January 2013 - Boost - lists.boost.org

[Release][Spirit] Asking for permission to merge a bugfix
by Hartmut Kaiser 20 Jan '13

20 Jan '13

Dear release managers, I would like to ask for permission to merge a changeset: Revision: 82521 Author: hkaiser Date: Thursday, January 17, 2013 7:33:58 AM Message: Fix #7900: karma indirect_iterator returns reference to temporary ---- Modified : /trunk/boost/spirit/home/karma/detail/indirect_iterator.hpp Modified : /trunk/libs/spirit/test/Jamfile Added : /trunk/libs/spirit/test/karma/regression_iterator.cpp I committed a couple of days ago in order to fix a newly discovered bug. Thanks! Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu

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[variant] Basic rvalue and C++11 features support
by Antony Polukhin 20 Jan '13

20 Jan '13

Hi, There is a patch in ticket #7620 that adds some rvalue assignment operators and rvalue constructors for Boost.Variant library. I saw no activity from authors of Boost.Variant Eric Friedman and Itay Maman for a long time, so if there will be no objections, I'll commit patch to trunk in the middle of November. Any suggestions and comments are welcomed. -- Best regards, Antony Polukhin

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permission to merge documentation
by Oliver Kowalke 20 Jan '13

20 Jan '13

I'd like to ask for permission to update the documentation of boost.coroutine. Oliver

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[1.53] program_options warning fix
by Vladimir Prus 20 Jan '13

20 Jan '13

May I merge the below fix to release branch? It was checked in July (so yeah, tests have cycles since then), but it seems I have failed to merge it until now. Index: boost/program_options/errors.hpp =================================================================== --- boost/program_options/errors.hpp (revision 79476) +++ boost/program_options/errors.hpp (revision 79477) @@ -250,7 +250,7 @@ } /** Does NOT set option name, because no option name makes sense */ - virtual void set_option_name(const std::string&option_name) {} + virtual void set_option_name(const std::string&) {} ~error_with_no_option_name() throw() {} }; -- Vladimir Prus CodeSourcery / Mentor Graphics http://www.mentor.com/embedded-software/

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[log] Documentation v2 mini review
by Klaim - Joël Lamotte 19 Jan '13

19 Jan '13

Hi, I took some time to read the new Boost.Log documentation, at leas the beginning and the parts that interest me the most. First, it is very complete and clear, so this is good. I didn't try the code yet but will report about it in coming weeks (I guess it's ok as no mini-review date have been set yet so I'll not be late). Here are some remarks, which are all minor improvements. Design overview: ================ 1. "The library was designed to be very modular and extensible." Maybe starting with "this library" or "Boost.Log" instead of "the library" would be clearer. Next: "The logging library " - remove this repetition. 2. "Both narrow and wide-character loggers provide similar capabilities, so through most of the documentation only the narrow-character interface will be described. The library provides configuration facilities to compile only the version of the library that's needed." So the recent changes you did concerning wide/narrow characters don't affect this part of the documentation? 3. The picture is good. A minor improvement: it would have been better if there was a clear sense that sources and sinks are unrelated. One possibility would be to have crossing arrows in the logging core to express the possibility of having custom source routed to alarms for example. It's a minor improvement anyway, I just fear that visual alignement suggest a direct relationship between sinks and sources. A simpler possibility would be to make the sinks smaller and unaligned from the sources, like this: +-----------+ embedded loggers => | | | | => logs | | | Logging | => (something else) global loggers => | | | core | => alarms | | | | => statistics custom log sources => | | +-----------+ Formatting might be wrong in your email interface so here is the same with right formatting: http://pastebin.com/itPRd66k Which I think would make clear that both concept are not directly linked. 4. " - from parts of your application at the left to the final storage, if any, at the right" It seems that there is a missing coma? Maybe: " - from parts of your application, at the left, to the final storage, (if any) at the right" 5. In this document (and other pages), you are often listing different kind of things. I think it might be even clearer or fast to read if you used bullet points when you are listing possible variants. For example, attribute sets kinds could have each their bullet. To be clear: the current doc is fine as it is now, it's only a potential improvement remark. Trivial logging with filters ============================ 6. "The filter is built as a lambda expression." Maybe a remark related to C++11 lambda might be important here (or before)? To explain the difference with what you're doing in the example. Because it's not obvious here that you're utilizing another library to accept another style of lambda. In general, a note about supporting or not C++11 might be helpful as this library will be new to boost distribution users. Hope it helps. Joel Lamotte

