9, &error); std::cout << Q << " " << error<<std::endl; return 0; } . I've just added a lambda function (which is the integrand) of two variables and nested 2 1D Gauss-Kronrod integration functions. I'm compiling this with g++ -Wall -I /path/to/boost_1_73_0 2d-gauss.cpp This gives error and compilation fails. I don't know what wrong I'm doing. How do you suggest to do such an integral? Thanks in advance.

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Google Summer of Code 2020 selected projects
by David Bellot 09 May '20

09 May '20

Dear Boost community, I would like to welcome our Google Summer of Code. 2020 students. This year, 10 students will work very very hard on improving and adding new features to many of our libraries. Once again, the competition has been very hard. A few numbers: - we received 93 proposals in total. 85 of them were complete, then we kept 47 proposals only - finally we selected 10 of them, covering 7 different Boost libraries - and countless hours of work from the most incredible team of mentors! Here are the list of projects for 2020: *Boost.Real* Kishan Shukla will be working on making the Real library ready for revision. His main goal is to reimplement the division algorithm so it can be used with any number base representation and the Karatsuba multiplication algorithm. Also, it will be working on implementing some operators and common irratianal numbers as Pi. Mentors: Laouen Belloli and Damian Vicino. *Boost.Astronomy* Syed Ali Hasan will be working on the astronomical coordinate system, he will implement different coordinate conversion using SOFA library Mentor: Pranam Lashkari Gopi Krishna Menon will be completing the parser for FITS file and also optimise the already developed components. Mentor: Sarthak Singhal *Boost.GIL* Debabrata Mandal will be implementing histogram computation as a built-in feature, algorithms for histogram analysis, image processing algorithms based on histogram and possibly integration with Boost.Histogram library. *Mentor*: Mateusz Loskot, Pranam Lashkari Olzhas Zhumabek will be extending GIL's portfolio of image processing algorithms, implementing for image scaling and sampling, Perona–Malik diffusion, Non-Maximum Suppression for object detection, Hysteresis threshold and some more. *Mentor*: Mateusz Loskot *Boost.Multiprecision* Dimitris Los will work on extending and optimizing parts of Boost.Multiprecision to higher precision of many thousands of bits or more. *Mentor*: Christopher Kormanyos *Boost.uBlas* Ashar Khan will stabilize and improve Boost.uBlas using the C++20-Standard. The main focus of his project will be enhancing code-coverage and documentation, integrating static code analysis and generating tensor concepts. *Mentor*: Cem Bassoy Tom Kwok will improve and finalize the implementation of data frames in uBlas, with the aim of delivering production-ready by the end of the summer. Data frame in uBlas are similar in functionalities to other implementations like in R, Python.Pandas or Julia. *Mentor*: David Bellot *Boost.Geometry* Tinko Bartels will work on robust yet efficient geometric predicates for Boost Geometry. *Mentor*: Vissarion Fisikopoulos *Boost.Real* Vikram Singh Chundawat will work in taking Real to revision ready state. His focus will be in improving the internal representation datatypes and providing functions required to conveniently support Taylor series. *Mentors*: Damian Vicino and Laouen Belloli Best regards, David Bellot

1 0

boost::filesystem::perms on Windows
by Dominique Devienne 07 May '20

07 May '20

Hi. I'm not having any luck with finding out whether a folder is writable or not, on Windows. Is Boost.Filesystem (1.64) supposed to work on Windows for permissions? Especially in "special" folders like those in "C:\Program Files"? C:\Program Files\Vendor\App>echo foo > bar Access is denied. But Boost.Filesystem reports permissions as rw-rw-rw-, when printing them using the BFS-equivalent to the example available on CppReference https://en.cppreference.com/w/cpp/filesystem/perms Despite obviously the folder not being writable, w/o being an administrator. I'm naively using simple code like below: ``` fs::path path(name); fs::file_status stat = fs::status(path); fs::perms p = stat.permissions(); demo_perms(p); ``` Am I missing something obvious? Thanks, --DD PS: I worked around the above, actually trying to create a file, but that has corner cases too, and I'd much prefer a reliable and cross-platform .permissions() from Boost. Smoothing-over platform differences is one "raison d'etre" from Boost after all, no?

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Fwd: [serialization] is the weak_ptr parent kept inside an iarchive
by ypotin 06 May '20

