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[Optional] Lazy initialized optional
by Michael Powell 14 Nov '18

14 Nov '18

Hello, I am looking into deriving from boost::optional and adding lazy initialization capability. I can arrange a constructor, or whatever, to inject an appropriate factory method, functional callback, etc, that's no problem. >From the boost::optional perspective, I'd like to override a key method (or methods, hopefully not too many) in order to inject that factory provided value. I'm thinking optional::get? Unless there's a better override for that? Cheers, Michael Powell

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[release] Boost 1.69.0 Beta 1 Release Candidate 1
by Marshall Clow 14 Nov '18

14 Nov '18

The release candidates for the first 1.69.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta.1.rc1/source/> The release notes are not yet available. The updated documentation is not yet available. [ They will be available in a day or two. ] The SHA256 checksums are as follows: db6b346389714647490d6503db881e4178dd8cd498f850999bebf72cacd4c4ed boost_1_69_0_b1_rc1.7z d128c82351becbd37a02b9b4818994d3f66ff8bdbc0a18838206f4c070db97af boost_1_69_0_b1_rc1.tar.bz2 4df6262db53cfd0d0f934cb126f7e48e94872fe4441cbac6bf72a43bfb136a45 boost_1_69_0_b1_rc1.tar.gz e2908e33cc15f92cda06ddde6a3da43b18967a83105355571fc3cf6e75820c7f boost_1_69_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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Trouble building boost
by Vipin Verma 13 Nov '18

13 Nov '18

Hello I have tried building boost on my Windows as well as Ubuntu system, but I am not able to make it work. Could you please help me? Here is a post with details about Windows - https://stackoverflow.com/questions/53273860/opennero-windows-could-not-fin… Here is a post about Ubuntu - https://stackoverflow.com/questions/53151130/opennero-ubuntu-process-finish… -- Regards Vipin Verma <https://www.linkedin.com/in/vipin8169> BlueSapling Technologies Pvt Ltd. <https://bluesapling.com/> +1-480-410-1673

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[Variant] Minimum implementation to be variant friendly
by Michael Powell 13 Nov '18

13 Nov '18

Hello, What's the minimum implementation a struct needs to fulfill in order to be boost::variant friendly? Things like, does it need to support perfect forwarding? An assignment operator? And so on. Thanks! Michael Powell

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[Spirit] Qi int_parser rejecting a negative signed std::intmax_t
by Michael Powell 12 Nov '18

12 Nov '18

Hello, qi::int_parser works fine for a positive signed hex radix integer, but is failing for a negative signed hex radix integer. My integer type is std::intmax_t, which on this platform I think is long long. Is there an integer width constraint? And/or a signage problem? Do I need to enable BOOST_HAS_LONG_LONG? Or is that enabled by default? Cheers, thanks! Michael Powell

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Boost 1.68.0 contains only python 3.7 library, no python 2.7 library?
by Heng Zhou 10 Nov '18

10 Nov '18

Hi, I installed Boost 1.68.0 recently from Windows x64 pre-compiled binary "boost_1_68_0-msvc-14.0-64.exe" downloaded from https://urldefense.proofpoint.com/v2/url?u=https-3A__sourceforge.net_projec…. Then, I noticed that this version of Boost contains only python 3.7 library because the filenames under C:\local\boost_1_68_0\lib64-msvc-14.0 are only boost_python37-vc140-mt-.... This caused errors from building a third-party library which tries to link Boost python 2.7 library (i.e., tries to find file boost_python27-vc140-mt-...) . So what is matter? Does Boost decide to stop supporting python 2.7 since version 1.68.0, or is Boost python 2.7 library located somewhere else using some hard-to-recognize filename? I'm using Windows 10, VS2015 and have only python 2.7 installed. Thank you for your help with this issue.

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[Format] Possible to format numeric values using radix?
by Michael Powell 09 Nov '18

09 Nov '18

Hello, For instance, given a numerical value, I'd like to specify the Radix, whether to format octal or hex. Thanks in advance! Best regards, Michael Powell

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[DLL] BOOST_DLL_ALIAS not working on MinGW-w64
by David Demelier 09 Nov '18

09 Nov '18

Hello, I'm using boost 1.68 on MinGW-w64 (Windows 10). I'm trying a simple plugin that works fine under Linux and FreeBSD However, on Windows boost::dll::import_alias triggers an exception: terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::system::system_error> >' what(): boost::dll::shared_library::get() failed: The specified procedure could not be found This is the plugin (plugin.cpp) #include <iostream> #include <boost/dll.hpp> namespace custom { void my_function() { puts("CALLED"); } } // !custom BOOST_DLL_ALIAS(custom::my_function, my_function) I compile using: g++ -std=c++17 -shared -o plugin.dll plugin.cpp -lboost_system-mt And the simple main.cpp file: #include <boost/dll.hpp> int main() { using my_function = void (); auto f = boost::dll::import_alias<my_function>("./plugin.dll", "my_function"); } What's strange, nm does not report any kind of unmangled symbols related to "my_function": $ nm plugin.dll | grep my_function 0000000067e81422 t _GLOBAL__sub_I__ZN6custom11my_functionEv 0000000067e813b0 T _ZN6custom11my_functionEv It should contains something starting with boostdll_ isn't it? What's happening there? Do I miss something? -- David

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[Spirit] Qi lexeme only taking the first word
by Michael Powell 08 Nov '18

08 Nov '18

Hello, I've got a couple of rules that are perplexing to me. First, rule<It, std::string(), St> id %= lexeme[qi::alpha >> *char_("A-Za-z0-9_")]; In and of itself, id is working fine. Then I've got a "full id": rule<It, full_id_t(), St> full_id %= id >> *(char_('.') >> id); Where: struct full_id_t { std::string val; }; full_id_t::val is quite intentional for reasons elsewhere in the grammar. The perplexity comes in, it seems lexeme is only shaving off the first word as the val. For instance, parsing "two.oranges.red.test", I receive back "two" in the AST. Perhaps I should defer specifying the lexeme part of id until later? Thoughts? Suggestions? Thank you! Best regards, Michael Powell

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Build/use Boost without ICU
by braden 08 Nov '18

08 Nov '18

How does one build (and use) Boost without ICU when ICU is installed (i.e., visible to b2)? I am am bootstrapping with: ...which shows: Seems reasonable so far. Building happens with: ...which shows: In spite of passing "--disable-icu -sboost.locale.icu=off" to b2, I still see Boost.Locale getting built with -DBOOST_LOCALE_WITH_ICU=1; e.g.: What's the correct way to do this? ----- Braden McDaniel braden(a)endoframe.com -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

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