July 2011 - Boost - lists.boost.org

Using clang built with MSYS/Mingw on Windows
by Edward Diener 06 Jul '11

06 Jul '11

I have been able to build clang using MSYS using the instructions on the clang web site. Everything appears to have built correctly except for a problem building the llvm sample program which I reported, and nobody has responded to. So I will ignore the problem as I see I have a clang.exe and a clang++.exe in the build/llvm/Debug+Asserts/bin directory. I have a number of questions: 1) Do I need to re-run 'configure' followed by 'make' each time I get the latest llvm and clang from SVN, or is running 'make' good enough. 2) How does clang find its headers and libraries ? In the clang User Manual under "Operating System Features and Limitations" for Mingw32 it says: "MinGW32 Clang works on some mingw32 distributions. Clang assumes directories as below; C:/mingw/include C:/mingw/lib C:/mingw/lib/gcc/mingw32/4.[3-5].0/include/c++" This is a little confusing to me. When running clang, built through MSYS, does clang understands Windows paths or does it need to be run from within MSYS and therefore understand only Linux-like paths ? The note suggests the former. 3) Can clang handle the Windows header files used by gcc in its include directory as specified above ? 4) What is the difference between clang and clang++.exe ? I do not mean to be critical because I know that many developers are working to make clang better, but the online Users Manual is pretty sparse in information, so I am hoping someone can help me here or point me to better explanations. I want to use clang to test out Boost libraries on which I am working. I heavily prefer staying on Windows so I am hoping I can use clang there. Thanks !

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On #5644 (tellg returns different results for gnu libstd++ and others standard libraries for codecvt_null)
by Michael Kochetkov 05 Jul '11

05 Jul '11

Hello, please can anyone comment on https://svn.boost.org/trac/boost/ticket/5644 issue? I am really stuck with the problem and need just a resolution if it is a defect or not. And if it is then I would appreciate an approximate estimate when it is to be fixed. Thank you in advance, -- Michael Kochetkov

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Phoenix V3 and Logging library help.
by Fernando Pelliccioni 05 Jul '11

05 Jul '11

Hi Thomas, all, I am researching about logging libraries. I had to discard Boost.Log ( from Andrey) because this library does not support GCC 3.4. I've seen other libraries, but none convinced me. I'm thinking of writing a simple logging library, and to avoid the use of macros, I decided to do something like this: namespace prototype1 { namespace levels { boost::phoenix::expression::argument<1>::type const trace = {{{}}}; boost::phoenix::expression::argument<1>::type const debug = {{{}}}; boost::phoenix::expression::argument<1>::type const info = {{{}}}; boost::phoenix::expression::argument<1>::type const warn = {{{}}}; boost::phoenix::expression::argument<1>::type const error = {{{}}}; boost::phoenix::expression::argument<1>::type const fatal = {{{}}}; } //namespace levels struct dynamic_logger { template <typename Pred> void log( Pred const & pred ) const { streams_type::const_iterator it = streams_.begin(); streams_type::const_iterator end = streams_.end(); for ( ; it != end; ++it ) { pred( **it ); } } void add_target ( std::ostream & ostr ) { streams_.push_back( &ostr ); } typedef std::vector< std::ostream* > streams_type; //to improve streams_type streams_; }; template <typename Logger, typename Pred> void log( Logger & logger, Pred const & pred ) { return logger.log(pred); } } //namespace prototype1 int main(/*int argc, char* argv[]*/) { { using namespace prototype1; using namespace prototype1::levels; std::ofstream outfile ("test.log"); dynamic_logger dl; dl.add_target( std::cout ); dl.add_target( outfile ); dl.log ( info << "hello" << " world!" << std::endl ); dl.log ( warn << "hello" << " world!" << std::endl ); dl.log ( error << "hello" << " world!" << std::endl ); log( dl, info "hello" << " world!" << std::endl ); //free function } return 0; } This code is a simple prototype, This code is a prototype should be improved. The questions are: 1. Does PhoenixV3 (and Proto) supports GCC 3? 2. How to make the above code write the following ... ? INFO - hello world! WARN - hello world! ERROR - hello world! INFO - hello world! Is it possible? The key is to identify the different Levels. (see namespace prototype1::levels) Please, suggestions and criticisms are welcome. Note: I do not intend to compete with Boost.Log. Thanks and regards, Fernando Pelliccioni.

