January 2013 - Boost-users - lists.preview.boost.org

Identify cycles in a undirected graph
by NsPx 20 Aug '13

20 Aug '13

Hi all, I use undirected_dfs to detect all cycles in a undirected graph. I detect a cycle with DFSVisitor.back_edge(e,g) but how can I get the list of vertices defining this cycle ? Thanks by advance

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Is boost::this_thread::sleep_for interruption point?
by Serg Gulko 23 May '13

23 May '13

Hello! According to documentation(v 1.50.0) call boost::this_thread::sleep_for can be interrupted. For some reason this functionality not works for me. Here is code sample: //Simple thread function void Test::worker(int delay) { try { boost::this_thread::sleep_for(boost::chrono::milliseconds(delay)); cout << "Doing some work" << endl; } catch (boost::thread_interrupted const& e) { cout << "INTERRUPTED" << endl; } } //Far in the code boost::thread workerThread(boost::bind(&Test::worker, this, 1200)); boost::this_thread::sleep(boost::posix_time::milliseconds(30)); workerThread.interrupt(); boost::this_thread::sleep(boost::posix_time::milliseconds(1500)); I always getting 'Doing some work'... -- View this message in context: http://boost.2283326.n4.nabble.com/Is-boost-this-thread-sleep-for-interrupt… Sent from the Boost - Users mailing list archive at Nabble.com.

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Re: [Boost-users] [CMake] [boost][b2] Differenciate 32bit and 64 bit binaries when using CMake.
by Klaim - Joël Lamotte 16 Apr '13

16 Apr '13

Júlio Hoffimann said: > > I don't know if i understood correctly, but you can set the library > directory by hand, please refer to > /usr/share/cmake-<version>/Modules/FindBoost.cmake, in particular the > variable BOOST_LIBRARYDIR. On Thu, Oct 11, 2012 at 1:29 PM, Miller, Frank <FMiller(a)sjm.com> wrote: > A simple solution would be to install only the 64bit version of boost > into a new directory and change the environment variable to point there. > Then FindBoost will only be able to see the version you want. > Thanks, this will solve my immediate problem, but it don't solve it in general. (I will use it though, so thanks) I can't guarantee where the boost libraries are installed, that's why I use FindBoost. My current understanding is that boost don't have a specific default lib dir for different address models, which is the source of the problem as FindBoost script can't rely on a protocol to find these lib files. Am I correct? Joel Lamotte

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can't get first example in boost tutorial to work
by 7stud 11 Mar '13

11 Mar '13

I'm trying to install boost on mac osx 10.4.7. I followed the tutorial "Getting Started on Unix Variants" found here: http://www.boost.org/doc/libs/1_35_0/ more/getting_started/unix-variants.html Following the instructions in the tutorial, I installed boost in /usr/local as instructed, so my directory structure is: /usr/local/boost_1_34_1/boost But when I run the first example in the tutorial: #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; typedef std::istream_iterator<int> in; std::for_each(in(std::cin), in(), std::cout << (_1 * 3) << " " ); } I get the error(among others): error: boost/lambda/lambda.hpp: No such file or directory If I change the include path to: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> I get the error(among others): error: boost/lambda/core.hpp: No such file or directory But core.hpp is in the lambda directory: /usr/local/boost_1_34_1/boost/lambda$ ls algorithm.hpp control_structures.hpp lambda.hpp bind.hpp core.hpp loops.hpp casts.hpp detail numeric.hpp closures.hpp exceptions.hpp switch.hpp construct.hpp if.hpp I'm using the Xcode 2.4 IDE to run my C++ programs. I also tried to execute the program from the command line with the original include path: #include <boost/lambda/lambda.hpp> but I get the same error: ~/2testing/dir1$ g++ prog1.cpp prog1.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope I get the same errors again with the full include path: #include </user/local/boost_1_34_1/boost/lambda/lambda.hpp> $ g++ prog1.cpp In file included from prog1.cpp:1: /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:14:33: error: boost/lambda/core.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:21:52: error: boost/lambda/detail/operator_actions.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:22:61: error: boost/lambda/detail/operator_lambda_func_base.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:23:63: error: boost/lambda/detail/operator_return_type_traits.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:26:45: error: boost/lambda/detail/operators.hpp: No such file or directory /usr/local/boost_1_34_1/boost/lambda/lambda.hpp:30:46: error: boost/lambda/detail/member_ptr.hpp: No such file or directory prog1.cpp: In function 'int main()': prog1.cpp:8: error: 'boost' has not been declared prog1.cpp:8: error: expected namespace-name before ';' token prog1.cpp:8: error: '<type error>' is not a namespace prog1.cpp:11: error: '_1' was not declared in this scope What path should I be using? Or, should I set an environment variable somewhere?

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Geometry buffer algorithm: complete or not?
by John Lilley 22 Feb '13

22 Feb '13

I was looking here: http://www.boost.org/doc/libs/1_52_0/libs/geometry/doc/html/geometry/refere… And saw this: "The current implemetation only enlarges a box, which is not defined by OGC. A next version of the library will contain a more complete implementation" It looks like Boost::Geometry is incapable of buffering an arbitrary polygon. But various forum discussions refer to the buffer() algorithm like it actually works for the general case. Which is correct? John Lilley

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chaining functions input output
by MM 19 Feb '13

19 Feb '13

Hello, i have these 2 functions provided to me and I wonder whether they can somehow be chained without using intermediary memory? http://codepad.org/tTwkUQhp Rds, MM

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A cool book for c++11 is Published now (Revised Edition)
by Algocoders . 04 Feb '13

04 Feb '13

Hi All, Revised edition of the book : "Foundation of Algorithms in C++11, Volume 1(Revised Edition): Using and Extending C++11, Boost And Beyond" : is available now. @Amazon: http://www.amazon.com/Foundation-Algorithms-Volume-Revised-Edition/dp/14819… @Pothi.com (Indian Edition): http://pothi.com/pothi/book/chandra-shekhar-kumar-foundation-algorithms-c11… This book is vital to understand and extend the C++11 Algorithms by carefully worked out synthesis of language and library features with an eye at future evolution with special emphasis to : - Template Alias - constexpr - copy_backward - requires - std::enable_if : SFINAE - Private Cast - Type Functions - Type Traits - Explicit Template Instantiations and Specializations - Trailing Return Type - auto type specifier - Intermediate Traits Idiom - Value Type Deduction Framework Table of Contents : http://algocoders.com/sites/default/files/toc_foa_revised.pdf Sample Chapter : http://algocoders.com/sites/default/files/chapter1_foa_revised.pdf For more details, please visit the link : http://www.algocoders.com/article/books Have Fun ! Cheers, