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[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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[align] [review] Pre-review comments
by Steven Watanabe 31 Mar '14

31 Mar '14

AMDG I saw the announcement of the review and decided to take a look at the library today. All the following is based on: commit 0d361143c18254efddacfd48775a2776ca7d5e11 Author: Glen Fernandes <glenfe(a)live.com> Date: Thu Mar 27 17:45:12 2014 -0700 Documentation: align: "alignment shall be a fundamental alignment value or an extended alignment value and a power of two." Please define these terms. Also warning: suggest parentheses around ‘and’ within ‘or’ [-Wparentheses] aligned_alloc: I notice that alignment is only required to be a power of two. Is there a reason this is different from align? aligned_allocator: template<class T, size_t Alignment = 1> class aligned_allocator; I'd really like to see the requirements on Alignment written out somewhere, even if we can deduce it from the fact that it calls aligned_alloc. Also, does the standard guarantee that all alignments are powers of 2? Otherwise lcm(2^k, alignof(T)) is not guaranteed to be a power of 2. If it is guaranteed, then lcm(2^k, alignof(T)) == max(2^k, alignof(T)) This is probably worth noting. aligned_allocator notes: "Specifying minimum alignment is generally only suitable for containers such as vector and undesirable with other, node-based, containers." I had to think about this for a few seconds. If you're going to say this, you should probably explain why. aligned_allocator_adaptor: template<class A> aligned_allocator_adaptor(A&& alloc); Not explicit? Should aligned_allocator_adaptor really be convertible from anything? template<class U> aligned_allocator_adaptor(const aligned_allocator_adaptor<U, Alignment>& other); Requires: Allocator shall be constructible from A. Copy/paste error. There is no A here. pointer allocate(size_type n, const_void_pointer hint = 0); Requires: hint is a value obtained by calling allocate(), or else nullptr. Calling allocate on what? Not just this object, but any equivalent aligned_allocator_adaptor, should work. aligned_allocator_adaptor notes "This adaptor class can be used with any C++11 or C++03 allocator including those allocators whose pointer type is a smart pointer." I don't see how this could possibly work with a smart pointer when aligned_allocator_adaptor explicitly uses raw pointers. Your tests pass for we with msvc 9.0-12.0, gcc-mingw-4.6.2, and clang-3.4 on Windows and with gcc 4.7.2 on Linux. aligned_allocator.hpp:100 aligned_free(memory); This is vulnerable to ADL if std::aligned_free is ever created (or my_ns::aligned_free for that matter). (Note that the corresponding aligned_alloc is safe becase std::size_t has no associated namespaces) aligned_allocator.hpp:104 enum { Size = static_cast<std::size_t>(-1) / sizeof(T) }; There's absolutely no reason to use an enum as far as I can see. You can just return this value. aligned_allocator.hpp:139 memory->~U(); I seem to recall msvc warning that memory is unused in cases like this. You may need to supress the warning. detail/align.hpp:28 if (n1 <= space && size <= space - n1) You might add a comment about avoiding overflow, so that no one is tempted to refactor it into an simpler "equivalent" test. test/Jamfile.v2: This is a lot more verbose than it needs to be. Try just: import testing ; run align_test.cpp ; run aligned_alloc_test.cpp ; ... test-suite is obsolete (it just groups all the targets under a single name, which is completely pointless when that's all you have in the Jamfile) and the braces just create a compound statement (like in C++) test/align_test.cpp: You need to test the following: - There is not enough space in the buffer. - In particular, you need to validate the exact boundaries where align starts to return 0. test/aligned_alloc_test.cpp: You need tests for the following conditions: - size == 0 - size < alignment - size > alignment && gcd(size, alignment) != alignment - the allocation fails because size is too large. - Also write to the allocated memory to (hopefully) verify that the data structure used by aligned_alloc is safely outside this region. test/aligned_allocator_adaptor_test.cpp: You're only testing allocate/deallocate. You also need tests for the other members. - rebind - copy constructor/copy assignment operator - construct/destroy - allocate with a hint - allocate with 0 size test/aligned_allocator_test.cpp: same as aligned_allocator_adaptor_test.cpp. test/is_aligned_test.cpp You need tests for: - is_aligned returns false. Your entire test suite would pass with bool is_aligned(...) { return true; } In Christ, Steven Watanabe

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symbolic link missing in modular-boost/boost/numeric
by David Bellot 31 Mar '14

31 Mar '14

Hi, it seems the symbolic link to ublas is missing in "modular-boost"/boost/numeric. I would be very grateful if someone with more admin rights than me could add it and commit it please ? Many thanks. Best regards, David

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