06 May '20

Hello, I was running some tests involving std::weak_ptr using boost serialization, and I realized that when I read a std::weak_ptr from an archive that doesn't contain the "parent" std::share_ptr, the behavior of the read pointer is "hard to understand". Here is an example : #include <cassert> #include <sstream> #include <memory> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/binary_oarchive.hpp> #include <boost/serialization/export.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/serialization/weak_ptr.hpp> class MyInt { public: MyInt() : value(0) { } int value; template<class Archive> void serialize(Archive &ar, unsigned int) { ar & value; } }; int main() { std::stringstream data; { std::shared_ptr<MyInt> shared = std::make_shared<MyInt>(); assert(shared.use_count() == 1); shared->value = 12; /* Write a weak_ptr */ { std::weak_ptr<MyInt> weak(shared); assert(shared.use_count() == 1); boost::archive::binary_oarchive ar(data); ar << weak; assert(shared.use_count() == 1); } assert(shared.use_count() == 1); /* Read a weak_ptr */ std::weak_ptr<MyInt> weak; { boost::archive::binary_iarchive ar(data); ar >> weak; assert(shared.use_count() == 1); assert(weak.use_count() == 1); { std::shared_ptr<MyInt> loaded = weak.lock(); assert(loaded); /* It looks good */ assert(loaded->value == 12); /* Let's see... */ assert(loaded != shared); shared->value = 42; assert(loaded->value == 12); /* So another shared_ptr exists somewhere... */ assert(shared.use_count() == 1); assert(loaded.use_count() == 2); assert(weak.use_count() == 2); } /* But where ? */ assert(shared.use_count() == 1); assert(weak.use_count() == 1); } /* Let's see */ assert(shared.use_count() == 1); assert(weak.use_count() == 0 /* weak.expired() */); /* Hmm, was it inside the archive itself ? */ } /* Let's try again, we need the input stream to be back to the beginning */ data.seekg(0); std::weak_ptr<MyInt> weak; { boost::archive::binary_iarchive ar(data); assert(weak.use_count() == 0); ar >> weak; assert(weak.use_count() == 1); /* It looks fine */ } assert(weak.use_count() == 0); /* aw, on a second thought, it really doesn't */ return 0; } I am building and running this using g++-9.3.0 with boost-1.72.0-1. Clearly, the weak_ptr gets itself a shared_ptr "somewhere" as it can be used after being read. I was wondering "where it is stored and how to access it, if possible, without some `weak.lock()` call ?" It looks like the shared_ptr gets destroyed at the same time as the archive, so I guess it is cleaned up thanks to the delete_created_pointers method when the iarchive is destroyed : does delete_created_pointers actually contains also shared_ptr ? As far as I can see in the code serialization/weak_ptr.hpp, we actually save then load a std::shared_ptr, so I was expecting the weak_ptr to expire as soon as the call returns : since it is not, there *is* another reference. Now, I know I must save the shared_ptr in the archive myself to have my own reference and to get all weak_ptr running properly. But I came across this use case and I can't take it out of my mind, so if you have an explanation, I'm all ears. Thank you

1 0

Boost 1.73, beast and -fconcepts
by David P. Riedel 04 May '20

04 May '20

Hi It seems that beast still does not work with gcc 9.3 and -fconcepts. If I try to build the beast test programs using -fconcepts, I still get a lot of errors such as those below. I thought this was fixed in 1.73. ???? Thanks --------------------- In file included from ../../../boost/beast/core/basic_stream.hpp:1457, from ../../../boost/beast/core.hpp:16, from doc/core_snippets.cpp:19: ../../../boost/beast/core/impl/basic_stream.hpp:781:1: error: no declaration matches ‘auto boost::beast::basic_stream< <template-parameter-1-1>, <template-parameter-1-2>, <template-parameter-1-3> >::async_connect(const endpoint_type&, ConnectHandler&&)’ 781 | basic_stream<Protocol, Executor, RatePolicy>:: | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from ../../../boost/beast/core.hpp:16, from doc/core_snippets.cpp:19: ../../../boost/beast/core/basic_stream.hpp:1202:5: note: candidates are: ‘template<class Protocol, class Executor, class RatePolicy> template<class Iterator, class ConnectCondition, class IteratorConnectHandler> requires completion_token_for<IteratorConnectHandler, void()> typename boost::asio::async_result<typename std::decay<RangeConnectHandler>::type, void(boost::system::error_code, Iterator)>::return_type boost::beast::basic_stream< <template-parameter-1-1>, <template-parameter-1-2>, <template-parameter-1-3> >::async_connect(Iterator, Iterator, ConnectCondition, IteratorConnectHandler&&)’ 1202 | async_connect( | ^~~~~~~~~~~~~ ../../../boost/beast/core/basic_stream.hpp:1141:5: note: ‘template<class Protocol, class Executor, class RatePolicy> template<class Iterator, class IteratorConnectHandler> requires completion_token_for<IteratorConnectHandler, void()> typename boost::asio::async_result<typename std::decay<RangeConnectHandler>::type, void(boost::system::error_code, Iterator)>::return_type boost::beast::basic_stream< <template-parameter-1-1>, <template-parameter-1-2>, <template-parameter-1-3> >::async_connect(Iterator, Iterator, IteratorCon

