January 2012 - Boost - lists.preview.boost.org

[strings][unicode] Proposals for Improved String Interoperability in a Unicode World
by Beman Dawes 31 Jan '12

31 Jan '12

Beman.github.com/string-interoperability/interop_white_paper.html describes Boost components intended to ease string interoperability in general and Unicode string interoperability in particular. These proposals are the Boost version of the TR2 proposals made in N3336, Adapting Standard Library Strings and I/O to a Unicode World. See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3336.html. I'm very interested in hearing comments about either the Boost or the TR2 proposal. Are these useful additions? Is there a better way to achieve the same easy interoperability goals? Where is the best home for the Boost proposals? A separate library? Part of some existing library? Are these proposals orthogonal to the need for deeper Unicode functionality, such as Mathias Gaunard's Unicode components? --Beman

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[c++TR2] N3334, Proposing array_ref<T> and string_ref
by Beman Dawes 31 Jan '12

31 Jan '12

On Sat, Jan 28, 2012 at 8:12 PM, Mathias Gaunard <mathias.gaunard(a)ens-lyon.org> wrote: > On 01/28/2012 05:46 PM, Beman Dawes wrote: >> >> Beman.github.com/string-interoperability/interop_white_paper.html >> describes Boost components intended to ease string interoperability in >> general and Unicode string interoperability in particular. >> >> These proposals are the Boost version of the TR2 proposals made in >> N3336, Adapting Standard Library Strings and I/O to a Unicode World. >> See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3336.html. >> >> I'm very interested in hearing comments about either the Boost or the >> TR2 proposal. Are these useful additions? Is there a better way to >> achieve the same easy interoperability goals? > > > I think you should consider the points being made in N3334. See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3334.html While this proposal isn't from Boost, it impacts interests of Boost developers enough that I think it is worth discussing here as a separate topic. Mathias continues: > While that proposal is in my opinion not good enough, it raises an important > issue that is often present with std::string-based or similar designs. > > A function that takes a std::string, or a boost::filesystem::path for that > matter, necessarily causes the [caller] to copy the data into a heap-allocated > buffer, even if there is no need to. Some std library string implementations avoid the heap allocation for small strings, but still there is an unnecessary copy happening even in those implementations. Your point is well taken and I've often worried about it with boost::filesystem::path. > Use of the range concept would solve that issue, but then that requires > making the function a template. A type-erased range would be possible, but > that has significant performance overhead. > a string_ref or path_ref is maybe the lesser evil. One of my blink reactions is that array_ref<T> and basic_string_ref<charT, traits> are range generators and I was a bit surprised to see the implementation was a pointer and length rather than two pointers. Or better yet, two iterators or an explicit range component. With iterators, a basic_string_ref could do encoding conversions on-the-fly without need of temporary strings. But I have no idea if that is workable or actually is better. What do other Boosters think? --Beman --Beman

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[conversion] Lot of 'long long' warnings
by sguazt 31 Jan '12

31 Jan '12

Hello, When compiling with GCC 4.6.2 with flags '-Wall -Wextra -ansi -pedantic', I get the following warnings concerning the use of the 'long long' type under the ISO C++98: boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:16:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:21:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:28:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:33:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:40:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:45:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:52:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:57:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:64:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:69:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:76:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:81:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:88:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:93:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:100:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:105:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:112:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:117:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:124:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:129:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:136:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:141:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:148:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:153:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:160:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:165:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:172:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:177:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:184:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:189:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:196:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:201:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:208:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:213:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:220:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:225:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:232:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:237:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:244:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:249:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:256:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:261:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:268:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:273:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:280:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:285:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:292:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:297:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:303:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:304:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:309:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:315:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:316:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:321:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:327:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:328:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:333:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:339:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:340:13: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] boost-trunk/boost/numeric/conversion/detail/preprocessed/numeric_cast_traits_long_long.hpp:345:23: warning: ISO C++ 1998 does not support 'long long' [-Wlong-long] Could you fix them? Thank you very much. Best, -- Marco

