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[fiber][asio] Problem running http://www.boost.org/doc/libs/1_65_0/libs/fiber/examples/asio/autoecho.cpp
by Mark Hieber 24 Aug '17

24 Aug '17

Hi, I am using cmake 3.9.1 and Boost 1.65.0. I have downloaded the autoecho.cpp file and the corresponding yield.hpp, detail/yield.hpp and round_robin.hpp from http://www.boost.org/doc/libs/1_65_0/libs/fiber/examples/asio. When I run my program (just these 4 files, with no modifications), I get this output: Thread A: started Thread A: A0: echo-server started Segmentation fault Using print statements the seg-fault happens in the io_svc->run(); call. If anyone can help me with this, I would appreciate it. BTW, I am running on Ubuntu 16.04.3 LTS Thanks, Mark

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Portable file I/O with system error codes support
by Oleg Andriyanov 23 Aug '17

23 Aug '17

Hi, I'm looking for a portable way to open a file, read some data from it, and do a proper error reporting in case of error. Apparently std::fstream is not suitable for this task because it does not provide means to retrieve original error code or even some human readable description of what went wrong (checking errno does not count since the standard does not guarantee it is set by any functions in std::fstream). I'm wondering if boost::iostreams can do that, but I've found nothing this far that could help in getting the error code. I've also tried boost::filesystem::fstream, but no luck. Users of large frameworks like Qt have advantage of their portable wrappers for file I/O like QFile. Are there any means in Boost which provide similar functionality? Related StackOverflow question: https://stackoverflow.com/questions/45840686/portable-way-to-read-a-file-in… Thanks.

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[release] Boost 1.65.0
by Daniel James 21 Aug '17

21 Aug '17

Release 1.65.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains two new libraries and numerous enhancements and bug fixes for existing libraries. For details, including download links, see <http://www.boost.org/users/history/version_1_65_0.html> You can also download directly from: <https://dl.bintray.com/boostorg/release/1.65.0/> 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 Vladimir Prus, Rene Rivera, Marshall Clow, Eric Niebler, Daniel James, Beman Dawes

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Is there a C++ implementation for numerical quadrature/cubature?
by Easior Lars 20 Aug '17

20 Aug '17

Hi, all in the list! I need some functions to handle numerical quadrature/cubature in C++. I found that only few packages, e.g. GSL, could do this end. However, those ones are not pure C++ implementations. Although, odeint package in Boost can partially satisfy my need. I want to know whether there is a C++ implementation for numerical quadrature/cubature in Boost. Any suggestion? -- Best wishes, Easior ------ "It was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to heaven, we were all going direct the other way - in short, the period was so far like the present period, that some of its noisiest authorities insisted on its being received, for good or for evil, in the superlative degree of comparison only." TALES OF TWO CITIES, by Charles Dickens

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[Boost][Container] Why is flat_set default constructor explicit?
by dariomt＠gmail.com 18 Aug '17

18 Aug '17

Hi all, I just found out that all Boost.Container default constructors are implicit (just as I would expect) except for flat_set. Quoting from [1]: explicit flat_set() noexcept(/*snip*/); Effects: Default constructs an empty container. Why is flat_set different than the other containers? Is this an oversight? FWIW this issue is breaking my C++14 code (for both clang and gcc) when switching from std::set to boost::container::flat_set, minimal repro follows: #include <boost/container/flat_set.hpp> #include <set> #ifndef USE_STD_SET using S = boost::container::flat_set<int>; #else using S = std::set<int>; #endif struct A { int i; S s; }; int main() { A a1; // OK A a2 {0, {{}} }; // OK A b1 {}; // FAILS A b2 {0}; // FAILS A b3 {0, {}}; // FAILS } A f() { return {}; // FAILS } Using Bost 1.64.0 in case that matters. Any help appreciated. [1] http://www.boost.org/doc/libs/1_64_0/doc/html/boost/container/flat_set.html…

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Re: [Boost-users] Boost 1.65.0 Release Candidate 4
by Marshall Clow 17 Aug '17

17 Aug '17

On Wed, Aug 16, 2017 at 8:33 PM, Marshall Clow <mclow.lists(a)gmail.com> wrote: > The fourth (and hopefully final) release candidates for the 1.65.0 release > are now available at: > > https://dl.bintray.com/boostorg/release/1.65.0/source/ > [snippage] 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. * Builds successfully with Apple Clang [Apple LLVM version 8.0.0 (clang-800.0.42.1)] with C++03/11/14/1z * Builds successfully with Clang Trunk [clang version 6.0.0 (trunk 310587)] with C++03/11/14 * Built successfully with Clang Trunk [clang version 6.0.0 (trunk 310587)] with C++1z except for Boost.Locale. -- Marshall

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Boost 1.65.0 Release Candidate 4
by Marshall Clow 17 Aug '17