2 2

[review] [LEAF] LEAF Review Starts May 22
by Michael Caisse 01 May '20

01 May '20

The Boost formal review for LEAF (Lightweight Error Augmentation Framework) will take place May 22, 2020 through May 31st. LEAF is brought to us by Emil Dotchevski, the author of Boost.Exception. Similar to Boost.Exception, this library allows arbitrary error objects to be returned; however, unlike Boost.Exception it does not require dynamic memory. The library can be used with or without exception handling. Error handling is such an import part of every software system. LEAF provides a unique solution to the problem. The excellent documentation can be found here: <https://zajo.github.io/leaf/> and includes a tutorial, examples, reference, design rationale, and comparisons to other error handling approaches/libraries. The source is available at github. The review branch will be used during the review period. <https://github.com/zajo/leaf/tree/review> The purpose of this announcement is to give people some time to start looking at the documentation and source code for the library. Feel free to begin asking questions. Most of all, get involved! Everybody has some experience with handling errors. Tell the Boost community what you think of LEAF. Thank you for your participation! michael -- Michael Caisse Ciere Consulting ciere.com

1 0

Three-way comparison operator
by Leo Carreon 30 Apr '20

30 Apr '20

Hi Boosters, Does anyone know if Boost.Test has been updated to provide support for the three-way comparison operator? I’m asking because I’ve encountered a situation where my user-defined class provides the three-way comparison operator but when I perform comparisons using Boost.Test it complains that my class has no ‘operator==’ which is true because it provides ‘operator<=>’. Please note that I’m using Boost 1.73.0 and g++ 10.0.1. Is there any plan to add the three-way comparison operator support? Kind regards, Leo

4 4

Windows boost::filesystem canonical on NTFS network drives mounted in a directory
by gga 29 Apr '20

29 Apr '20

When on Windows, if you use boost::filesystem::canonical() to resolve a NTFS network drive mounted in a directory, the result is what I see as a useless result. For example: C:\ntfs_mount\other\dirs\file boost::filesystem returns: C:\?VolumeXXX-XXX-XXX-XXX\ other\dirs\file This volume notation is useless as it cannot be passed to any file function. Also, the path is divided by a space to other\dirs. It would be better if canonical does not mess with the network drive at all and returns the directory as is, like boost::filesystem::absolute() does. -- Gonzalo Garramuño

1 0

[release] Boost 1.73.0
by Marshall Clow 28 Apr '20

28 Apr '20

Release 1.73.0 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 2 new libraries and numerous enhancements and bug fixes for existing libraries. For details, including download links, see < http://www.boost.org/users/news/version_1.73.0> You can also download directly from: < https://dl.bintray.com/boostorg/release/1.73.0/> 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, Micheal Caisse and Glen Fernandes

1 0

[release] Boost 1.73.0 Release Candidate 1
by Marshall Clow 26 Apr '20

26 Apr '20

The first release candidates for the 1.73.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.73.0/source/> The SHA256 checksums are as follows: d2e7501bb04fe7abc09aa93f013ae997604286a882da1bd36ddd96ea1163ea71 boost_1_73_0_rc1.7z 4eb3b8d442b426dc35346235c8733b5ae35ba431690e38c6a8263dce9fcbb402 boost_1_73_0_rc1.tar.bz2 9995e192e68528793755692917f9eb6422f3052a53c5e13ba278a228af6c7acf boost_1_73_0_rc1.tar.gz 0909a79524f857ef54570ceef8f397cc0629202532cc997785479c7c08bbc2a4 boost_1_73_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 7

Using coroutines in ASIO
by Pedro Pinto 25 Apr '20

25 Apr '20

Hi there, I am trying to compile the asio co-routine example but as far as I can tell boost is looking for an <experimental/coroutine> header that does not exist on my system. I am using boost 1.71 and gcc on ubuntu 20.04. I tried both stock gcc (v9 on ubuntu) which does not have a coroutine header and gcc 10 which does have it but not under the experimental directory. Here is the output with gcc 10: /usr/lib/ccache/g++ -I../../src -g -Wall -pedantic -Wextra -Werror -DASIO_HAS_CO_AWAIT -DBOOST_ASIO_HAS_CO_AWAIT -fcoroutines --std=c++2a -fdiagnostics-color -MD -MT CMakeFiles/mcbridge.dir /src/main.cpp.o -MF CMakeFiles/mcbridge.dir/src/main.cpp.o.d -o CMakeFiles/mcbridge.dir/src/main.cpp.o -c ../../src/main.cpp In file included from /usr/include/boost/asio/co_spawn.hpp:22, from ../../src/main.cpp:4: /usr/include/boost/asio/awaitable.hpp:22:10: fatal error: experimental/coroutine: No such file or directory 22 | #include <experimental/coroutine> Any ideas on how to compile this example?

