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Re: [boost] Boost 1.57 hot-out-of-Git fails to compile for Windows Phone
by Moshe Rubin 04 Dec '14

04 Dec '14

To simplify reproducing the problem, run "b2" rather than the more complicated "b2 toolset=msvc-12.0 ... stage", same problem occurs. Bottom line: a clean clone of Boost 1.57, with the command "b2", fails with the same error. Moshe

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Boost 1.57 hot-out-of-Git fails to compile for Windows Phone
by Moshe Rubin 04 Dec '14

04 Dec '14

I cloned Boost 1.57 from GitHub, intending to run b2 with the appropriate options to build libraries for Windows Phone. I understand that Steven Gates's pull requests for Windows Phone have already been merged in. Running the appropriate "b2" command fails with an error message. Can you help? Here are the steps I took (I'm running MSVC 2013, so I've got all required libs etc.): (*) Clone Boost 1.57 from GitHub (*) cd to the boost folder (*) Execute "bootstrap" (*) Execute "b2 headers" (*) Execute "b2 toolset=msvc-12.0 windows-api=phone architecture=arm link=static variant=debug debug-symbols=on debug-store=database stage" I get the following output: ============================================================================= Performing configuration checks - symlinks supported : no (cached) - junctions supported : yes (cached) - hardlinks supported : yes (cached) - 32-bit : yes - has_icu builds : no warning: Graph library does not contain MPI-based parallel components. note: to enable them, add "using mpi ;" to your user-config.jam - zlib : no - iconv (libc) : no - iconv (separate) : no - icu : no - icu (lib64) : no - message-compiler : yes - gcc visibility : no - long double support : no warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. error: Name clash for '<pstage\lib>libboost_system-vc120-mt-gd-1_58.lib' error: error: Tried to build the target twice, with property sets having error: these incompabile properties: error: error: - <warnings>all error: - <address-model>32 <warnings>on error: error: Please make sure to have consistent requirements for these error: properties everywhere in your project, especially for install error: targets. ============================================================================= When I examine the generated file bin.v2\project-cache.jam, I see that "set junctions" and "set hardlinks" commands are duplicated for "<windows-api>phone", where the only difference between them is "<warnings>on" and "<warnings>all", possibly causing the error messages: <snippet> set "symlinks supported-<abi>ms-<architecture>arm...-<warnings>on-<windows-api>phone" : "false" ; set "junctions supported-<abi>ms-<architecture>arm...-<warnings>on-<windows-api>phone" : "true" ; set "hardlinks supported-<abi>ms-<architecture>arm...-<warnings>on-<windows-api>phone" : "true" ; set "symlinks supported-<abi>ms-<architecture>arm...-<warnings>all-<windows-api>phone" : "false" ; set "junctions supported-<abi>ms-<architecture>arm...-<warnings>all-<windows-api>phone" : "true" ; set "hardlinks supported-<abi>ms-<architecture>arm...-<warnings>all-<windows-api>phone" : "true" ; </snippet> (1) Why are the first three statements duplicated for windows-api=phone? (2) Why does <warnings> differ between them? (3) Where in Boost.Build is this generated? (4) How can I solve the problem and move forward? Many thanks in advance, Moshe

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[range] insert not returning value for associative containers without 'before' iterator
by Adam D. Walling 04 Dec '14

04 Dec '14

The modification to boost/range/algorithm_ext/insert.hpp added an insert overload which does not take a 'before' iterator, but the implementation fails to return the Container passed in as it is supposed to. This causes the compiler to fail (eg with error C4716 must return a value in MSVC). https://svn.boost.org/trac/boost/ticket/6726 Fix is to simply add 'return on': template< class Container, class Range > inline Container& insert( Container& on, const Range& from ) { BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<Container> )); BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<Range> )); on.insert(boost::begin(from), boost::end(from)); + return on; } Admittedly I am uncertain how bugs are being tracked now; is trac still being used or something on github? Thanks, Adam D. Walling

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[VC++ 14.0 preview] New failures in develop regression tests
by Beman Dawes 03 Dec '14

03 Dec '14

At my request, Tom Kent has kindly added VC++ 14.0 (toolset msvc-14.0) to his develop branch tests. See http://www.boost.org/development/tests/develop/developer/summary.html rightmost column. This compiler is available as part of the Visual Studio 2015 Preview. See http://www.visualstudio.com/en-us/downloads/visual-studio-2015-downloads-vs… Several libraries are showing new test failures. Please check out the test results to see if your library has started to fail. If it is your problem, fix it or at least create a ticket for yourself:-) If it is a Microsoft problem, consider submitting a bug report and posting a notice on the Boost list so that other developers are aware of the problem. Also post a link to the bug report on https://connect.microsoft.com Knowing the Microsoft Connect URL for the bug report lets other boosters up vote the importance of the issue. This is known to have at least some influence on the priority given the bug report, and that means faster fixes for the bugs boosters care about. Thanks, --Beman

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GDB-like debugger for template metaprograms
by Abel Sinkovics 03 Dec '14

