October 2008 - Boost-users - lists.preview.boost.org

tcp::sockets non-copyable, and threads
by Lindley M French 22 Oct '08

22 Oct '08

I'm trying to design a basic server, and I figured now would be a good time to get familiar with what Boost has to offer. However, I've already encountered a difficulty: boost::asio::ip::tcp::sockets are non-copyable. Therefore, I cannot simply acceptor.accept(socket), and then spawn a boost::thread on an object that uses that socket! If I pass a reference or pointer the socket must remain in scope, so it will need to by dynamically allocated....which doesn't seem right to me. I figure I'm probably missing something fundamental on the way boost is intended to work. Anyone care to enlighten me?

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Is there a FFT wrapper in boost?
by Peng Yu 22 Oct '08

22 Oct '08

Hi, FFTW is the fastest FFT library. But its interface is in C. I'm wondering if there is any ongoing project on FFT. Thanks, Peng

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Simple Filesystem Library Build and Usage
by df.trash 22 Oct '08

22 Oct '08

Using: Boost 1.36 Want to build static Filesystem Library for Windows and Linux. Right now I want to make sure the build is successful with the compilers we are using. I am a noobie with Boost and BJam, and am having difficulties building a test application for testing. Unfortunately, I'm dusting off my programming hat and learning to use all the appropriate tools again like compilers etc. I have read through much of the Boost instructions but still cannot seem to get the Filesystem library compiled as a static library and working with practical examples. Question: What is the simplest way to build a library to be used by my other source code out of the Filesystem Library on both Windows and Unix systems? And what is the simplest way to test that build? My first test is on Windows XP with Visual Studio Express 2005. *Attempt 1: *Create App with Visual Studio 2005 I ran the following from main Boost directory on the command line to create the library files: bjam debug --with-filesystem stage I then started a new Win32 Console Application in Visual Studio with the file_size.cpp test example. Under "Additional Include Directories" I put: "C:\Program Files\boost_1_36_0";"C:\Program Files\boost_1_36_0\stage\lib" I then tried to build the solution, and received the following error: LINK : fatal error LNK1104: cannot open file 'uuid.lib' *Attempt 2:* Create App with BJam I navigated to \libs\filesystem\src and created a Jamfile with the following: lib test : operations.cpp path.cpp portability.cpp utf8_codecvt_facet.cpp : <variant>debug <link>static ; I ran bjam in this folder which created a library: libtest-vc80-mt-gd-1_36.lib I copied the file to \libs\filesystem\example and created a Jamfile there with the following: exe FilesystemTest : file_size.cpp libtest-vc80-mt-gd-1_36.lib ; After running bjam in this folder, I received severael unresolved symbol erros like the following: file_size.obj : error LNK2019: unresolved external symbol "class boost::system::error_category const & __cdecl boost::system::get_system_category(void)" (?get_system_category@system @boost@@YAABVerror_category@12@XZ) referenced in function "public: __thiscall boost::system::error_code::error_code(void)" (??0error_code@system@boost@@QAE@XZ) Any help would be much appreciated!

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[graph] how to setup the mutable_queue?
by Fu Jie Huang 22 Oct '08

22 Oct '08

Hi, i'm trying to write a demo of prim/dijkstra algorithm (without using the stock code in BGL). but i'm lost at how to set up the priority queue with key updates (mutable queue, that is). how do i set up the distance map? or should the distance be the property of each vertex? and internally, how is distances of vertices maintained? thanks

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Need help with using Boost::Serialization on AmD64, Windows, MSVC 8.0
by Sahib Aulakh 22 Oct '08