2 1

10 slots for the Google Summer of Code 2020
by David Bellot 22 Apr '20

22 Apr '20

Hi Boost community, this year Google allocated 10 slots for the Google Summer of Code. It's again a great achievement thanks to the hard work of our team of dedicated mentors. We are now selecting the best students among all the proposals we receive. We received 79 proposals this year. 10 of them will be selected. This year, a lot of proposals if not all are targeting a finalization of the work which has been done in the previous GSoCs and we should see a lot of code being pushed in production. It's a very exciting time for all of us. The mentors are now hard at work to choose the students. We'll keep you informed when it's official. Best regards, David

1 0

Re: [Boost-users] [random_device] App crash on boost::ramdom::random_device
by 박형근(HYUNGGUN PARK) 22 Apr '20

22 Apr '20

> On Fri, Apr 17, 2020 at 10:29 AM 박형근(HYUNGGUN PARK) via Boost-users > <boost-users(a)lists.boost.org> wrote: > > > > My app crash on customer's site. It crashes everytime the app is > starting. > > It happens on Chinese Windows7 (64bit) OS but it runs well on my PC > > with > Korean Windows7 OS and English Windows7 OS. > > My app is built on VisualStudio 2010 (x86 build, C++) using > > websocketpp > library and boost 1.55. > > The call-stack from the dump file shows my app(TMSClient100) called > websocketpp::endpoint, then it called boost::random::random_device > then ThrowException. Here's the call-stack info: > > > > 14 001cf6ac 7113872d e06d7363 00000001 00000003 > > KERNELBASE!RaiseException+0x58 > > 15 001cf6e4 713b7c5a 001cf704 713d9350 b621b77b > > msvcr100!_CxxThrowException+0x48 > > [f:\dd\vctools\crt_bld\self_x86\crt\prebuild\eh\throw.cpp @ 157] > > 16 001cf814 713b7da3 001cf840 b621b9a7 002a19bc > > TMSClient100!boost::random::random_device::impl::error+0x15a > > 17 001cf8b8 713b7f7b 001cf8dc b621b94b 00000000 > > TMSClient100!boost::random::random_device::impl::impl+0x143 > > Check the exception message. Is it failing because it: > 1. Could not find a provider name > 2. Could not acquire CSP context > > If #1, this might be solved by upgrading from Boost 1.55 to a newer > version. This fix in particular: > https://github.com/boostorg/random/commit/dc2fdeac443fb56c87a03a0887c9 > e7c8 > e1d3296d > went into Boost 1.56. > > Glen Glen, Thank you for your reply. Thanks to your suggestion, upgrade from Boost 1.55 to 1.56 solved this problem. Thank you very much. Harry

1 0

[Boost] [test] strange behaviour when comparing floating point numbers
by Matthijs Möhlmann 21 Apr '20

21 Apr '20

Hi, I am trying to compare two floating point numbers but am encountering somewhat strange behaviour. The minimal compilable example: #define BOOST_TEST_MODULE tests #define BOOST_TEST_DYN_LINK #include <boost/test/unit_test.hpp> BOOST_AUTO_TEST_SUITE(testsuite) BOOST_AUTO_TEST_CASE(test1) { namespace tt = boost::test_tools; BOOST_TEST(0.1 == 0.2, tt::tolerance(0.01)); // will fail BOOST_TEST(0.1f == 0.2f, tt::tolerance(0.02)); // will fail too, but different error message... } BOOST_AUTO_TEST_SUITE_END() When compiling with: clang++ (clang version 7.0.1-8 (tags/RELEASE_701/final)) flags: -o main -g -std=c++17 -stdlib=libc++ -lboost_unit_test_framework main.cpp boost: 1.72.0 I'll get the following output: Running 1 test case... main.cpp(10): error: in "testsuite/test1": check 0.1 == 0.2 has failed [0.10000000000000001 != 0.20000000000000001]. Relative difference exceeds tolerance [1 > 0.01] main.cpp(11): error: in "testsuite/test1": check 0.1f == 0.2f has failed [0.100000001 != 0.200000003] *** 2 failures are detected in the test module "tests" Why am I getting two different messages? I expected those to be the same... Regards, Matthijs

2 2

[program_options] cmake discovery issue
by Jeanette C. 21 Apr '20

21 Apr '20

Hello, I can't say when these errors first appeared, certainly not in Boost 1.63 . I have a project working with cmake and the following cmmake lines: set(Boost_USE_MULTITHREADED ON) find_package(Boost 1.58 REQUIRED COMPONENTS program_options filesystem date_time system) if (Boost_PROGRAM_OPTIONS_FOUND) set (INCS ${INCS} ${Boost_INCLUDE_DIRS}) set (LIBS ${LIBS} ${Boost_PROGRAM_OPTIONS_LIBRARY} ${Boost_SYSTEM_LIBRARY}) endif (Boost_PROGRAM_OPTIONS_FOUND) Which says that it found the libraries and lower down produces this error: CMake Error in CMakeLists.txt: Imported target "Boost::program_options" includes non-existent path "/include" in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include: * The path was deleted, renamed, or moved to another location. * An install or uninstall procedure did not complete successfully. * The installation package was faulty and references files it does not provide. This error appears twice in the output. My cmake skills are too meagre to trace it to a particular point in the Boost Cmake modules. Could someone please help? Is it perhaps my fault for not updating a call somewhere? Best wishes and TIA, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * SoundCloud: https://soundcloud.com/jeanette_c * Twitter: https://twitter.com/jeanette_c_s * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c There's no time to loose And next week, You might not see me here <3 (Britney Spears)