03 Dec '14

Hi, Metashell 2.0.0 has a template metaprogram debugger with a GDB-like interface (thanks to András Kucsma), which can be useful for Boost developers. It can show you how your metaprogram is executed step-by-step. You can set breakpoints, step into or over the metafunction calls and inspect the "template metaprogramming stack trace" at any point during this: the chain of recursive template instantiations that lead to that point. Here is an example: > #include <boost/mpl/transform.hpp> > #include <boost/mpl/vector_c.hpp> > #include <boost/mpl/plus.hpp> > #include <boost/mpl/lambda.hpp> > #include <boost/mpl/int.hpp> > using namespace boost::mpl; > #msh mdb transform<vector_c<int, 1, 2, 3, 4, 5>, plus<_1, int_<1>>>::type For help, type "help". Metaprogram started (mdb) rbreak ^boost::mpl::plus Breakpoint "^boost::mpl::plus" will stop the execution on 25 locations (mdb) continue Breakpoint "^boost::mpl::plus" reached boost::mpl::plus<mpl_::integral_c<int, 1>, mpl_::int_<1>, mpl_::na, mpl_::na, mpl_::na> (Memoization) (mdb) bt #0 boost::mpl::plus<mpl_::integral_c<int, 1>, mpl_::int_<1>, mpl_::na, mpl_::na, mpl_::na> (Memoization) #1 boost::mpl::quote_impl<boost::mpl::plus<mpl_::integral_c<int, 1>, mpl_::int_<1>, mpl_::na, mpl_::na, mpl_::na>, true> (TemplateInstantiation) #2 boost::mpl::quote5<plus, mpl_::void_>::apply<mpl_::integral_c<int, 1>, mpl_::int_<1>, mpl_::na, mpl_::na, mpl_::na> (TemplateInstantiation) #3 boost::mpl::apply_wrap5<boost::mpl::quote5<plus, mpl_::void_>, mpl_::integral_c<int, 1>, mpl_::int_<1>, mpl_::na, mpl_::na, mpl_::na> (TemplateInstantiation) ... #19 transform<vector_c<int, 1, 2, 3, 4, 5>, plus<_1, int_<1>>>::type You can try Metashell from your browser: http://abel.web.elte.hu/shell Or you can install it on your computer: https://github.com/sabel83/metashell#version-200 Binary installers are available for a number of Linux distributions, Windows and Mac OS X. Feedback is welcome. Regards, Ábel

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Submit Changes for VxWorks
by Rogerio dos Santos 01 Dec '14

01 Dec '14

Dear Group, I am using boost on the current VxWorks platform and in order to get some of the libraries properly compiled I had to change some of the boost source code by considering certain includes when compiling for VxWorks. I would like to submit those changes however I am not aware of the procedure should I do to get those changes reviewed and properly available on the boost source control. Please can anyone let me know what should I do to submit those changes? Thanks in advance for your help. Roger.

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boost::async documentation
by Aaron Levy 29 Nov '14

29 Nov '14

I did not see any explicit documentation of the boost::async template although I see some mention of it since Boost 1.53. Is there some cohesive documentation which lists: 1. The macros needed to enable the functionality if any. 2. Details of behavior and limitations. 3. Differences in behavior wrt std::async. -- Aaron Levy aaron.levy(a)yandex.com

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boost.context cause strange crash on certan WIN32 API
by microcai 29 Nov '14

29 Nov '14

Hi, I was using Boost.Asio.Spawn happliy until I ported my project to windows. I got stange openssl crash. many debug days speeded and there was nothing wrong with openssl. Strange thing is, openssl didn't crash when used in normal code, unless I used them in asio stackful coroutine. Now I finnally find the root cause and make it 100% reproducible. here is the code that demostrade the crash: <code> boost::context::fcontext_t fcm,fc1; void f1(intptr_t) { HMODULE advapi = LoadLibrary(TEXT("advapi32")); // crash there FreeLibrary(advapi); boost::context::jump_fcontext(fc1, &fcm, 0); } std::thread([](){ boost::context::guarded_stack_allocator alloc; std::size_t size(8192); void* sp1(std::malloc(size)); fc1=boost::context::make_fcontext(sp1, size, f1); boost::context::jump_fcontext(&fcm, fc1, 0); }); </code> the context created in threads other that main thread, can't call certain APIs. If LoadLibrary get called by an context that created in thread, it will crash. 100% reproducible on WIN64 platform with MSVC2013. And nothing wrong on WIN32 !

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[Boost.Convert] Specify input using iterators
by Marius Dobrea 28 Nov '14

28 Nov '14

Hi Vladimir, While reading the Boost.Convert documentation last night there were some questions which came to my mind: Have you considered using iterators (or ranges) to specify input? Would that be in the scope of your library? Also I note that the strtol() function returns the position of the first invalid character (endptr below): long int strtol (const char* str, char** endptr, int base); Could convert() provide the position where the conversion stopped? This would allow single pass parsing of some input data. Would a Converter callable with the following signature be useful? template<typename TypeOut, typename InputIterator> class Result { public: enum Errc { numeric_overflow, empty_range, invalid_character, ...}; // std::expected like function signatures here private: TypeOut value; int errors; InputIterator pos; }; template<typename TypeOut, typename InputIterator> void operator()(InputIterator begin, InputIterator end, Result<TypeOut, InputIterator>& result) const; Please let me know your thoughts. Thanks, Marius Dobrea

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[optional] Safe optional
by Andrzej Krzemienski 28 Nov '14

28 Nov '14

Hi Everyone, I would like to run an idea through everyone in this list. There is a recurring complaint about Boost.Optional that it allows you to do "unsafe" things: 1. Inadvertent mixed comparisons between T and optional<T> 2. Unintended conversion from T to optional<T> 3. "Unchecked" access to the contained object, which causes an UB when performed on an uninitialized optional object. There are valid reasons why optional is defined the way it is defined. But at the same time the complaints above are also valid. This makes some people abandon Boost.Optional and use their own alternative. My idea is to provide another type wrapper, say safe_optional<T>, that would choose different tradeoffs: prefer "safety" to some flexibility and/or efficiency. It would probably be part of Boost.Optional library as the implementation can be reused - only the interface would be changed. One downside of this solution is that we would have two libraries for doing nearly the same thing, which could "scatter" the community. There is a value for standardizing certain things and making them universal. I would like to solicit your feedback. Regards, &rzej

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