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[introspection] if a function is not public
by Lorenzo Caminiti 05 Jul '11

05 Jul '11

Hello all, Is there any way (SFINAE, etc) to check at run-time or at compile-time if a member function is not public? class x { public: void f ( ) {}; protected: void g ( ) {}; private: void h ( ) {}; bool is_public(...) { ... } // some implementation void check ( ) { std::cout << is_public(x::f) << std::endl; // 1 std::cout << is_public(x::g) << std::endl; // 0 std::cout << is_public(x::h) << std::endl; // 0 } }; Thanks a lot! --Lorenzo

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Namespace policy: putting names in boost::detail
by Mathias Gaunard 05 Jul '11

05 Jul '11

A GSoC student and I are currently converting a library to use the namespace boost::simd. Some of the implementation details of the library are not simd-specific, and we would like to use them in some other libraries that extend boost::simd. Would it be ok to put them in the boost::detail namespace, or is that considered as bad as putting stuff in the boost namespace? We need to inject overloads and specializations into a unique namespace for boost.simd and NT2, so we could need two names, like boost::detail::dispatch and boost::detail::specialize.

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[review][assign] Assign v2 review result
by John Bytheway 04 Jul '11

04 Jul '11

There was only one explicit review of the Assign v2 library, from Lars Viklund, which voted against inclusion. Other discussion about the library did not have an overwhelmingly positive tone. Therefore, the library is NOT accepted for Boost at this time. Some of the issues raised in discussion were: - The tutorial examples are terse, and move too quickly into the more advanced features of the library. - Code written with the library is too obtuse to those not familiar with it. - The naming conventions are unintuitive, in particular several people did not understand 'csv' without consulting the docs. - Does the impending arrival of initializer lists in C++0x render some or all of the functionality obsolete? - The documentation's performance metrics do not cover compile time. - There are portability issues to some less mainstream compilers. In conclusion, I think the review highlighted a few serious and interrelated issues with the library as it stands: 1. The scope of the library is not clear. If it is simply intended to save typing, and act as a filler for such things as initializer lists, then why does it need such complexity? On the other hand, if it is intended for more than this, then what is the motivation? The docs do not make this clear. 2. The tutorial moves too quickly, is unclear to newcomers, and lacks clear motivation for its examples. It would be better to spend more time explaining each example, perhaps with English or with equivalent code not using Assign v2. The existing Boost.Assign docs were compared favourably with the Assign v2 docs by more than one reviewer, and might serve as a model for improvement. 3. Code written with the library is obtuse and a developer unfamiliar with its ideas would be unable to decipher it without documentation. Furthermore, in some cases even with the existing documentation the intent of the code was unclear. For a task as conceptually simple as the library attempts to tackle it should be possible to make the code using it much more clear. There may be more problems with the library, but the presence of these issues prevented most reviewers investigating any more deeply. If Erwann wishes to continue his development of the library, and perhaps have it, or some subset of it, included in Boost in the future, then I recommend that he first establish a clearly motivated scope, and then strive for a syntax clear even to the uninitiated. I would like to thank Erwann again for all his hard work, and everyone who participated in the discussion during the review. John Bytheway Review Manager

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Re: [boost] [math] Empirical distribution function
by Denis Arnaud 04 Jul '11

04 Jul '11

2011/6/15 <boost-request(a)lists.boost.org> > Date: Wed, 15 Jun 2011 09:35:49 -0400 > From: er <er.ci.2020(a)gmail.com> > > > distributions< > http://www.boost.org/doc/libs/1_46_1/libs/math/doc/sf_and_dist/html/math_to… > >. > > But an accumulator is just fine for now. By the way, does it mean that if > we > > have a set of 1 million of distinct real numbers, the corresponding > > accumulator will store a pretty big number of counters? > > > > Only if the million are distinct values. Otherwise it keeps each > distinct value + a count. > Ok, that's how I understood it, then (even though I'm not sure that that's the way accumulators are supposed to be used). > I'm glad you like the idea of a wrapper on top of an accu, but I only > plan to do the accu. Please give me a bit of time to do a bit of > maintenance work, though. I'll keep you updated. > It sounds perfect: thanks! D

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[log] init_from_settings - problem with applying format and filter
by Petrovskiy Yuriy 04 Jul '11