1 0

Continuous Deployment of Boost.Beast-based server
by Dominique Devienne 21 Apr '20

21 Apr '20

Imagine I have a WebSocket server, implemented using Boost.Asio and Boost.Beast. It's deployed and serving clients in production or test environments, but I fixed a bug, checked in a fix, passed CI, and would like to redeploy, but w/o downtime for existing clients. New clients should use the same address, but be served by the newly deployed fixed server. While on-ongoing WebSocket connections keep on using the old server. Is that possible? In-process? Or one must use some kind of "front-end server" redirecting new traffic (i.e. new WebSocket session and/or HTTP requests) to separate processes? (nginx? little GoLang exe? In C++ Boost.Asio based? else?) If not possible in-process, then how to know when older server is no longer in use, to gracefully stop it? Asio servers typically run forever, i.e. never run out of work, even when they temporarily have nothing to do, by design. The goal is to do this on "premise" (i.e. not in the cloud), on a single machine (no containers), and cross-platform (Windows and Linux). Thanks, --DD

3 6

Building boost 1.72 with arm 64 bit gcc compiler
by Rahul Sreeram 20 Apr '20

20 Apr '20

Hi, I am trying to build boost 1.72 with arm 64 bit compiler. I am seeing the error: No best alternative for libs/context/build/asm_sources Although, after getting this error, compilation looks to succeed, but I am not sure if it did properly or not. I have this line in the project-config.jam: using gcc : arm : aarch64-fsl-linux-g++ --sysroot=/sysroots/aarch64-fsl-linux ; After running b2, I get the following output: ./b2 toolset=gcc-arm Performing configuration checks - default address-model : 64-bit - default architecture : arm Building the Boost C++ Libraries. error: No best alternative for libs/context/build/asm_sources next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>elf <threading>multi <toolset>qcc not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>aapcs <address-model>32 <architecture>arm <binary-format>pe <threading>multi <toolset>msvc not matched next alternative: required properties: <abi>aapcs <address-model>64 <architecture>arm <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>aapcs <address-model>64 <architecture>arm <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>aapcs <address-model>64 <architecture>arm <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>aapcs <address-model>64 <architecture>arm <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>o32 <address-model>32 <architecture>mips1 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>o32 <address-model>32 <architecture>mips1 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>n64 <address-model>64 <architecture>mips1 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>n64 <address-model>64 <architecture>mips1 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>xcoff <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>power <binary-format>xcoff <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>xcoff <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>power <binary-format>xcoff <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32_64 <architecture>power <binary-format>mach-o <threading>multi not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>riscv <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>s390x <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>elf <threading>multi <toolset>intel not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>32 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>clang not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>clang-win not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>intel not matched next alternative: required properties: <abi>ms <address-model>32 <architecture>x86 <binary-format>pe <threading>multi <toolset>msvc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>intel not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>clang not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>darwin not matched next alternative: required properties: <abi>sysv <address-model>64 <architecture>x86 <binary-format>mach-o <threading>multi <toolset>intel not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>clang not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>clang-win not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>intel not matched next alternative: required properties: <abi>ms <address-model>64 <architecture>x86 <binary-format>pe <threading>multi <toolset>msvc not matched next alternative: required properties: <abi>x32 <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>clang not matched next alternative: required properties: <abi>x32 <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>gcc not matched next alternative: required properties: <abi>x32 <address-model>64 <architecture>x86 <binary-format>elf <threading>multi <toolset>intel not matched next alternative: required properties: <abi>sysv <address-model>32_64 <architecture>x86 <binary-format>mach-o <threading>multi not matched next alternative: required properties: <abi>sysv <architecture>combined <binary-format>mach-o <threading>multi not matched - C++11 mutex : yes - lockfree boost::atomic_flag : yes - Boost.Config Feature Check: cxx11_auto_declarations : yes - Boost.Config Feature Check: cxx11_constexpr : yes - Boost.Config Feature Check: cxx11_defaulted_functions : yes - Boost.Config Feature Check: cxx11_final : yes - Boost.Config Feature Check: cxx11_hdr_mutex : yes - Boost.Config Feature Check: cxx11_hdr_tuple : yes - Boost.Config Feature Check: cxx11_lambdas : yes - Boost.Config Feature Check: cxx11_noexcept : yes ...... Regards, Rahul

3 2

[random_device] App crash on boost::ramdom::random_device
by 박형근(HYUNGGUN PARK) 17 Apr '20

