September 2014 - Boost-users - lists.preview.boost.org

BOOST_PP_ERROR(0x0003, BOOST_PP_REPEAT_OVERFLOW) with multiply nested BOOST_PP_REPEATS
by Colin Fowler 26 Sep '14

26 Sep '14

I'm having a problem with multiple nested repeats. I need to generate int x_0_0_0_0 to int x_a_b_c_d. Attempting to do so results in a BOOST_PP_ERROR. For readability, a few shorter defines #define TUPLE_ELEM BOOST_PP_TUPLE_ELEM #define REPEAT BOOST_PP_REPEAT and I also neglect the necessary BOOST_PP_CAT statements in DECL4D in this example #define DECL4D(z, n, text) TUPLE_ELEM(3, text) TUPLE_ELEM(0, text) TUPLE_ELEM(1, text) TUPLE_ELEM(2, text) n; #define DECL4C(z, n, text) REPEAT(TUPLE_ELEM(0, text), DECL4D, (TUPLE_ELEM(1, text), TUPLE_ELEM(2, text), n, TUPLE_ELEM(3, text))) #define DECL4B(z, n, text) REPEAT(TUPLE_ELEM(0, text), DECL4C, (TUPLE_ELEM(1, text), TUPLE_ELEM(2, text), n, TUPLE_ELEM(3, text))) #define DECL4A(z, n, text) REPEAT(TUPLE_ELEM(0, text), DECL4B, (TUPLE_ELEM(1, text), TUPLE_ELEM(2, text), n, TUPLE_ELEM(3, text))) #define decl4(a, b, c, d, text) REPEAT(a, DECL4A, (b, c, d, text)) decl4(1, 1, 1, 1, int x_) Am I hitting a nesting depth limit or something else? Is there a way around this? Ideally I want to write a decl5 macro and have successfully written a decl1, decl2 and decl3 so far Regards, Colin

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[fusion] problem converting the result of a transform of a set into a map
by Christian Kerl 26 Sep '14

26 Sep '14

Hello everybody, I've a problem with the boost fusion library. I try to convert a fusion set into a map using the transform algorithm. Here is a example: typedef typename boost::fusion::result_of::as_map< typename boost::fusion::result_of::transform<BoundMembers, map_name_to_member>::type >::type Content; where BoundMembers is a boost::fusion::set and map_name_to_member is defined as: struct map_name_to_member { template <typename T> struct result; template <class F, typename T> struct result<F(T)> { typedef boost::fusion::pair<typename T::Name, typename T::Member> type; }; }; With boost 1.56 and gcc 4.8.1 I get the following compilation error: include/boost/fusion/iterator/key_of.hpp:36:16: error: invalid use of incomplete type ‘struct boost::fusion::extension::key_of_impl<boost::fusion::transform_view_iterator_tag>’ struct key_of ^ include/boost/fusion/iterator/key_of.hpp:21:16: error: declaration of ‘struct boost::fusion::extension::key_of_impl<boost::fusion::transform_view_iterator_tag>’ struct key_of_impl; However, this code used to work with Boost 1.48. I found a workaround to fix this, by converting the result of transform to a fusion list before coverting it to a map, i.e.: typedef typename boost::fusion::result_of::as_map< typename boost::fusion::result_of::as_list< typename boost::fusion::result_of::transform<BoundMembers, internal::map_name_to_member>::type >::type >::type Content; Am I doing something wrong or is this intended behavior? Thanks for your support. Best regards, Christian Kerl

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Re: [Boost-users] boost logger architecture
by Savva Kuznetsov 26 Sep '14

26 Sep '14

Hi, Tony. It would be great to have an opportunity to know which file is currently being used for logging and set another, for example. Also, we want to control logs rotation and set conditions in which current file must be stored into collection, and create new file with the same name. It would be much easier task and I guess it would be the true boost-style, if boost\log\sinks\text_file_backend.cpp was not hiding a lot of definitions and class interfaces. S.K.

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boost logger architecture.
by Savva Kuznetsov 25 Sep '14

25 Sep '14

Hello, guys. This post is almost the entire duplicate of my Ticket #10524. We're using boost logger in our application and it's really great boost library part. But, we need to change some of it's functionality. Actually, we need to add some lines of code in a method of collector class (for example, file_collector from boost\log\sinks\text_file_backend.cpp) I guess the right way to do this is inheritance from file_collector class and redefinition of it's members functions. But, since it's entire declaration and definition are in text_file_backend.cpp file in an anonymous namespace, it's impossible. Also, it would be cool to use some functions that this class uses (these functions are in text_file_backend.cpp file too for some unknown reason). The only solution I see is to copy-and-paste the entire file_collector class code from boost\log\sinks\text_file_backend.cpp and rewrite some of it's methods content, but, it's obviously wrong and not beautiful way (not boost-way). I guess boost must provide an extensible way to do things. Is there any reason that the entire class is in text_file_backend.cpp file or maybe I am missing something? My ticket have been closed by the author of logger with the comment: "file_collector in text_file_backend.cpp is not designed to be extensible because the interface for the extension is not clear. This made the implementation simpler." It's kinda strange reason, is it?

