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

[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

2 6

[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

1 0

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

6 5