17 Apr '20

Hi there! My app crash on customer's site. It crashes everytime the app is starting. It happens on Chinese Windows7 (64bit) OS but it runs well on my PC with Korean Windows7 OS and English Windows7 OS. My app is built on VisualStudio 2010 (x86 build, C++) using websocketpp library and boost 1.55. The call-stack from the dump file shows my app(TMSClient100) called websocketpp::endpoint, then it called boost::random::random_device then ThrowException. Here's the call-stack info: 14 001cf6ac 7113872d e06d7363 00000001 00000003 KERNELBASE!RaiseException+0x58 15 001cf6e4 713b7c5a 001cf704 713d9350 b621b77b msvcr100!_CxxThrowException+0x48 [f:\dd\vctools\crt_bld\self_x86\crt\prebuild\eh\throw.cpp @ 157] 16 001cf814 713b7da3 001cf840 b621b9a7 002a19bc TMSClient100!boost::random::random_device::impl::error+0x15a 17 001cf8b8 713b7f7b 001cf8dc b621b94b 00000000 TMSClient100!boost::random::random_device::impl::impl+0x143 18 001cf904 71383901 b621b8ab 001cfac4 002a17e8 TMSClient100!boost::random::random_device::random_device+0x8b 19 001cf928 7137eb2c 002a17e8 b621b8ef 001cfac4 TMSClient100!websocketpp::endpoint<websocketpp::connection<websocketpp::config::asio_client>,websocketpp::config::asio_client>::endpoint<websocketpp::connection<websocketpp::config::asio_client>,websocketpp::config::asio_client>+0x191 [d:\dev\tms\trunk\library\library_c++_3\websocketpp\websocketpp\endpoint.hpp @ 101] 1a 001cf96c 713598c2 002a1790 b621b83b 001cfa08 TMSClient100!TMS::CWebSocketClient::CWebSocketClient+0x9c [d:\dev\tms\trunk\library\library_c++_3\tmsclient100\websocketclient.cpp @ 15] 1b 001cf9b8 010316cd b620327e 00388fa8 0103c908 TMSClient100!TMS::CTMSClient::CTMSClient+0xf2 [d:\dev\tms\trunk\library\library_c++_3\src\tmsclient.cpp @ 25] Any suggestion how to debug this problem will be greatly appreciated. Harry Park

3 2

[release] Boost 1.72.0 Beta 1
by Marshall Clow 12 Apr '20

12 Apr '20

Boost release 1.73.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.73.0.beta.1/source/> The SHA256 checksums are as follows: 44f323b42c4375ab3751b67ac5ce53ba5267af20cf375be75675d8952d3cca4e ./boost_1_73_0_b1.7z 5270fa89243a3508331bd3773800de6d2f98d1f160b95e362fa8269d9cd58773 ./boost_1_73_0_b1.tar.bz2 82ffcd4a2e558a31f1ddd6a54ef6c00dae28b95c2ddee575c285544085dcb004 ./boost_1_73_0_b1.tar.gz 910b7560ee239472cc69e6a0c680dc4d9d7ea234faad807738ec98e4811c63d4 ./boost_1_73_0_b1.zip For details of what's in the release, see <https://www.boost.org/users/history/version_1_73_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

1 0

Help on anything to try...
by gga 12 Apr '20

12 Apr '20

I am facing a weird crash using boost asio when the client segfaults upon exit on the Release builds of my program after the server has closed the connection. The crash happens upon exit of the application (so my guess it is probably some static destructor crashing), not at the end of the connection to the server. The crash does not occur on the Debug version of my application, nor does asan report any memory trashing. The crash also does not happen if I don't do any network connections in my application (boost::asio does not run any io_services). The crash also happens on Linux only and not on Windows. I created a relatively smaller client/server program like my executable and there's no crash there either. I have run out of things to try. Can someone suggest something I can try to see where the crash is happening? -- Gonzalo Garramuño

2 3

[release] Boost 1.73.0 Beta 1 Release Candidate 1
by Marshall Clow 10 Apr '20

10 Apr '20

The release candidates for the first 1.73.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.73.0.beta.1/source/ The release notes are not yet available. The SHA256 checksums are as follows: 44f323b42c4375ab3751b67ac5ce53ba5267af20cf375be75675d8952d3cca4e ./boost_1_73_0_b1_rc1.7z 5270fa89243a3508331bd3773800de6d2f98d1f160b95e362fa8269d9cd58773 ./boost_1_73_0_b1_rc1.tar.bz2 82ffcd4a2e558a31f1ddd6a54ef6c00dae28b95c2ddee575c285544085dcb004 ./boost_1_73_0_b1_rc1.tar.gz 910b7560ee239472cc69e6a0c680dc4d9d7ea234faad807738ec98e4811c63d4 ./boost_1_73_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 Boost Release Managers

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404 GMane link in Boost.FileSystem doc
by Dominique Devienne 09 Apr '20

09 Apr '20

Hi. Over at https://www.boost.org/doc/libs/1_72_0/libs/filesystem/doc/reference.html#pa… (and older version of the doc too) there's a link to http://permalink.gmane.org/gmane.comp.lib.boost.devel/199744 which is no longer so permanent :). According to https://en.wikipedia.org/wiki/Gmane the website is no longer available. I guess any GMane link in docs should be updated to another ML archive. My $0.02. Thanks, --DD

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[program_options] cmake issues
by Jeanette C. 09 Apr '20