3 3

[context] Boost.Context library accepted
by Giovanni Piero Deretta 31 Jan '12

31 Jan '12

Hi All, The mini-review of the boost.context library from Oliver Kowalke ended two weeks ago. After a slow start, three reviews were eventually submitted, all positive. For a mini-review, I think this is enough and, as the review manager, I'm happy to announce that Boost.Context is accepted as an official boost library. Congratulations to Oliver for this achievement and thanks for submitting an useful library to Boost. Most of the review discussions were around the quality of the documentation and some misunderstanding of some details of the library. While the documentation has greatly improved since the first review, I think that it can be still improved. I encourage Oliver to seek the help of some native English speaker to help copy edit the docs. Finally I would like to thanks everybody that participated in the review discussions and in particular those that submitted reviews. regards, -- Giovanni Deretta,

2 1

Requesting a review of Metaparse
by Abel Sinkovics 31 Jan '12

31 Jan '12

Hi, I've created a version of Metaparse that depends on the Boost libraries only. I request this version of Metaparse be placed in the queue for formal review. The zipped source code can be found here: http://abel.web.elte.hu/metaparse/metaparse.zip The documentation can be found here: http://abel.web.elte.hu/metaparse/metaparse The library has been tested on the following compilers: - GCC 4.6 (with and without -std=c++0x) - GCC 3.4 - Clang 2.9 - Visual C++ 10 A quick summary: Metaparse is a library for constructing parsers parsing at compile-time based on template metaprogramming. The parsers built with the library take boost::mpl::strings as input and can produce - types - objects (types with public static members) - callable C++ functions (types with public static method) - template metafunction classes as output (based on the input being parsed). On compilers supporting constexpr the library provides the following syntactic sugar for writing the input of the parsers: BOOST_STRING("this is a string") The library can be used for implementing DSLs in C++, including DSLs making C++ template metaprogramming easier (see examples). Regards, Abel

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My non-system GCC doesn't link programs under b2
by Daryle Walker 30 Jan '12

30 Jan '12

I'm still using my 2002 PowerPC/G4 Mac with Mac OS X 10.4 (Tiger). I loaded GCC 4.6 (with multiprocessor options) onto it with MacPorts. I have a "user-config.jam" in my home folder like: //===using xsltproc : /opt/local/bin/xsltproc ; using boostbook : /opt/local/share/xsl/docbook-xsl/ : /opt/local/share/xml/docbook/4.2 ; using doxygen ; using darwin ;using gcc : 4.6 : g++-mp-4.6 : <cxxflags>-std=c++0x <cxxflags>-pthread ;//=== I've tested GCC-4.6 (with C++11 active) with a "Hello World!" program, so I know it works with single-file programs. I wanted to test "base_from_member" (part of Boost.Utility) and it worked with the default "darwin" target. (I ran "b2" in "BOOST_ROOT/libs/utility/test".) However, running "b2 toolset=gcc-4.6" ended in errors like: //===common.mkdir ../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6common.mkdir ../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6/debuggcc.compile.c++ ../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6/debug/base_from_member_test.o../base_from_member_test.cpp: In constructor 'bad_class::bad_class()':../base_from_member_test.cpp:129:21: warning: 'bad_class::x_' will be initialized after [-Wreorder]../base_from_member_test.cpp:510:39: warning: base 'base_class' [-Wreorder]../base_from_member_test.cpp:507:1: warning: when initialized here [-Wreorder]gcc.link ../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6/debug/base_from_member_test/usr/bin/ld: unknown flag: --start-groupcollect2: ld returned 1 exit status "g++-mp-4.6" -o "../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6/debug/base_from_member_test" -Wl,--start-group "../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6/debug/base_from_member_test.o" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -g ...failed gcc.link ../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6/debug/base_from_member_test......skipped <p../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6/debug>base_from_member_test.run for lack of <p../../../bin.v2/libs/utility/test/base_from_member_test.test/gcc-4.6/debug>base_from_member_test......failed updating 20 targets......skipped 40 targets......updated 126 targets...//=== GCC-4.6 compiles each C++ file into an object file just fine. The problem happens when linking various object and library files into an executable; whichever linker gets called (the system linker?) chokes on a "--start-group" flag. When I first started writing this message, I thought the problem was GCC-4.6 being too new for the linker, but maybe we have to tweak something in our Jam files instead. (Could it be the fact I downloaded the multiprocessor variant of GCC-4.6?) BTW, how do I specify that I only want to try out the base_from_member test without trying to build all other tests in the directory? Daryle W.