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[Serialization] Bizarre bug - reviewed
by Tobias Loew 17 Jan '13

17 Jan '13

I just came across the following bug http://boost.2283326.n4.nabble.com/Serialization-Bizarre-bug-td2612558.html and noticed that the bizarre behaviour is still reproducible (I used boost-version 1.52). I could figure out that in the buggy build there is an additional static initialization of the singlenton<T>::instance in boost\serialization\singleton.hpp in line 149 at startup > serial_bug.exe!`dynamic initializer for 'boost::serialization::singleton<boost::archive::detail::pointer_oserializer<boost::archive::text_oarchive,std::vector<char,std::allocator<char> > > >::instance''() Zeile 149 C++ which leads to a call of set_bpis in iserializer.hpp line 347. Thus, std::vector<char> will be saved (but NOT loaded) through a pointer. For apps that store and load the same types the problem usually does not arise, but for server/clients this may not be the case (e.g. apps using the RCF-library) Tobias -- View this message in context: http://boost.2283326.n4.nabble.com/Serialization-Bizarre-bug-reviewed-tp464… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Changes to VS 2012 config
by Marshall Clow 17 Jan '13

17 Jan '13

Just so people know - I'm updating the Visual Studio configuration to more accurately reflect the capabilities of VS 2012. The first step was in http://svn.boost.org/trac/boost/changeset/81613 ; the next step will be to update the compiler features. If you see any problems, please let me know. -- Marshall

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Interest in breakable labeled scope emulation?
by TONGARI 16 Jan '13

16 Jan '13

Hi all, One of the few things I appreciate in Java is the labeled-break feature. I think C++ would provide it as well in future standard but it seems that there's no even such a proposal. In lack of the language feature, a simple emulation can be used: --------------------------------------------------- #define BOOST_SCOPE(name) \ if (const bool LABELED_SCOPE_##name = false){break(name); name:;} else #define break(name) \ (void)LABELED_SCOPE_##name; goto name; --------------------------------------------------- Now we can write: BOOST_SCOPE(a) { break(a); cout << "123\n"; } The real world usage would reside in nested loop&switch where labeled-break really shines. Thoughts? Sorry if this idea is too simple and somewhat rejected before...

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[thread] Can Boost.Thread use Boost.Atomic without falling on a compatibility issue?
by Vicente J. Botet Escriba 14 Jan '13

14 Jan '13

Hi, in order to fix this issue, https://svn.boost.org/trac/boost/ticket/5752 : "boost::call_once() is unreliable on some platforms", I would like to use Boost.Atomic as suggested on the ticket. As Boost.Atomic is not a header-only library the user would need to link with boost_atomic. Is this an acceptable change? I'm requesting this as recently there were some people reactive to some changes in Boost.Thread. Would this be considered an compatibility issue? If yes should the fix for the call_once issue be included if the user request it using conditional compilation or even go on a separated version of Boost.Thread? Thanks, Vicente

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[serialization] round-trip serialization of float
by Adam Lerer 14 Jan '13

14 Jan '13

The boost serialization of float doesn't appear to use enough digits to guarantee that deserialization of a serialized value will produce the same value. The relevant code is in boost/archive/basic_text_oprimitive.hpp: void save(const float t) { os << std::setprecision(std::numeric_limits<float>::digits10 + 2); ... } std::numeric_limits<float>::digits10+2=8, but float actually requires numeric_limits<float>::max_digits10=9 decimal digits to guarantee unique representation. The code below (with boost/1.52) demonstrates the problem: #include <sstream> #include "boost/archive/text_iarchive.hpp" #include "boost/archive/text_oarchive.hpp" #include <iostream> int main(int argc, char **argv){ float oldf = -1.20786635e-05; std::ostringstream os; boost::archive::text_oarchive oa(os); oa & BOOST_SERIALIZATION_NVP(oldf); float newf; std::istringstream is(os.str()); boost::archive::text_iarchive ia(is); ia & BOOST_SERIALIZATION_NVP(newf); printf("before serialization: %.12g\nafter serialization: %.12g\n", oldf, newf); } // Output: // before serialization: -1.20786635307e-05 // after serialization: -1.20786644402e-05 Note: There's some discussion of this topic in a slightly different context here: http://boost.2283326.n4.nabble.com/serialization-Serialisation-deserialisat…

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