09 Apr '20

Hey hey, I get a cmake error about a non-existent directory from boost::program_options, namely /include . It only happens with the program_options library. Other libs included in the project are date_time, filesystem and system. A quick peak at /lib/cmake/boost_program_options-1.72.0/boost_program_options-config.cmake compared to the same file from date_time didn't give me any obvious hint though. But I'm not very familiar with cmake. The cmake line in my project to find these Boost packages is this: find_package(Boost 1.58 REQUIRED COMPONENTS program_options filesystem date_time system) Here's the error message when running this with cmake: [...] Imported target "Boost::program_options" includes non-existent path "/include" in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include: [...] Can someone reproduce the issue or suggest a fix? Best wishes and TIA, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * SoundCloud: https://soundcloud.com/jeanette_c * Twitter: https://twitter.com/jeanette_c_s * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c There's a girl in the mirror I wonder who she is Sometimes I think I know her Sometimes I really wish I did <3 (Britney Spears)

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[release] 1.73.0 closed for Beta
by Marshall Clow 09 Apr '20

09 Apr '20

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_73_0.q… > Thanks, -- The Boost Release Team

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[Boost.Test] linking with shared lib (cannot find main)
by Andrew McFarlane 06 Apr '20

06 Apr '20

Hi all, I have been using Boost.Test for about a month now. Big fan so far, except for the atrocious compilation times, hence why I am moving toward using the shared library. using b2 to build and install Boost.Test's libs was simple enough, though after making the noted changes here: https://www.boost.org/doc/libs/1_72_0/libs/test/doc/html/boost_test/adv_sce… to customize the module's entry point, g++ cannot find the main executable: Undefined symbols for architecture x86_64: "_main", referenced from: implicit entry/start for main executable ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [Guest_T] Error 1 I tried digging through the docs for more information, but I came up short. For more context, I have written unit tests for each of my classes. For example, if my classes were A, B, and C, I would have A_T.cpp, B_T.cpp, and C_T.cpp for unit tests. - Should each of the unit tests have their own main() function? (I would think not..) - If not, how do I instruct g++ to first compile main.cpp before attempting to compile anything else? If you are curious, here are the contents of my Makefile: PROG := main CC := g++ SDIR := ../src PKG_DIRS := $(shell ls $(SDIR)) CXXFLAGS = -v -Wall -std=c++11 -I$(SDIR_TEST) \ $(addprefix -I$(SDIR)/,$(PKG_DIRS)) -I$(BOOST_ROOT) \ -L$(BOOST_LIBS) -Wl,-rpath,$(BOOST_LIBS) -lboost_unit_test_framework ODIR_TEST = ./bin SDIR_TEST = ./src OUTDIR = ./execs ODIR = ../sim/bin TEST_EXEC_NAMES = $(notdir $(basename $(wildcard $(SDIR_TEST)/*.cpp))) $(OUTDIR)/$(PROG) : $(SDIR_TEST)/main.cpp $(CC) $(CXXFLAGS) -o $@ $< $(OUTDIR)/$(PROG) : $(TEST_EXEC_NAMES) $(CC) $(CXXFLAGS) -o $@ $^ % : $(SDIR_TEST)/%.cpp $(CC) $(CXXFLAGS) -o $(OUTDIR)/$@ $^ >From what I can tell, g++ is failing to find the main the executable because it is attempting to compile one of my unit test files first. This may or may not be the case; either way, I would appreciate some help or direction as to what I should read to learn more about this. Let me know if you need more info. Thanks in advance. - AJ

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[Boost.Test] duplicate symbol '_main' (manual test registration)
by Andrew McFarlane 06 Apr '20

06 Apr '20

Hi all, As the subject line suggests, I am attempting to manually employ a master test suite that registers several sub test suites. - Each subtest suite has its own header and translation unit. - Each header has a public "init_test_suite()" method and several private "test_case<number>()" methods, all of which are declared static. The public method creates a test suite, adds all the test cases for that translation unit, and adds the suite to the master test suite. This method is intended to be called from main.cpp. Here is a simplified version of my main.cpp: #define BOOST_TEST_DYN_LINK #define BOOST_TEST_NO_MAIN #include <boost/test/unit_test.hpp> #include "A.h" #include "B_T.h" #include "C_T.h" bool register_test_suites() { A_T::init_test_suite(); B_T::init_test_suite(); C_T::init_test_suite(); return 0; } int main(int argc, char *argv[], char *envp[]) { return boost::unit_test::unit_test_main(&register_test_suites, argc, argv); } Here's the issue. Despite the fact that I have defined BOOST_TEST_NO_MAIN, it appears that my compiler is still generating 2 objects files for the main executable entry: duplicate symbol 'register_test_suites()' in: /var/folders/bc/v2yqpsf96kn31tx8ybvy9gyw0000gn/T/main-58c6b3.o bin/main.o duplicate symbol '_main' in: /var/folders/bc/v2yqpsf96kn31tx8ybvy9gyw0000gn/T/main-58c6b3.o bin/main.o ld: 2 duplicate symbols for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [execs/main] Error 1 As you might be wondering, all of my test translation units define BOOST_TEST_DYN_LINK, and none of them define BOOST_TEST_MODULE, as the documentation suggests. I tried removing BOOST_TEST_NO_MAIN from main.cpp but that did not appear to do anything. I also tried removing the static and shared Boost.Unit lib files from my stage/lib directory and rebuilding only the shared version, and that did not work either. Also not that my g++ command does have the expected -L and -l flags for linking with Boost.Test: -L/usr/local/boost_1_72_0/stage/lib -lboost_unit_test_framework I am lost here. No idea why main() is being defined twice. Thanks in advance. - AJ

