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Boost 1.74: Coroutines2 on MSVC 2019 / C++20
by Daniel Petrovic 29 Oct '20

29 Oct '20

Using Boost 1.74. By using coroutines 2 on MSVC 2019 (v16.7.7) with C++20 there is a compilation issue regarding result_of which is replaced by invoke_result in C++20. Is there already some patch for 1.74 or maybe work in progress for 1.75 regarding this issue ? Regards Daniel

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[Signals2] Deprecated header warning VS2017 Boost 1.74
by Peter Barker 27 Oct '20

27 Oct '20

Hi, Just upgraded to Boost 1.74 from Boost 1.71. I'm getting a warning: c:\releases\lib\boost\boost_1_74_0\include\boost\function_output_iterator.hpp(14): note: This header is deprecated. Use <boost/iterator/function_output_iterator.hpp> instead. from this MWE: #include <boost/signals2/signal.hpp> int main() { } I'll have to #define BOOST_ALLOW_DEPRECATED_HEADERS I guess, but I'm surprised Boost libraries are using deprecated Boost headers. Regards, Pete

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A Newbie Boost.Build with Variants Question
by Ryan Heniser 24 Oct '20

24 Oct '20

Hi, I am building Boost 1.61 (we need this old version for other libraries) for the first time at work with Boost.Build (b2). I have successfully built Boost (using b2) for gcc 4.8. If I want to add one or more variants (for example using gcc 6.3), where should I put the Boost header’s include directory? Should one go inside each variant or should just one go at the root directory containing the variant directories? Kind regards, Ryan

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[Newbie][Intrusive] - Beginners question
by Gaier, Bjoern 22 Oct '20

22 Oct '20

Hey everybody, I looked into the boost intrusive container and played around with it a bit. I tried the following code: struct animal : public boost::intrusive::list_base_hook<> { std::string name; int legs; animal(std::string n, int l) : name{std::move(n)}, legs{l} {} }; int main(int argc, char **argv) { std::vector<animal> test; boost::intrusive::list<animal> wuff; for(int n = 0; n < 5; n++) { test.push_back(animal("Katze", 4)); } for(int n = 0; n < 5; n++) { wuff.push_back(test[n]); } for(int n = 0; n < 15; n++) { wuff.push_back(test[n]); } for(auto elem : wuff) { printf("%s\n", elem.name.c_str()); } } This code does crash! I guess this is because "test" relocated the memory and therefor "wuff" lost its references. I would expect the same result if I would have a std::list with pointers to animal structures - this is why I wonder what the benefit of an intrusive container is compared to the same container with just pointers in it. Hope someone can explain me this! Thank you in advance and kind greetings Björn Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816, USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Junichi Tajika, Ergin Cansiz.

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Does boost promise/future support corroutines?
by David Frank 19 Oct '20

19 Oct '20

Hi, Does boost promise/future support coroutines? For example, the get call only block the running coroutine, instead of the whole thread? Thanks,David

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Boost.MSM: Problem with defered events
by Georg Gast 16 Oct '20

16 Oct '20

Dear Boost users, i am currently writing a driver for the ADS1256 chip with Boost.MSM. Yes, there are other drivers. I do this for training and fun. During the startup phase i need to defer the requests from the user as the SPI bus is not yet available. To model the behaviour the most correct, i tried to model it with MSM. In the transition table, i use the "Defer" action to defer these events. In my Idle state, after the startup phase, there is a transition with this defered event going to the "work" states. In the debugger i can see, that the defered_event_queue holds one defered event and it is of my type but it is not processed. I did use boost 1.67.0 (from debian buster ) and also 1.74.0 (self compiled) to test this. My program can be also compiled under Windows and VS2019 as i handled the hardware interfacing with a abstract class. It works under Windows and 1.74.0. With VS2017 and 1.67.0 it also does not work. Under Linux and gcc it always stops at the Idle state where i wait for the defered event. At the end is my transition table. Any ideas are welcome! Georg // clang-format off struct transition_table : mpl::vector< // +----------------+-------------------+----------------+---------------------------+----------------------+ // Region 0 // +----------------+-------------------+----------------+---------------------------+----------------------+ // Start Event Next Action Guard // +----------------+-------------------+----------------+---------------------------+----------------------+ Row < NotIntialized , ev_Init , WaitDRDYID , none , none >, Row < WaitDRDYID , ev_CheckFlags , ReadID , none , IsDrdy0 >, Row < ReadID , ev_CheckFlags , none , none , none >, Row < ReadID , Spi::Reply , ReadIDFailed , none , IsIDNotOk >, Row < ReadID , Spi::Reply , Idle , none , IsIDOk >, // during the startup phase these event must be defered Row < NotIntialized , ev_MultiStart , none , Defer , none >, Row < WaitDRDYID , ev_MultiStart , none , Defer , none >, Row < ReadID , ev_MultiStart , none , Defer , none >, // +----------------+-------------------+----------------+---------------------------+----------------------+ Row < Idle , ev_CheckFlags , none , none , none >, Row < Idle , ev_MultiStart , MConfigWaitDRDY, none , none >, // +----------------+-------------------+----------------+---------------------------+----------------------+ Row < MConfigWaitDRDY, ev_CheckFlags , MSwitchConfig , none , IsDrdy0 >, Row < MSwitchConfig , ev_CheckFlags , none , none , none >, Row < MSwitchConfig , Spi::Reply , MMuxWaitDRDY , none , IsECNotFailed >, Row < MMuxWaitDRDY , ev_CheckFlags , MSwitchMux , none , IsDrdy0 >, Row < MSwitchMux , ev_CheckFlags , none , none , none >, Row < MSwitchMux , Spi::Reply , MSync , none , IsECNotFailed >, Row < MSync , Spi::Reply , MDataWaitDRDY , none , IsECNotFailed >, Row < MDataWaitDRDY , ev_CheckFlags , MReadData , none , IsDrdy0 >, Row < MReadData , ev_CheckFlags , none , none , none >, Row < MReadData , Spi::Reply , Idle , WorkDone , IsWorkDone >, Row < MReadData , Spi::Reply , MMuxWaitDRDY , RemoveDoneWork , IsStillWorkTodo >, // +----------------+-------------------+----------------+---------------------------+----------------------+ // Region 1 // +----------------+-------------------+----------------+---------------------------+----------------------+ Row < DrdyUndefined , ev_DRDY_0 , Drdy0 , none , none >, Row < DrdyUndefined , ev_DRDY_1 , Drdy1 , none , none >, Row < Drdy0 , ev_DRDY_0 , none , none , none >, Row < Drdy0 , ev_DRDY_1 , Drdy1 , none , none >, Row < Drdy1 , ev_DRDY_0 , Drdy0 , none , none >, Row < Drdy1 , ev_DRDY_1 , none , none , none >, // +----------------+-------------------+----------------+---------------------------+----------------------+ // Region 2 // +----------------+-------------------+----------------+---------------------------+----------------------+ // Start Event Next Action Guard // +----------------+-------------------+----------------+---------------------------+----------------------+ Row < AllOk , Spi::Reply , ErrorMode , none , IsECFailed > // +----------------+-------------------+----------------+---------------------------+----------------------+ > {}; // clang-format on

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[Circular Buffer] Why doesn't have “emplace” interface?
by Марсель Галимуллин 16 Oct '20

16 Oct '20

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Boost configuration for VS Code / MacOS X Catalina
by Stefano Gragnani 12 Oct '20

12 Oct '20

Hi, how should i configure vs code to use Boost? I tried to compile the following example: #include <iostream> #include <boost/multiprecision/float128.hpp> #include <boost/math/special_functions/gamma.hpp> int main() { using namespace boost::multiprecision; // Operations at 128-bit precision and full numeric_limits support: float128 b = 2; // There are 113-bits of precision: std::cout << std::numeric_limits<float128>::digits << std::endl; // Or 34 decimal places: std::cout << std::numeric_limits<float128>::digits10 << std::endl; // We can use any C++ std lib function, lets print all the digits as well: std::cout << std::setprecision(std::numeric_limits<float128>::max_digits10) << log(b) << std::endl; // print log(2) = 0.693147180559945309417232121458176575 // We can also use any function from Boost.Math: std::cout << boost::math::tgamma(b) << std::endl; // And since we have an extended exponent range we can generate some really large // numbers here (4.02387260077093773543702433923004111e+2564): std::cout << boost::math::tgamma(float128(1000)) << std::endl; // // We can declare constants using GCC or Intel's native types, and the Q suffix, // these can be declared constexpr if required: constexpr float128 pi = 3.1415926535897932384626433832795028841971693993751058Q; return 0; } but that's what I get: Executing task: g++-10 -g -std=c++17 '-fext-numeric-literals' main.cpp -L/usr/local/Cellar/gcc/10.2.0/lib/gcc/10/ -lquadmath -o main.out < main.cpp:2:10: fatal error: boost/multiprecision/float128.hpp: No such file or directory 2 | #include <boost/multiprecision/float128.hpp> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ compilation terminated. The terminal process "/bin/zsh '-c', 'g++-10 -g -std=c++17 '-fext-numeric-literals' main.cpp -L/usr/local/Cellar/gcc/10.2.0/lib/gcc/10/ -lquadmath -o main.out'" failed to launch (exit code: 1). My task.json is: { // See https://go.microsoft.com/fwlink/?LinkId=733558 <https://go.microsoft.com/fwlink/?LinkId=733558> // for the documentation about the tasks.json format "version": "2.0.0", "tasks": [ { "label": "Build with g++ 10", "type": "shell", "command": "g++-10", "args": [ "-g", "-std=c++17", "'-fext-numeric-literals'", "main.cpp", "-L/usr/local/Cellar/gcc/10.2.0/lib/gcc/10/", "-lquadmath", "-o", "main.out" ], "group": { "kind": "build", "isDefault": true } }, { "label": "Build with Intel ICC", "type": "shell", "command": "icc", "args": [ "-g", "-std=c++17", "main.cpp", "-o", "main.out" ], "group": { "kind": "build", "isDefault": true } }, { "label": "Run Project", "type": "shell", "command": "./main.out", "group": { "kind": "build", "isDefault": true } } ] } And my c_cpp_properties.json is: { "configurations": [ { "name": "Mac", "includePath": [ "${workspaceFolder}/**", "/usr/local/Cellar/boost/1.73.0/include/**" ], "defines": [], "macFrameworkPath": [], "compilerPath": "/usr/local/bin/g++-10", "cStandard": "gnu18", "cppStandard": "gnu++14", "intelliSenseMode": "gcc-x64" } ], "version": 4 } Thanks Stefano Gragnani

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A question about boost::uuid
by Shishir Pandey 10 Oct '20

10 Oct '20

Hi all, I have been trying to figure out how to use murmurhash3 with boost::uuid. Looking at the documentation it is not entirely clear to me if a class implementing murmurhash3 that provides the interface defined by NameHashProvider would be sufficient. If yes, would creating a wrapper over the following implementation work? https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp Can anyone direct me to some similar implementation perhaps not of using murmurhash3 but of using any other algorithms? Regards, Shishir Pandey -- Necessity is not an established fact, but an interpretation. - Friedrich Wilhelm Nietzsche

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Re: [Boost-users] [Boost-announce] [PFR][review] Result
by Antony Polukhin 09 Oct '20

09 Oct '20

On Thu, Oct 8, 2020, 13:51 Benedek Thaler via Boost-announce < boost-announce(a)lists.boost.org> wrote: <...> > Benedek > review wizard > Many thanks for beeng the review manager! >

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Re: [Boost-users] [Boost-announce] [FPR] Review of FPR starts Today: Sept 28 - Oct 7
by Nat Goodspeed 05 Oct '20

05 Oct '20

On Mon, Sep 28, 2020 at 1:15 PM Benedek Thaler via Boost-announce < boost-announce(a)lists.boost.org> wrote: - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? > I have read only the announcement email, but it prompts a very interesting question: does the FPR library facilitate integration with Boost.Serialization? If not yet, how hard would it be to improve the interoperability of those two libraries? If the FPR documentation already addresses this point, a terse reply to that effect will suffice.

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improve TypeTraits
by Gero Peterhoff 04 Oct '20

04 Oct '20

Hello John, you have probably already read that I think some new TypeTraits are useful. Here are the details: a) very useful: precise type classification - this is the basis of every abstraction and should definitely be implemented - is_character: contains only characters (char32/16/8_t, wchar_t, char); is_un/signed_character - is_integer: contains only integers and no characters and no bool (u/int8..X_t); is_un/signed_integer - is_logic: contains only logical types (bool and boost::tribool, *)) - is_string: contains everything that can be used as a string, but needs these specializations: 1) is_bounded_string (similar to is_bounded_array) 2) is_unbounded_string (similar to is_unbounded_array) 3) is_static_string (for boost::basic_static_string) 4) is_string_ref (for boost::basic_string ref) 5) is_string_view (for std::basic_string_view) 6) is_string_class (for std::basic_string) - character_of: the underlying character type based on is_string b) very useful - remove_cv_ptr (similar to remove_cv_ref) - make_same_signed (similar to make_un/signed): changes the sign depending on a type - conditional_signed: changes the sign depending on a truth value - is_same_signed: same sign c) also makes sense - is_tuple - is_rational (similar to boost::is_complex) - is_binary: if base==2 (numeric_limits::radix==2) - is_decimal: if base==10 (numeric_limits::radix==10) d) - is_native: a type is natively available on the platform (e.g. int64_t: Linux32:false, Linux64:true; float80_t: x86:true, else:false) - is_vectorisable: a type can be vectorized natively on the platform - there are basic SSE/AVX/SVE/... functions However, I have a problem: boost/std::is_integral contain bool. Perhaps you can do that like this, but it leads to problems with is_arithmetic, since is_arithmetic is based on is_integral and thus contains bool. I think the point of is_arithmetic is to be able to calculate numerically with the type - so the scenarios are not useful: abs(bool), sin/cos/...(bool), etc. The same applies to characters. There are two possible solutions: - redefine is_arithmetic -> is_integer || is_floating_point - a new TypeTrait is_numeric (e.g.) -> is_integer || is_floating_point There are some differences between boost- and std-TypeTraits. Can you please include that in the documentation? Furthermore there seem to be errors with char8_t, e.g. boost::is_unsigned<char8_t> -> false, std::is_unsigned<char8_t> -> true (correct). Summary With these measures, a large number of template functions/classes can then be tailored precisely to the application and incorrect use can be prevented. regards Gero *) I've written a couple of classes for logic: bool3_t (a modern variant of boost::tribool), bool4_t (http://www.filosofia.unimi.it/dagostino/wp-content/uploads/2017/05/Belnap.p…) and bool2_t (for completeness)

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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.

2 1

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

1 1

[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?

1 0

[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

1 0

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

5 7

[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.

2 1

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

4 5

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

1 0

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

1 0

[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

3 2

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

3 3

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?

1 0

[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

4 4

[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

5 6

[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

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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

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[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.

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