March 2015 - Boost-users - lists.preview.boost.org

Re: [Boost-users] [scope_exit] 1.57 MSVC C4003 warning
by Cheng Mo 16 Mar '15

16 Mar '15

Hi Filip: It is happened on VS 2010 as well. Hi Edward: Excuse me about this question postponed. I have just had this problem and have found this thread. Could you tell me what mean by "BOOST PP level" does ? Thanks. Sincerely Mo.Cheng

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Boost 1_58_0_rc1 is available for testing
by Marshall Clow 16 Mar '15

16 Mar '15

Release candidate files for 1.58.0 beta 1 are available at http://boost.cowic.de/rc/ 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. This helps ensure the candidates build OK before we push them out to SourceForge. IMPORTANT NOTE: There is a bug with the build scripts; you have to specify the address-mode and architecture to b2. I used: ./b2 address-model=64 architecture=x86 to test this. The files (and associated md5s) are: MD5 (boost_1_58_0_b1_rc1.7z) = 302c7dfc917227843d24beed33ccc99c MD5 (boost_1_58_0_b1_rc1.tar.bz2) = d7d030e85bf5534a328c108c62a7fb0e MD5 (boost_1_58_0_b1_rc1.tar.gz) = ec90cd23bdc99c5eaf88245ea94a28e0 MD5 (boost_1_58_0_b1_rc1.zip) = dc8379fb95c84fe2fca53a4b2c96da23 Thanks! -- The release managers

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[Asio] Need help making a custom service
by Kyle Edwards 16 Mar '15

16 Mar '15

Hello everyone, First off, I would like to say that I have been using Boost for the past few years, and have found it very useful. Thanks for all your hard work! Second, I have a question about making a custom service. I would like to make a service that triggers a callback when a GPIO pin changes state and triggers an interrupt (I'm using a Raspberry Pi.) I have (or can obtain) a file descriptor that can be poll()'d, select()'d, or epoll'd and which omits high-priority events (POLLPRI, EPOLLPRI, etc.). This entire use case is pretty Linux-specific, so it doesn't have to be very portable. What I would like to be able to do is something like this: // CODE STARTS HERE #include <iostream> #include <boost/asio.hpp> class gpio_interrupt { public: gpio_interrupt(boost::asio::io_service &io_service, unsigned int number) { // Asio magic goes here } template <typename Callback> void async_wait(Callback c) { // Asio magic goes here } }; static void my_callback(const boost::system::error_code &ec) { if (ec) return; std::cout << "Pin changed state" << std::endl; } int main(int argc, char **argv) { boost::asio::io_service io_service; gpio_interrupt interrupt(io_service, 21); interrupt.async_wait(my_callback); io_service.run(); return 0; } // CODE ENDS HERE I've looked a little bit at the Boost.Asio code (in particular the socket code) to get an idea of how I would do this, but there are so many different classes and inner classes that I'm not sure where to get started. Can someone help me? Thanks in advance! -- Kyle Edwards Software Developer 20 Corporate Circle | Albany, NY 12203 office 888-4BULLEX | 518.689.2023 | fax 518.689.2034 | web: www.bullex.com

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[context] Crash in case of exception from a context
by Tamas.Ruszkai＠leica-geosystems.com 16 Mar '15

16 Mar '15

I use boost::context to implement cooperative multitasking. At the moment I use boost 1.57 on Windows 7 with VisualStudio 2013. Everything works fine until I throw an exception from a context created by "boost::context::make_fcontext(.......)". I have seen someone had the same problem and it was caused by the Windows OS, that checks the exception hierarchy in the stack and if it finds that the starting point is not the one that should come from the OS then it terminates the process. It suspects some malitious code that corrupted the stack. http://www.blinnov.com/en/2013/04/11/english-boostcontext-and-seh/ This guy metioned in his blogpost, that this problem was solved in boost 1.53 ("Boost 1.53 has updated and fixed version of boost::context library that addresses exactly this problem. "), but somehow I still have the same thing in 1.57. Is there some special preprocessor flag (#define) that I have to activate to get this fix? Thanks! Tamas

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Boost forces Cygwin build to be 32-bit, even when it shouldn't
by Chris Taylor 15 Mar '15

15 Mar '15

I'm having trouble building boost under Cygwin. I've installed the 64 bit version of Cygwin and all programs are compiled as 64 bit. Yet, for some reason, the header ./boost/python/detail/wrap_python.hpp defines SIZEOF_LONG to be 4 when __CYGWIN__ is defined, which is only valid for a 32-bit system. This signals an error check in a python header, and the build fails. Why does this #define exist? Can we get rid of it? More info here: http://stackoverflow.com/questions/29004590/compiling-boost-on-cygwin-heade…

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[regex] stuck with expression syntax / exception
by Thomas 15 Mar '15

15 Mar '15

Hi, I am pretty much a complete novice to the boost::regex library, and stuck with the following snippet: std::string String = " (of 1000 elements; 67.10%)"; try { std::cout << boost::regex_match(String, boost::regex("^ (of \\d+ elements; .+%)$")) << std::endl; std::cout << boost::regex_match(String, boost::regex(" (of \\d+ elements;.+")) << std::endl; } catch(boost::regex_error const &) { std::cout << "caught boost::regex_error!"; } Two questions: First, why does the first not match? Second, why does the second throw? The idea of the regex is that the first number is an integer, and for the percentage number the formatting is unspecified but must terminate with '%'; otherwise all characters must match exactly. thanks, Thomas

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[Range] concatenate 2 vectors
by Christophe B. 14 Mar '15

14 Mar '15

Hi all, I want to construct a static const vector being the result of concatenation of two other vectors. I was thinking to use boost::push_back, but it takes a container as a lvalue reference as a 1st argument. I could develop the following piece of code template <typename Container, typename Range> Container concat(Container const &c, Range cont& r) { Container result = c; return boost::push_back(result, r); } static const std::vector<std::string> v = concat(v1, v2); But I wanted to avoid to reinvent the wheel. Currently, I am living with this kind of writing: static const auto v = [&]{ std::vector<std::string> result = v1; return boost::push_back(result, v2); }(); Does boost libraries offer a better alternative to this construct ? Christophe

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Need site-config.jam msvc example for cxxflags
by David Highley 13 Mar '15

13 Mar '15

> We are beating our head on the wall trying to get site-config.jam to add > an include path for the Windows SKD includes. We have tried many flavors > of this: > > using msvc : 12.0 : : <cxxflags>"-IC:\\Program Files (x86)\\Microsoft > SDLs\\Windows\\v7.1A\\Include" ; We found the magic and the file now looks like this. using msvc : 12.0 : : <compileflags>"-I\"C:\\Program Files (x86)\\Microsoft SDKs\\Windows\\v7.1A\\Include\"" ; > > > We need it to only be used with the 12.0 or Studio 2013 version of > Studio. >

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Need site-config.jam msvc example for cxxflags
by David Highley 13 Mar '15

13 Mar '15

We are beating our head on the wall trying to get site-config.jam to add an include path for the Windows SKD includes. We have tried many flavors of this: using msvc : 12.0 : : <cxxflags>"-IC:\\Program Files (x86)\\Microsoft SDLs\\Windows\\v7.1A\\Include" ; We need it to only be used with the 12.0 or Studio 2013 version of Studio.

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Re: [Boost-users] Boost 1_58_0_rc1 is available for testing - coroutine2 missing
by Oliver Kowalke 12 Mar '15

12 Mar '15

boost.coroutine2 is missing in the archive

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