04 Jul '11

I am trying to use boost::log for tracking application activity. I need message with severity level output to console and more detailed output to file. I have the following code (most of it is copied from boost::log documentation): /* boostLogTest.cpp */ #include <boost/log/sources/severity_logger.hpp> #include <boost/log/sources/record_ostream.hpp> #include <boost/log/utility/init/from_settings.hpp> using namespace boost::log; enum logMessageSeverityLevels { trace = 0 , debug = 1, info = 2, warning = 3, error = 4, fatal = 5 }; #define LOG(x) BOOST_LOG_SEV(logger, x ) typedef boost::log::sources::severity_logger< logMessageSeverityLevels > loggerType; loggerType logger(keywords::severity = error); int main() { boost::log::settings setts; //setts["Core"]["Filter"] = "%Severity% >= 0"; //if set - no output anywhere setts["Core"]["DisableLogging"] = false; setts["Sink:Console"]["Destination"] = "Console"; setts["Sink:Console"]["Filter"] = "%Severity% >= 3"; // no output to console in result setts["Sink:Console"]["Format"] = "[%Severity%] %_%"; setts["Sink:Console"]["AutoFlush"] = true; setts["Sink:File"]["Destination"] = "TextFile"; setts["Sink:File"]["FileName"] = "test_%3N.log"; setts["Sink:File"]["Format"] = "[%TimeStamp%] <%Severity%> %_%"; setts["Sink:File"]["AutoFlush"] = true; boost::log::init_from_settings(setts); LOG(info) << "!!!Hello World!!!"; LOG(warning) << "NO TimeStamp and Severity"; LOG(error) << "NO output if Filter is set "; return 0; } result: no output to console file (test_000.log) is being rewritten on each run: [] ** !!!Hello World!!! [] ** NO date [] ** NO severity [] ** NO output if Filter is set if I add #include <boost/log/trivial.hpp> and replace LOG definition with #define LOG(x) BOOST_LOG_TRIVIAL( x ) I get also no console output but TWO! logs: (boostLogTest.log) 1 [2011-Jul-04 12:14:06.331749] [0x73d190] [info] !!!Hello World!!! 2 [2011-Jul-04 12:14:06.338750] [0x73d190] [warning] NO TimeStamp and Severity 3 [2011-Jul-04 12:14:06.339750] [0x73d190] [error] NO output if Filter is set .... ( test_000.log ) [2011-Jul-04 12:14:06.331749] ** !!!Hello World!!! [2011-Jul-04 12:14:06.338750] ** NO TimeStamp and Severity [2011-Jul-04 12:14:06.339750] ** NO output if Filter is set Built with: g++ -Ipath\to\boost -O0 -g3 -Wall -c -fmessage-length=0 -osrc\boostLogTest.o ..\src\boostLogTest.cpp g++ -Lpath\to\boost\libs -oboostLogTest.exe src\boostLogTest.o -lboost_log-mgw45-mt-d-1_46_1 -lboost_log_setup-mgw45-mt-d-1_46_1 Environment: Windows 7 x64 / MinGW (gcc 4.5) / Eclipse Boost version 1.46.1 Boost log from https://boost-log.svn.sourceforge.net/svnroot/boost-log/trunk/boost-logRevi… 603 Boost built with the same toolset. The questions are: - How to configure severity_logger using init_from_settings() to get the custom severity levels in the log? - Why "Format" variables do not work? (and why %TimeStamp% starts to work if using BOOST_LOG_TRIVIAL for output)? - What should be done to make logger append to log (not overwrite)? - Is it possible to log file and line using format variables (only to file)? I had explored boost::log documentation but had not found answers for these questions. Thank you in advance. Yuriy Petrovskiy

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Is boost log dead?
by Espen Harlinn 04 Jul '11

04 Jul '11

Has the boost log library died? Regards Espen Harlinn <mailto:espen@harlinn.no> mailto:espen@harlinn.no

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[1.47] Merge request for Boost.Build testsuite
by Vladimir Prus 03 Jul '11

03 Jul '11

May I please merge this change: https://svn.boost.org/trac/boost/changeset/72883 which unbreaks Boost.Build regression tests. Since Boost.Build tests are not run unless they are explicitly run, this change has no potential to break the release. However, it certainly will make Boost.Build tests look much better than they are now. OK? -- Vladimir Prus CodeSourcery / Mentor Graphics +7 (812) 677-68-40

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