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BOOST_TEST_STRING_VIEW
by Leo Carreon 06 Apr '20

06 Apr '20

Hi Boost Users, Does anyone know what BOOST_TEST_STRING_VIEW is for? Kind regards, Leo

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Issue upgrading boost from 1.5.6 to 1.7.2
by Luke Knoble 06 Apr '20

06 Apr '20

Ello!! This is my first time using a mail group! I'm using Visual Studio 2019. My error is this: error C2977: 'boost::mpl::map': too many template arguments I'm using about 139 arguments for this map. Do I need to rebuild Boost with some custom flag? Thanks, Luke

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boost range dynamic joined_range
by Lars Sunde 06 Apr '20

06 Apr '20

Hello, How can I create a Boost Range for multiple vectors without setting any limitation to the number of vector at compile time? Using Boost 1.70 and it is not an option to store all data in one vector. The following code compile on Visual Studio 2017 and will output the number 1 to 9. However, this code is compiled to support 3 vectors inside the foo struct. In order to support 4 vectors I would need to re-compile the code. The number of vectors is only known at runtime. How can this code be improved to support a dynamic number of vectors ? #include <iostream> #include <vector> #include <boost/range.hpp> #include <boost/range/join.hpp> struct foo { typedef boost::range::joined_range< boost::range::joined_range< std::vector<int>, std::vector<int>>, std::vector<int>> range; std::vector<std::vector<int>> vec; foo() { vec = { {1,2,3}, {4,5,6}, {7,8,9} }; } range my_range() { auto range1 = boost::join(vec[0], vec[1]); return boost::join(range1, vec[2]); } }; int main() { foo f1; for (auto item : f1.my_range()) std::cout << item << " "; return 0; } Appreciate any input. Kind regards, Lars

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[type-erasure?] callable configurable type-erasure
by Igor R 05 Apr '20

05 Apr '20

Hi, In my project I need a callable type-erasure - just like std::function/boost::function, but with a *configurable* small-object optimization (I will use it in a context where dynamic allocation is highly discouraged, so I'm going to make relatively big "static" holder). Is it possible to use TypeErasure library this way? Or maybe we have some other facilities in Boost that could be useful for this purpose? Thanks.

1 1

asio and custom socket implementation
by Stanislav Zaikin 03 Apr '20

03 Apr '20

Hello! I have a custom network stack (it processed packets in userspace) which exposed some functions in C. It has its own listen, bind, accept functions and many other, and furthermore even custom epoll, select and poll. I want to expand asio in some away, just to support my application with this custom network stack. But I'm a bit confused how I can do it. Should I write my own basic io class? Or should I write custom socket service class like (reactive_socket_service_base)? And is it possible to use basic tcp classes (with any of them)? If there are any examples in open source please let me know. -- Best regards Stanislav Zaikin

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Boost download links seems to be down
by andrews＠brutsoft.com 28 Mar '20

28 Mar '20

I'm getting 403 when trying to download boost from links at https://www.boost.org/users/history/version_1_72_0.html (https://www.boost.org/users/history/version_1_72_0.html) Is it just me? If not, how do we get this fixed? Thanks, Andrew

3 3

[program_options] cmake error
by Jeanette C. 27 Mar '20

27 Mar '20

Hey hey, I get a cmake error about a non-existent directory from boost::program_options, namely /include . It only happens with the program_options library. Other libs included in the project are date_time, filesystem and system. A quick peak at /lib/cmake/boost_program_options-1.72.0/boost_program_options-config.cmake compared to the same file from date_time didn't give me any obvious hint though. But I'm not very familiar with cmake. The cmake line to find these Boost packages is this: find_package(Boost 1.58 REQUIRED COMPONENTS program_options filesystem date_time system) Here's the error message from my program's cmake: [...] Imported target "Boost::program_options" includes non-existent path "/include" in its INTERFACE_INCLUDE_DIRECTORIES. Possible reasons include: [...] Can someone reproduce the issue or suggest a fix? Best wishes and TIA, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * SoundCloud: https://soundcloud.com/jeanette_c * Twitter: https://twitter.com/jeanette_c_s * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c There's a girl in the mirror I wonder who she is Sometimes I think I know her Sometimes I really wish I did <3 (Britney Spears)

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[Boost.Graph] is it still active?
by Omar Khaled 27 Mar '20

27 Mar '20

Hey, I was wondering if the library is still active and open for refinements? I see that last **real** code written in it was committed to github repo from a year or so? are the maintainer still active? Thanks !!!

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