July 2013 - Boost - lists.preview.boost.org

Boost 1.54 build problem: --without-context not honoured?
by Steve M. Robbins 11 Aug '13

11 Aug '13

Hi, I'm digging into a build problem and noticed that even though I specify "./bjam --without-context", Boost.Context is still built! The bjam configuration output states that Context is not to be built: Component configuration: - atomic : building - chrono : building - context : not building - coroutine : building - date_time : building - exception : building But it is built nonetheless. This causes a build failure for architectures which are not supported; see build log [1]. Compare that to the build for 1.53 [2] which works fine. I've diffed the libs/context directory between 1.53 and 1.54 and nothing jumps out at me as the cause. Has anyone noticed and fixed this already? Thanks, -Steve [1] https://buildd.debian.org/status/fetch.php?pkg=boost1.54&arch=ia64&ver=1.54… [2] https://buildd.debian.org/status/fetch.php?pkg=boost1.53&arch=ia64&ver=1.53…

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[boost/spirit] numeric policy
by Brian Schrom 07 Aug '13

07 Aug '13

I've had the case where I needed to retain formatting information for a number (general, fixed, scientific) and was nicely accomplished by extending the policy, but needed to have a begin_parse() and end_parse() for the policy to be complete. It seems that it makes some sense or is this accomplished another way? Maybe something to consider for policies in general? Index: qi/numeric/real_policies.hpp =================================================================== --- qi/numeric/real_policies.hpp (revision 85166) +++ qi/numeric/real_policies.hpp (working copy) @@ -28,6 +28,18 @@ static bool const allow_trailing_dot = true; static bool const expect_dot = false; + template <typename Attribute> + static void + begin_parse(Attribute& attr_) + { + } + + template <typename Attribute> + static void + end_parse(Attribute& attr_,bool /* result */) + { + } + template <typename Iterator> static bool parse_sign(Iterator& /*first*/, Iterator const& /*last*/) Index: qi/numeric/detail/real_impl.hpp =================================================================== --- qi/numeric/detail/real_impl.hpp (revision 85166) +++ qi/numeric/detail/real_impl.hpp (working copy) @@ -133,6 +133,7 @@ parse(Iterator& first, Iterator const& last, Attribute& attr, RealPolicies const& p) { + p.begin_parse(attr); if (first == last) return false; Iterator save = first; @@ -257,6 +258,7 @@ // If we got a negative sign, negate the number traits::assign_to(traits::negate(neg, n), attr); + p.end_parse(attr, true); // maybe this should return a bool and be the return value? // Success!!! return true; }

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[intrusive] Compilation problem with gcc 4.7
by Hartmut Kaiser 07 Aug '13

07 Aug '13

In code which compiled just fine I'm now seeing: In file included from /opt/boost/trunk-debug/boost/intrusive/slist_hook.hpp:24:0, from /opt/boost/trunk-debug/boost/intrusive/slist.hpp:21, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/hpx/lcos/local/mu tex.hpp:23, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/hpx/runtime/compo nents/server/wrapper_heap.hpp:20, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/hpx/runtime/compo nents/server/managed_component_base.hpp:13, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/hpx/lcos/base_lco .hpp:12, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/hpx/lcos/base_lco _with_value.hpp:11, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/hpx/performance_c ounters/counters.hpp:12, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/hpx/runtime/compo nents/server/runtime_support.hpp:32, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/hpx/runtime.hpp:1 2, from /opt/buildbot/slave/hpx_gcc47_x8664_boosttrunk_debug/build/src/hpx_main.cpp: 7: /opt/boost/trunk-debug/boost/intrusive/detail/generic_hook.hpp: At global scope: /opt/boost/trunk-debug/boost/intrusive/detail/generic_hook.hpp:134:55: error: declaration of typedef struct boost::intrusive::hooktags<typename GetNodeAlgorithms::type::node_traits, Tag, LinkMode, BaseHookType> boost::intrusive::generic_hook<GetNodeAlgorithms, Tag, LinkMode, BaseHookType>::hooktags [-fpermissive] /opt/boost/trunk-debug/boost/intrusive/detail/generic_hook.hpp:84:8: error: changes meaning of hooktags from struct boost::intrusive::hooktags<typename GetNodeAlgorithms::type::node_traits, Tag, LinkMode, BaseHookType> [-fpermissive] Ion, could you fix this, please? Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu

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[move] Documentation example typo.
by Jurko Gospodnetić 04 Aug '13

04 Aug '13

Hi. Just reporting a slight typo in boost::move library documentation's file_descriptor class example code for closing the OS file descriptor. It says: > if(!os_descr_) operating_system_close_file(os_descr_); in its destructor & assignment operator when it should in fact say: > if(os_descr_) operating_system_close_file(os_descr_); [notice the removed ! operator] Hope this helps. Best regards, Jurko Gospodnetić

