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Negative Cycle Detection Code
by Paul De La Musica 02 Nov '08

02 Nov '08

Hi, Is there any negative cycle detection code in the public domain? We would prefer BGL based code but LEDA is fine too. Thanks, Paul

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[type-traits] virtual function type trait check
by Chris 02 Nov '08

02 Nov '08

I was wondering if it were possible to make a is_virtual_function type trait check. Example: class B { public: virtual void complicatedFunction() { } }; class D : public B { public: void complicatedFnction() { static_assert(**check if D::complicatedFnction() is virtual **); // notice the misspelling. } };

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Building software with Boost
by Lasse Kärkkäinen 01 Nov '08

01 Nov '08

Hi, There are two questions for which I have found no answers: 1. When exactly are -mt (multithreaded) versions of the libraries needed? 2. Boost.System was added in 1.35 and apparently some of the old libraries also depend on it in new Boost versions. Are the inter-library dependencies of Boost actually documented somewhere, or does one need to guess? I need this information in order to write a new FindBoost script for CMake.

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Boost.Build doc changes
by Vladimir Prus 01 Nov '08

01 Nov '08

FYI, I've committed, and then merged to release branch, the following doc changes: 1. https://svn.boost.org/trac/boost/changeset/49508, which makes Jamroot list some of the properties that user might want to specify. 2. https://svn.boost.org/trac/boost/changeset/49511, which revises the Boost.Build docs on configuration and invocation. The problem with the previous docs was that the information a newbie user (of C++ Boost, or of any other project) would have to look at a bunch of pages to understand everything -- e.g. command line syntax was split into two pages, and there was huge unlinked list of features on yet another page. Now, the "Configuration" and "Invocation" sections are supposed to say mostly everything needed for a quickstart. I also though that getting started needs update, to link to those pages, and to use toolset= as opposed to --toolset=, but it does not seem like there's time for that. - Volodya -- Vladimir Prus http://vladimir_prus.blogspot.com Boost.Build V2: http://boost.org/boost-build2

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[date_time] Major commit in trunk
by Andrey Semashev 01 Nov '08

01 Nov '08

I have committed my changes to the DateTime library in trunk (revision 49506). If anyone starts experiencing problems with it, please, let me know.

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Re: [boost] [Boost-commit] svn:boost r49504 - trunk/tools/build/v2/tools
by Juergen Hunold 01 Nov '08

01 Nov '08

HI Volodya ! Are you sure that removing gcc flavour was intended ? On Saturday 01 November 2008 09:21:57 ghost(a)cs.msu.su wrote: > Modified: trunk/tools/build/v2/tools/gcc.jam > =========================================================================== >=== --- trunk/tools/build/v2/tools/gcc.jam (original) > +++ trunk/tools/build/v2/tools/gcc.jam 2008-11-01 04:21:56 EDT (Sat, 01 > Nov 2008) @@ -34,6 +34,7 @@ > > > feature.extend toolset : gcc ; > +# feature.subfeature toolset gcc : flavor : : optional ; > > toolset.inherit-generators gcc : unix : unix.link unix.link.dll ; > toolset.inherit-flags gcc : unix ; > @@ -130,6 +131,7 @@ > condition = [ common.check-init-parameters gcc > : version $(version) > ] ; > + condition = $(condition) ; #/<toolset-gcc:flavor> ; > } > Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! Ingenieurgesellschaft für * voice: ++49 511 262926 57 ! Verkehrs- und Eisenbahnwesen mbH * fax : ++49 511 262926 99 ! Lister Straße 15 * juergen.hunold(a)ivembh.de ! www.ivembh.de * * Geschäftsführer: ! Sitz des Unternehmens: Hannover * Prof. Dr.-Ing. Thomas Siefer ! Amtsgericht Hannover, HRB 56965 * PD Dr.-Ing. Alfons Radtke !

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Style Guideline
by Robert Jones 31 Oct '08

31 Oct '08

Writing the kind of code that you see in the Boost libraries is something of a step change from the day-to-day production code that I write, and I suspect most of us write (Joel, Eric, Dave, Peter and others excepted of course! :-) ), and writing it, I find, is a rather different matter from reading it and broadly understanding it! So,....enable_if.... Is enable_if intended only to include or exclude complementary instantiations of different templates from the possible set, or also to control whether a particular instantiation is available at all? Say I have a class which I want to be able to instantiate only for vectors. Is it sensible to create an is_vector<> template and then use enable_if, or should I simply allow instantiation to fail when the code uses some aspect of vectors which is specific to vectors? Does the situation change if it is vectors or lists that are permissible? Or if it's anything with begin() & end() defined? Or am I making a complete hash of this, and ought to be thinking in a different paradigm? Thanks in advance. - Rob.

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[Timer] Inconsistent behaviour
by Jordans, R. 31 Oct '08

31 Oct '08

Hey all, I was looking at Boost.Timer and I noticed that it shows different results when it's used in a threaded program on Windows or Unix machines. A closer inspection revealed that it uses clock() to do it's timings. Digging a bit deeper I found that clock() is specified differently on Windows than it is in my Linux man-page. On windows it counts 'wall clock' time, basically what I'd expect from a class named timer but on Linux it counts CPU time. Thus it will give the result for completely different concepts of time elapsed depending on my system. Two questions; 1) is there a good way to solve this, 2) if not, could it at least be noted in the documentation. Thanks, Roel

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first Visual Studio 2010 CTP is out, c++0x
by Cory Nelson 31 Oct '08

31 Oct '08

In case anyone missed it, a VS10 CTP is out with partial 0x support (lambda, rvalue, static assert, and "auto"), better intellisense, and a modern c++ parallel library. http://www.microsoft.com/downloads/details.aspx?familyid=922b4655-93d0-4476… -- Cory Nelson

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boost::filesystem request
by Jorge Lodos Vigil 31 Oct '08

31 Oct '08

Hi The Traits classes for basic_path provided in the filesystem library (path_traits and wpath_traits) are good enough to be used as default values for basic_path in most cases. However, since they are independent structs, they can not be used to instantiate a basic_path with a single String template parameter. I would like to write: typedef basic_string<char> string_t; typedef fs::basic_path<string_t, fs::basic_path_traits<string_t> > path_t; Currently we are forced to write in our code something as: template <typename String> struct path_traits {}; template <> struct path_traits<std::string> { typedef boost::filesystem::path_traits traits_t; }; template <> struct path_traits<std::wstring> { typedef boost::filesystem::wpath_traits traits_t; }; typedef std::basic_string<CharT> string_t; typedef boost::filesystem::basic_path<string_t, typename path_traits<string_t>::traits_t > path_t; I underestand it is important to emphasize that Traits classes have nothing to do with String classes in path instantiations, so my question is: Is it reasonable to ask that path traits classes provided in the library would be implemented as template specializations instead of separate classes? Thanks in advance. Best regards Jorge

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