17 Aug '17

The fourth (and hopefully final) release candidates for the 1.65.0 release are now available at: https://dl.bintray.com/boostorg/release/1.65.0/source/ [ Note: The RC1s/RC2s/RC3s are in that directory, too - make sure you get the right files! ] Changes since RC3: * Fix a bug in Boost.Thread where timed waits were waiting for a very long time. Changes since RC2: * Fix a crashing bug in Boost.ASIO * Fix a compilation error when including both <boost/math_fwd.hpp> and <boost/math/common_factor_ct.hpp> * An update to Boost.Spirit to fix compilation errors on Mac OS with -std=c++17 Changes since RC1: * An update to Boost.Config so that the flags BOOST_NO_CXX98_RANDOM_SHUFFLE and BOOST_NO_CXX98_BINDERS are now set appropriately for libc++. (This fixes the compilation errors for Boost.Test) * An update to Boost.Fiber to fix compilation errors * An update to Boost.Wave to fix compilation errors on Mac OS with -std=c++17 The SHA256 checksums are as follows: 5d255d1ff8460d52dffcf9a9b55d908ae704027a66c590ec774096effaea26c1 boost_1_65_0_rc4.7z 911602d830ea5d16483d1e565b9859d120d03f2e5176017226ef391eb9d17fc8 boost_1_65_0_rc4.tar.bz2 369e06dc787d32b0fbaae020f33d814c9e7b77263acb859776968e623035f760 boost_1_65_0_rc4.tar.gz a9c6b8346b05ea43ac4278e80036a9e956ea99fc61f0b7f55469471af2df934c boost_1_65_0_rc4.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. Thanks! -- The release managers

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Where we are 1.65.0
by Marshall Clow 17 Aug '17

17 Aug '17

RC1 came out on Monday, and it had some problems. Specifically: * Some libraries didn't build with ToT clang/libc++ (Locale, Wave and Test) This is because in C++17, some deprecated library features have been removed. [bind1st, mem_fun, auto_ptr, random_shuffle, etc ] Boost.Config has support for these removals, but this was ... incomplete. [ This is on me; I did the partial job of adding these to Config's libc++ support a while back ] Normally, I would be tempted to say "Well, clang 5 is not shipping yet, and so we can put this off until 1.66.0". But both clang 5 and C++17 are imminent (they will both happen well before the 1.66 release, and so I think we should fix this now. Also, a future version of MSVC will have the same library issues. So I have committed a fix for Boost.Config that fixes the Boost.Test issues. Hartmut has fixed most of the Boost.Wave issues. Artymom has a fix for Boost.Locale. Windows/MSVC builds look good across the board. * Boost.Fiber fails to build on Mac OS with anything other than -std=c++03. There is a fix in develop for this; but there's still a bunch of tests failing. * There's a problem from the beta in Boost.Math. The regression regarding boost/math/common_factor_ct.hpp (vs > math_fwd.hpp) seems to be still there. (For details please see the > original mail and replies: > https://lists.boost.org/Archives/boost/2017/07/237452.php) > What I presume is the fix (https://github.com/boostorg/math/pull/75) was > merged into develop about 12 hours ago, some automatic CI tests still > running. * There's a problem with ScopeExit and Visual C++ 2017 With Visual C++ 2017 and /permissive-, ScopeExit is still broken, for which > there's an open PR: > https://github.com/boostorg/scope_exit/pull/3 > Looks good otherwise on MSVC 14.11, tested with /std=cpplatest and > _HAS_AUTO_PTR_ETC=1, targeting Windows 10 and XP, 32 bit and 64 bit, built > as static libraries. >

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constructing rationals from mpfr_floats [multiprecision]
by Dani Brake 16 Aug '17

16 Aug '17

Hi, 1) I am getting signaling due to division by 0. The following lines are faulty: mpfr_float p("1.1"); mpq_rational q(p); signal: integer divide by zero; whereas this succeeds: mpq_rational q(1.1); any one seen this before? i'm on compiler Apple LLVM version 8.0.0 (clang-800.0.38) ,with homebrew-provided boost 1.64, mpfr 3.1.5, gmp 6.1.2. -- 2) I also expected to be able to construct rationals as mpq_rational q("1.1") but it fails to parse using the built-in constructor. i mean, i understand why (1.1 isn't a rational), but given that i can construct a rational from a double, i figured that i'd get something reasonable from "1.1", namely 11/10. -- thanks! dani brake university of wisconsin eau claire ps i am not disabling mixed double-multiprecision arithmetic in this scenario, in case you have been reading my other questions this last week

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Re: [Boost-users] deleting operators to forbid mixed arithmetic? [multiprecision]
by Dani Brake 16 Aug '17

16 Aug '17

Paul and John, Putting a macro bracket around this might make it generally useful, perhaps > something like: > > #ifdef BOOST_MULTIPRECISION_NO_DOUBLE_OPS (BUILTIN_OPS would include > float and long double?) > > … > > template <class Backend> > struct is_compatible_arithmetic_type<double, number<Backend> > : public > mpl::false_ {}; > > say > #endif > > If you find this useful, you could create a GIT Pull Request, or just > email the file changed. You won’t be the only one J. Defining the macro > BOOST_MULTIPRECISION_NO_DOUBLE_OPS could be a way to detect dodgy > conversions that need to be changed to keep full precision. I implemented this in my codebase, and had few ill effects. Some unexpected conversions, but I did find this disabling very useful. Wrapping it in a macro bracket and making it officially supported would be fabulous. I think it should go in number_base.hpp at line 110 or so. If we wanted to make it robust and thorough, I think we need to consider turning off implicit constructors from disabled types, too. I believe that what we have so far only disables arithmetic. Dani

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