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[asio] condition_variable for coroutine-powered ASIO
by TONGARI J 04 Aug '13

04 Aug '13

Hi, Since Boost 1.54, ASIO introduced yield_context, which is very helpful to alleviate the pain of writing async ops. Unlike multi-threading, with cooperative multi-tasking, generally we don't have to worry about synchronization, but we still need some sort of mechanism to sync the coroutines in cases like producer-consumer for waiting the data... While I haven't seen any sync tool for asio/coroutine, having a condition_variable or such may be very useful, what do you think? Attached is the poor-man's implementation...

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[utility] [swap] How about Boost.Move?
by Antony Polukhin 03 Aug '13

03 Aug '13

Hi, Sources of Boost.Variant have a swap implementation that takes advantage of move emulation. That code can be useful for Boost.Swap. The idea is not to use std::swap in case of ADL failure, but use a swap implementation that is aware of move emulation: namespace boost_swap_impl { namespace swap_move_emulated { template <typename T> inline void swap(T& lhs, T& rhs) { T tmp( boost::move(lhs) ); lhs = boost::move(rhs); rhs = boost::move(tmp); } } template<class T> void swap_impl(T& left, T& right) { //using namespace std;//use std::swap if argument dependent lookup fails using namespace boost_swap_impl::swap_move_emulated; swap(left,right); } // ... With that code types that use move emulation can be swapped faster and even move only types can be swapped. So, what do the community think about such optimization? -- Best regards, Antony Polukhin

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[git-help] New libraries?
by Rene Rivera 03 Aug '13

03 Aug '13

Today I checked in the new Predef library and I'm wondering, not just for it but in general, if this interim period of svn to git transition what happens to new libraries? Will they automatically show up in the git repos? What are the procedures if the new library is already, originally in git and modularized? Rene. -- -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim - grafikrobot/yahoo

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[predef] FYI..
by Rene Rivera 01 Aug '13

01 Aug '13

FYI.. to those that care.. I checked in changes to SVN to inject the Predef library into Boost. I say inject because the source is not actually in the SVN repo, it's external and still in github. But is being brought in through their SVN interface. Some testers have already runs the tests for it.. And at some point to be determined with some coordination with the community I will switch the "boost/detail/endian.hpp" header to point to the Predef compatibility equivalent... I suspect at the earliest one more week for that assuming no problems surface. Rene. -- -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim - grafikrobot/yahoo

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Re: [boost] [multimethods] Proposal: Open Multi-Methods
by Daryle Walker 01 Aug '13

01 Aug '13

//================================================================= From: Jean-Louis Leroy Sent: ‎Saturday‎, ‎July‎ ‎27‎, ‎2013 ‎8‎:‎26‎ ‎PM I am working on library that pretty much implements what Pirkelbauer, Solodkyy and Stroustrup describe in their paper "Open Multi-Methods for C++" - although there are some divergences. I have posted it on GitHub: https://github.com/jll63/multimethods. Please examine the files in the "examples" directory to get an idea of how to use it. [SNIP] The library is essentially feature complete (if anything ever is). I am now going to work on the documentation, a build system, some clean up and compatibility (I tested it only with g++ 4.7.2 only so far). Is there interest in the Boost community for this stuff? If yes, I will adapt it to the guidelines and submit it for formal review. Of course, suggestions are welcome. //================================================================= Are virtual base classes supported? Maybe “virtual_” should be renamed to “virtualize” or “virtualized,” to avoid having a trailing underscore in a non-member name. A good way to document is to write a Doxygen comment as you write your class, function, or macro prototype. It makes you have to think about what the public side of your code has to do. But looking at your “next.cpp” example, you should start with documenting the “selector,” “virtual_,” “MM_CLASS,” “MM_INIT,” “MULTIMETHOD,” “BEGIN_METHOD,” “END_METHOD,” and “initialize” items. Anything in your implementation classes that don’t have to be seen by public code can be make private. Non-public types can go in a detail namespace. Daryle W.

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[boost thread] Catching interrupted exception?
by Philip Bennefall 31 Jul '13

31 Jul '13

Hi all, I have a quick question regarding the interruption of Boost threads. I am making fairly heavy use of the interrupt method call of the thread class, and I am wondering whether I should be catching the boost::thread_interrupted exception from within my thread function? I currently do not and my program runs fine, but I am wondering whether this is defined behavior or whether I should always be catching the exception and returning from the function inside the handler? Kind regards, Philip Bennefall

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