April 2014 - Boost - lists.preview.boost.org

[asio] Bug: Handlers execute on the wrong strand.
by Greg Barron 04 Apr '14

04 Apr '14

Hi All, I would like to refer you to this bug report: https://svn.boost.org/trac/boost/ticket/9203 I won't paste the full contents of the bug report into this message. The executive summary is that the allocation algorithm for the implementation of asio::strand can and does allocate the implementation of an existing strand to strands that are subsequently allocated. This can have the effect that handlers wrapped in strand (b) will actually be executed on strand (a). I consider this to be a bug but if there is something that I'm misunderstanding about the operation of strands it would be great if you could help me clear it up. If the consensus is that this is a bug, what are the chances for it to be included in the 1.56 release? It is probably too late to be included in the 1.55 release. I've implemented a work around which could only be described as a hack and would be embarrassed to show it to anybody. But it gets me over my hump :). Thanks! -- Greg

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Re: [boost] Proposal: Vector-like container, which takes O(log(N)) for insert/erase (Glen Fernandes)
by Alexander Kuprijanov 04 Apr '14

04 Apr '14

Hi, again, I've implemented a container which should replace vector and have O(log(N)) for insert/delete. Please review. https://github.com/alexkupri/array/blob/master/description/description.txt The code is small, the description is verbose. Best regards, A.K.

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Boost.asio avoid the use of pipe
by Thomas Heller 03 Apr '14

03 Apr '14

Hi list, I'm currently trying to get a asio based software to run on CNK (a very lightweight kernel) which only implements a subset of the POSIX functions. One of the functions which is not implement is pipe. However, asio uses this in the epoll and select reactor. Is there any possibility to avoid that pipe is used? What options do I have? Cheers, Thomas

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[typeof] failed to compile under dependent context
by feverzsj 03 Apr '14

03 Apr '14

hi, list here is some code failed to compile with msvc9. Not sure if it is wrong use case or bug. template<class T> struct A { static T apply() { return T(); } }; template<class T> struct B { typedef BOOST_TYPEOF_TPL(A<T>::apply()) type; // error C2064: term does not evaluate to a function taking 0 arguments }; template<class T> BOOST_TYPEOF_TPL(A<T>::apply()) foo2() // error C2064: term does not evaluate to a function taking 0 arguments { } template<class T> void foo1() { BOOST_TYPEOF_TPL(A<T>::apply()) t; // ok } Regards, zsj -- View this message in context: http://boost.2283326.n4.nabble.com/boost-typeof-failed-to-compile-under-dep… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Boost.Geometry selected for MySQL
by Barend Gehrels 03 Apr '14

03 Apr '14

Hi, Recent news which is published this week (actually today): Boost.Geometry will be used for MySQL 's spatial database features. http://mysqlserverteam.com/building-mysql-with-boost/ This also means MySQL (server) will now use Boost libraries from now on. Regards, Barend

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[BGL] Visual Studio 12 finish_edge() failure, general BOOST_TTI_HAS_MEMBER_FUNCTION failure?
by Michael Behrns-Miller 01 Apr '14

01 Apr '14

Hello boost! In the BGL, finish_edge() is a visitor function of DFS, but it is optional. It is made optional via BOOST_TTI_HAS_MEMBER_FUNCTION. Here's how BGL defines it: ------------- BOOST_TTI_HAS_MEMBER_FUNCTION(finish_edge) template <bool IsCallable> struct do_call_finish_edge { template <typename E, typename G, typename Vis> static void call_finish_edge(Vis& vis, const E& e, const G& g) { vis.finish_edge(e, g); } }; template <> struct do_call_finish_edge<false> { template <typename E, typename G, typename Vis> static void call_finish_edge(Vis&, const E&, const G&) {} }; template <typename E, typename G, typename Vis> void call_finish_edge(Vis& vis, const E& e, const G& g) { // Only call if method exists do_call_finish_edge<has_member_function_finish_edge<Vis, void>::value>::call_finish_edge(vis, e, g); } ------------- In all my efforts, the Visual Studio 12 compiler fails to call finish_edge(). I've tried templated versions, direct versions, virtual versions, with and without const params, inline and not inline. In every case, VS says "code will not be hit, no executable code is associated with this line. possible causes: preprocessor directives or compiler/linker optimizations". I'm in debug mode with minimal optimizations, and there's no preprocessor wrapper. It's possible there's a problem with the way I'm calling it, but it happens when I use a simple example from another user. This ticket includes very simple sample code that should fire the finish_edge() function. It does not work for me using VS 12: https://svn.boost.org/trac/boost/ticket/9770 https://svn.boost.org/trac/boost/attachment/ticket/9770/test.cc I have a large project depending on the BGL, which has been great otherwise. I've coded a workaround by using the other non-optional visitor functions. But there are edge cases (sorry, no pun intended! ha) that fail with my workaround. The only possible solution is to get finish_edge() to fire. I'd like to do it the intended way, rather than rewrite BGL code to make finish_edge() non-optional. I'll go try this with a recent version of gcc now... Thanks for any input at all! Michael Behrns-Miller

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[git] Creating merge bases.
by Daniel James 01 Apr '14

01 Apr '14

Hi, After creating a merge base for iostreams last night, I thought I might do it for some other modules where I can find a good merge base. I won't do it for any modules with post-subversion commits on master, and I won't change any content without a pull request, so this shouldn't be disruptive. Does this sound okay? It should help anyone wishing to work on a module, as they can get a better idea of what hasn't been merged to master, and it should make it easier to merge changes. Daniel

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Proposal: Vector-like container, which takes O(log(N)) for insert/erase
by Alexander Kuprijanov 01 Apr '14

01 Apr '14

Hi, everybody! I've implemented a container, which has interface similar to vector and takes O(log(N)) for inserting/erasing. Shortly speaking, it has BTrees inside and intrusive leaves, and exploits idea of so-called "rope". I would like to name it alex_kupriianov_array (after myself) and add it to boost. Please tell me who is the coordinator of containers and what is the procedure of adding something to boost. If the community finds it useful, I'll add more features. Among them: 1) non-intrusive version of the container; 2) shallow/partial/lazy copying; if you copy an array and then modify small part of it (for example, beginning), it will keep different beginnings and common end; 3) bookmarks - sort of sticky iterators, which are sticky to a certain element, no matter if there are insertions/deletions before them. Contact me: alexkupri at gmail dot com

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