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List of supported locales and time-zones
by niXman 25 Sep '14

25 Sep '14

Hi, Can somebody tell me please, how can I get a list of supported locale names and time-zones using boost.locale? Thanks. -- Regards, niXman ___________________________________________________ Dual-target(32 & 64-bit) MinGW-W64 compilers for 32 and 64-bit Windows: http://sourceforge.net/projects/mingw-w64/ ___________________________________________________ Another online IDE: http://liveworkspace.org/

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boost.python built with VC2010
by Mohammed El-Afifi 25 Sep '14

25 Sep '14

Hello, I have successfully built boost.python with visual c++ 2010(dynamic library, 64-bit). I have python 2.7.8 64-bit installed on windows 7 64-bit. I've read here https://docs.python.org/2/distutils/apiref.html#module-distutils.msvccompil… that python extensions should be built with the same compiler that was used to build python itself. My question is, since python 2.7.8 was built with visual c++ 2008 64-bit compiler, can I have the following mix a) my python extension built with VC2008 64-bit(to match python itself) b) 64-bit boost.python dll built with VC2010 64-bit c) python 64-bit, built itself with VC2008 64-bit? I've noticed that boost.python dll depends on python dll and that's why I'm quite worried about the mix. Appreciating your insights.

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[boost/config] BOOST_LIKELY argument requirements
by Stephan Bergmann 25 Sep '14

25 Sep '14

Looking at the definition of BOOST_LIKELY as #define BOOST_LIKELY(x) __builtin_expect(x, 1) in boost/config/compiler/{clang,intel,gcc}.hpp, and given that at lest the GCC and Clang __builtin_expect has a first parameter of type long, I wonder (1) whether it would be better to define it as #define BOOST_LIKELY(x) __builtin_expect(bool(x), 1) so that > $ cat test.cc > #include "boost/config.hpp" > #include "boost/logic/tribool.hpp" > int f(boost::tribool b1, boost::tribool b2) { > if (b1) return 1; > else if (BOOST_LIKELY(b2)) return 2; > else return 3; > } > > $ g++ -c test.cc > In file included from .../boost_1_56_0/boost/config.hpp:39:0, > from test.cc:1: > test.cc: In function ‘int f(boost::logic::tribool, boost::logic::tribool)’: > .../boost_1_56_0/boost/config/compiler/gcc.hpp:90:46: error: cannot convert ‘boost::logic::tribool’ to ‘long int’ for argument ‘1’ to ‘long int __builtin_expect(long int, long int)’ > #define BOOST_LIKELY(x) __builtin_expect(x, 1) > ^ > test.cc:5:14: note: in expansion of macro ‘BOOST_LIKELY’ > else if (BOOST_LIKELY(b2)) return 2; > ^ would not fail (effectively changing the requirement for the argument to BOOST_LIKELY from "[the] expression should result in a boolean value" to "it should be contextually convertible to bool"). (2) if not that, whether to at least wrap the expansion of x in parentheses, #define BOOST_LIKELY(x) __builtin_expect((x), 1) Stephan

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[assign][ptr_container] Exception safety of ptr_list_of, ptr_push_back, ptr_map_insert, etc.
by Aaron Levy 25 Sep '14

25 Sep '14

I am trying to understand how ptr_list_of or ptr_push_back provide more exception safety. I can write something like: boost::ptr_vector<Foo> vec; push_back(vec)(new Foo)(new Foo); Is the order of evaluation of the two "new Foo" expressions indeterminate here? If not, then if the second new throws, the destructor of vec should be invoked. The Foo object allocated by the first new and now part of vec should also get released as part of that. -- Aaron Levy aaron.levy(a)yandex.com

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[Log] reversed file rotation order...
by Ovanes Markarian 24 Sep '14

24 Sep '14

Hi *, We use file rotation with boost log, since I work more and with Python I use Python's logging as well. One interesting feature I observed was that Python's logger does reversed file rotation. Is that sort of feature implemented with boost::log library? In boost the rotation is: whatever_0.log < oldest file whatever_1.log whatever_2.log < newest file In Python the rotation order is: whatever_0.log < newest file whatever_1.log whatever_2.log < oldest file I think this is a very cool how Python does it, since I am able to endlessly "tail" in the shell the log file: tail -f whatever_0.log will not stop until I cancel the tail operation. With boot it is like, logger writes a new file and tail hangs with the file which is no longer written. This is a bit unusable and confusing. Would be great if that'd be possible in boost. Thanks, Ovanes

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Problems Linking with Boost Serialization
by Isaac Lascasas 24 Sep '14

24 Sep '14

I have found this on boost 1.56 with msvc12: Error 119 error LNK2005: "bool __cdecl boost::archive::detail::is_whitespace<char>(char)" (??$is_whitespace@D @detail@archive@boost@@YA_ND@Z) already defined in libboost_wserialization-vc120-mt-1_56.lib(basic_text_wiprimitive.obj) C:\supernova\sb6\src\supernova_clr\libboost_serialization-vc120-mt-1_56.lib(basic_text_iprimitive.obj) Error 120 error LNK2005: "bool __cdecl boost::archive::detail::is_whitespace<wchar_t>(wchar_t)" (??$is_whitespace@ _W@detail@archive@boost@@YA_N_W@Z) already defined in libboost_wserialization-vc120-mt-1_56.lib(basic_text_wiprimitive.obj) C:\supernova\sb6\src\supernova_clr\libboost_serialization-vc120-mt-1_56.lib(basic_text_iprimitive.obj) This code used to link fine with previous boost versions. Now it looks like you can't use both archive and warchive at the same time. I'm using xml warchives for serializing in my code. Regards. Isaac Lascasas.

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