- Boost-users - lists.boost.org

Re: [Boost-users] Re: lambda dereferencing pointer
by Sean DeNigris 05 Apr '05

05 Apr '05

Sorry my man, include boost/lambda/bind.hpp also.

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How to represent bipartite graphs ?
by Markus Krosche 05 Apr '05

05 Apr '05

Hello together, in my software I have to represent bipartite graphs, in my case petri nets (two disjoint sets - the places and the transitions - and only links between elements of the disjoint sets). I would like to use BGL for this purpose, but I did not find a "nice" solution for this problem. I am quit new to BGL and the only way I see is representing the two types of vertices inside a vertex-property. A better way would be to have two types of vertex properties, but I think this is not possible. Is there anyone who has a solution or an idea for this kind of problem? Thanks and best regards Markus

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Re: [Boost-users] lambda dereferencing pointer
by Sean DeNigris 05 Apr '05

05 Apr '05

> std::partition( m_files.begin(), m_files.end(), > boost::bind( &boost::filesystem::is_directory, > *boost::lambda::_1 ) ); You are using bind from Boost.bind and _1 from Boost.lambda. If you change to boost::lambda::bind it will compile. See http://www.boost.org/doc/html/lambda/s08.html#id547254 for more detail. - Sean

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C++ Template Metaprogramming Answers Page (was: EX 2.1)
by Dave Gomboc 05 Apr '05

05 Apr '05

> > Low-tech solution: "scroll down for next hint" "scroll down for > > solution" > > If you're willing to give up on the goal of "one page per exercise," > and would like to go instead with a finer-grained structure, we can > accomplish any restructuring you wish through the Wiki's > administrative interface; just let us know. Show the first hint, with a link. Clicking the link shows everything the same, but the link is replaced with a second hint, and a third link appears. Repeat until out of hints -- in which case no link appears. For example: http://www.uhs-hints.com/uhsweb/hints/halflife2/8.php Dave

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lambda dereferencing pointer
by Matthias Kaeppler 05 Apr '05

05 Apr '05

Consider m_files to be a vector of pointers to boost::filesystem::pathS: std::partition( m_files.begin(), m_files.end(), boost::bind( &boost::filesystem::is_directory, *boost::lambda::_1 ) ); I want to invoke is_directory on the pointees. The error message is extremely long-winded and expands over several pages. I suppose you don't want to see it :) But maybe you can see immediately what I'm doing wrong? -- Matthias Kaeppler

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lambda dereferencing pointer
by Matthias Kaeppler 05 Apr '05

05 Apr '05

Hello, consider m_files to be a vector of pointers to boost::filesystem::pathS: std::partition( m_files.begin(), m_files.end(), boost::bind( &boost::filesystem::is_directory, *boost::lambda::_1 ) ); I want to invoke is_directory on the pointees. The error message is extremely long-winded and expands over several pages. I suppose you don't want to see it :) But maybe you can see immediately what I'm doing wrong? -- Matthias Kaeppler

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[typeof] MSVC-specific implementation added
by Arkadiy Vertleyb 05 Apr '05

05 Apr '05

Hi all, The recently discussed MSVC-specific trick, by Igor Chesnokov, has been added to the BOOST_TYPEOF submission. As a reminder, this implementation compiles much faster, and doesn't require type/template registration. This implementation covers VC6.5/7.0/7.1, but not VC8.0 (where the loophole seems to have been fixed). Please take it in the Boost sandbox file vault, http://boost-sandbox.sourceforge.net/vault/, typeof.zip. Regards, Arkadiy

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[typeof] MSVC-specific implementation added
by Arkadiy Vertleyb 05 Apr '05

05 Apr '05

Hi all, The recently discussed MSVC-specific trick, by Igor Chesnokov, has been added to the BOOST_TYPEOF submission. As a reminder, this implementation compiles much faster, and doesn't require type/template registration. This implementation covers VC6.5/7.0/7.1, but not VC8.0 (where the loophole seems to have been fixed). Please take it in the Boost sandbox file vault, http://boost-sandbox.sourceforge.net/vault/, typeof.zip. Regards, Arkadiy

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[serialization] Problem serializing uninitialized bools
by Andrew B 05 Apr '05

05 Apr '05

Let me first say "thanks" to everyone involved in Boost, particularly the serialization library. I am continuously impressed with the quality of this project. That said, I think I've encountered an issue that I would label as a bug, but perhaps there's something I'm missing. The following code throws/fails in Visual C++ 7.1 debug build. void boolTest() { bool uninitializedBool1, uninitializedBool2; std::ofstream ofs( "booltest.txt" ); boost::archive::text_oarchive oa( ofs, boost::archive::no_header ); oa << uninitializedBool1; oa << uninitializedBool2; ofs.close(); std::ifstream ifs( "booltest.txt" ); boost::archive::text_iarchive ia( ifs, boost::archive::no_header ); ia >> uninitializedBool1; ia >> uninitializedBool2; ifs.close(); } The reason is clear if you look at the contents of booltest.txt: 204 204 Since those bools are uninitialized, VC has written its standard "garbage" to their contents, which gets serialized as a value other than 0 or 1, which is what what the text_iarchive / ifstream would expect to see. I'm not sure if there's a philosophical opposition to supporting serializing uninitialized data, but the other primitives seem to work, and in my experience, it's not unusual to not initialize ever member of a struct before needing to serialize it. Thanks for your time, Andrew

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boost::mpl::transform
by Lemings, Eric B. (Contr) 05 Apr '05

05 Apr '05

What is the result type of transform if the algorithm is given two sequences of different sizes? Thanks, Eric.

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