22 Oct '08

I am building boost using the following command; this is done from the command window of MSVC 2005. \boost-jam-3.1.16-1-ntx86\bjam --build-dir=c:\boost-build --toolset=msvc --build-type=complete --address-model=64 The intention is to build for amd64 target. Is this the right command? Should toolset be specified as "msvc-8.0_64"? I am trying to use serialization library but keep getting linker errors like the following: 1>d:\source\ux_a_2\private\frontend\fex\search\searchconfigcontainer.obj : error LNK2019: unresolved external symbol "public: __cdecl boost::archive::basic_binary_oprimitive<class boost::archive::binary_oarchive,char,struct std::char_traits<char> >::~basic_binary_oprimitive<class boost::archive::binary_oarchive,char,struct std::char_traits<char> >(void)" (??1?$basic_binary_oprimitive@Vbinary_oarchive@archive@boost@@DU?$char_traits@D@std@@@archive@boost@@QEAA@XZ) referenced in function "public: __cdecl boost::archive::binary_oarchive_impl<class boost::archive::binary_oarchive,char,struct std::char_traits<char> >::~binary_oarchive_impl<class boost::archive::binary_oarchive,char,struct std::char_traits<char> >(void)" (??1?$binary_oarchive_impl@Vbinary_oarchive@archive@boost@@DU?$char_traits@D@std@@@archive@boost@@QEAA@XZ) There seems to be some internet chatter related to this at http://www.nabble.com/using-boost-in-x64-app-td19804910.html. However, I have been unable to make this thing work. If I create a standalone project in VC and use serialization code then it works all fine; however, the standalone code was written in 32bit mode. I will appreciate any clues anyone can provide. Thanks.

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Help with split_iterator, iterator_range and strings
by Jeffrey C. Jacobs 22 Oct '08

22 Oct '08

I am trying to write an adaptor function that takes a string and a list of character delimiters and populates an output iterator with the result. Specifically, this is what I have: using boost::algorithm::make_split_iterator; using boost::algorithm::split_iterator; using boost::iterator_range; using boost::copy_range; using boost::algorithm::is_any_of; using boost::algorithm::token_finder; template <typename E, typename T, typename A, typename D, typename OutIt> inline OutIt split_and_copy(const std::basic_string<E, T, A> &source, const D &delimeters, OutIt out) { typedef std::basic_string<E, T, A> mystring; typedef split_iterator<mystring::const_iterator> SplitIt; typedef iterator_range<mystring::const_iterator> RangeIt; const SplitIt b = make_split_iterator(source, token_finder(is_any_of(delimeters))); const SplitIt e; return std::transform(b, e, out, copy_range<mystring, RangeIt>); } This compiles but strikes me as a bit verbose. I mean, am I missing something visa-vi the proper interaction of split_iterator, iterator_range and the container they are splitting and making a range of? I believe since b is a split_iterator type, that *b is of type iterator_range, is this not correct? The templates would be as I listed for SplitIt and RangeIt, as I understand it. Now, originally I was hoping there would be an automatic conversion back from iterator_range to the ranged container, which would make a copy of the elements in the range and stick them into a container of the original type (in this case, string). Is there no conversion from iterator_range<mystring::const_iterator> back to mystring? You see, originally, I wanted to write: std::copy(b, e, out); But it seems there is no way around using std::transform with an explicit conversion from RangeIt to mystring with copy_range. Or am I wrong in that assumption? No, I don't want to use the split function since I don't want to populate the whole container, just write my entries to an output iterator; it's generic in that sense to allow for ostream_iterator or back_inserters or whatever. Also, is there some way to not have to explicitly provide the copy_range input type since that type is already known to be the same type as *b and *e? Thanks for any insight you might be able to offer! Jeffrey -- "Scan not a friend with a microscopic glass; you know his faults so let his foibles pass." -- Victorian Proverb, likely Sir Frank Crisp, 1st Baronet of Bungay ~,-;` The TimeHorse

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Is there a spatialIndex in boost?
by Peng Yu 22 Oct '08

22 Oct '08

Hi, Some message mentioned spatialindex. I'm wondering where the package homepage is at? Thanks, Peng

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Is there a way to generate the library names used by auto_link.hpp
by Patrick Harris 22 Oct '08

22 Oct '08

I'd like to be able to use the generated library names to automatically add a linker delay load option but the auto_link.hpp file undefs the lib name and some of the other defines used. Is there a supported way of getting the generated names other than duplicating and customising bits of the auto_link.hpp file? Thanks

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[graph] Newbie question: iterator shows vertices not added, always lo .. hi
by Chris Lott 21 Oct '08