4 4

[thread] Can't use boost/thread/mutex.hpp without boost_system
by Artyom Beilis 30 Jan '12

30 Jan '12

Hello, The Boost.Thread version in trunk does not allow to use simple mutex as it was possible before: #include <boost/thread/mutex.hpp> #include <iostream> int main() { boost::mutex l; { boost::unique_lock<boost::mutex> g(l); std::cout << "Test" << std::endl; } } Was working fine without linking with 1.48 and 1.46 but now it fails with current trunk version requiring dependency on Boost.System. It breaks some code and breaks at least Boost.Locale. Is this change intentional or a bug? If it is intentional I'd like to know to fix Boost.Locale if not then is it possible to fix it. Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.sf.net/ CppDB - C++ SQL Connectivity: http://cppcms.sf.net/sql/cppdb/

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Re: [boost] [Boost-users] numeric_cast_traits/cstdint: request for fix in boost1.49
by John Maddock 30 Jan '12

30 Jan '12

>Currently HPUX/acc compiler fails in boost 1.48, because boost::int8_t was >being interpreted as a char, This causes duplicate class definition >in the file >./boost/numeric/conversion/detail/preprocessed/numeric_cast_traits.hpp >and hence many of compiled boost libs fail. Thanks for raising this on the list, I just posted these comments to the Trac ticket: "IMO this is the wrong fix: our code should make no assumptions about the actual type of uintXX_t etc. IMO the preprocessed headers are just plain wrong - you can't mix concrete types (char short etc) with typedefs (intXX_t) because you're just asking for problems with duplicate specializations. It has to be all real types throughout. BTW in addition to the two platforms mentioned above, this is also broken for Sun on Linux. Reassigning to the person who made these changes..." Not sure if we can fix this for 1.49, but you're right, it is a high priority. Hopefully Brandon Kohn is reading this as he made those changes? John.

5 9

[Boost.Asio] Asio is using Boost.Chrono for 1.49?
by Christian Hägele 30 Jan '12

30 Jan '12

Hello, as I looked through the changes for Boost.Asio with boost 1.49 I noticed that it looks like Boost.Chrono's steady_clock is used for timers (when std::chrono is not available). First of all that very nice, because steady_clock is not affected by change of the system-time. However I think there is a major problem on windows. On windows there are some problems with QueryPerformancecoutner in multi-processor systems (http://support.microsoft.com/kb/274323) There is also a comment in boost/chrono/system_clocks.hpp about this issue and no real solution provided. Is that problem solved by now? If not will the better choice be to stick with the old system-time implementation until std::chrono is supported on MSVC? Or is this problem rather a minor problem and can be ignored? Regards, Christian

1 0

[bjam] copy a file
by lcaminiti 30 Jan '12

30 Jan '12

Hello all, I'd have a Jamfile that has a "doc" rule to build documentation `bjam doc`. I'd like to program another rule "config_doc" inside the Jamfile that does the following: bjam config_doc: 1) Copy the file /etc/config.txt to ./ 2) Copy the file ./src/config.txt to /etc/ 3) Run the doc rule 4) Copy the file ./config.txt into /etc/ Where ./ is the current directory from where I'm running bjam. Ideally, I'd like 4) to be executed even if 3) fails. Is there a way to do this? Thanks a lot. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-bjam-copy-a-file-tp4321537p4321537… Sent from the Boost - Dev mailing list archive at Nabble.com.

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