21 Oct '08

Hi, I am new to the Boost graph library and trying to learn from examples in the documentation. I would like to ask about the simple vertex iterator's behavior. Below is sample code. In a nutshell, the program adds some edges to a Boost graph, then prints the vertices. The vertex numbers added are not contiguous: the loop basically adds edges between vertices 0, 1, 2, 6, and 7; no edges are added for vertices 3, 4, 5. Then I use a vertex iterator to show tine in- and out-degree of each vertex. My expectation was that the iterator would only show me the vertices for which I added edges, but instead it shows vertices from 0..7, essentially from the low value to the high value. This seems to be a feature, but I don't know where to look to find an explanation. Perhaps this behavior is dictated by my choices of data structures vecS? So far I have been relying on the online documentation, which I find to be quite difficult to use. For example, the web site doesn't seem to have a comprehensive index to Boost generic types and functions, just that alone would be an enormous help. Is the Boost book is (substantially?) better than using the online docs, or is it just the same content on paper? Please advise, thanks for your help. chris... -------- [code] #include <iostream> // for std::cout #include <utility> // for std::pair #include <algorithm> // for std::for_each #include <boost/graph/graph_traits.hpp> #include <boost/graph/adjacency_list.hpp> int /* GraphExample_ */ main(int,char*[]) { // create a typedef for the Graph type typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS> Graph; // Make convenient labels for the vertices enum { A, B, C, X, Y, Z, D, E, N }; const int num_vertices = N; typedef std::pair<int, int> Edge; Edge edge_array[] = { Edge(A,B), Edge(A,D), Edge(C,A), Edge(D,C), Edge(C,E), Edge(B,D), Edge(D,E) }; const int num_edges = sizeof(edge_array)/sizeof(edge_array[0]); // Declare a graph object with the specified number of vertices. Graph g(num_vertices); // add the edges to the graph object // Each vertex is an integer. for (int i = 0; i < num_edges; ++i) boost::add_edge(edge_array[i].first, edge_array[i].second, g); // Iterate through the vertices and print them out. // This iterator seems to be simply 0.. (largest vertex number). // Some vertices were never added as part of any edge, yet the // loop below shows them anyhow. typedef boost::graph_traits<Graph>::vertex_iterator vertex_iter; std::pair<vertex_iter, vertex_iter> vp; for (vp = vertices(g); vp.first != vp.second; ++vp.first) { vertex_iter iter = vp.first; boost::graph_traits<Graph>::vertex_descriptor v = *iter; int in = boost::in_degree(v, g); std::cout << "Vertex " << v << " has in degree " << in << std::endl; int out = boost::out_degree(v, g); std::cout << "Vertex " << v << " has out degree " << out << std::endl; } return 0; } [/code]

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[mutli_index] class reference available? / How to detect insertion failures
by Nick Martin 21 Oct '08

21 Oct '08

I recently discovered the boost multi_index library. It appears to be an incredible resource that I am really looking forward to using. Unfortunately, I have been frustrated by the documentation and unable to get much usable code written. The bulk of the information that has been helpful to me is in the examples. Branching out beyond what is specifically done in an example has proven to be difficult for me because of a lack of reference documentation. I am not an expert in reading templatized and type-defed code, so reading the headers themselves has been very time consuming. That led me to wonder if Doxygen-like documentation is available? For instance, the Asio library has a very nice reference available http://www.boost.org/doc/libs/1_36_0/doc/html/boost_asio/reference.html Looking at the TCP socket's connect method leads you here: http://www.boost.org/doc/libs/1_36_0/doc/html/boost_asio/reference/basic_st… Here I can see the parameters and return types and in general figure out how to use this class. Contrast that with multi_index. There doesn't appear to be comprehensive class reference documentation. I only figured out how to do simple tasks like inserting new items into the container by looking at the examples ( http://www.boost.org/doc/libs/1_36_0/libs/multi_index/example/basic.cpp) My specific question (which the examples don't seem to cover) is how to tell when insertion fails. What if the new item's unique key constraint fails? I have had many other, seemingly simple questions that I would hope could be answered in minutes or seconds that have turned into hours of trial and error and combing through example programs. What other resources are out there that I refer to in order to use this great library? Thanks, Nick

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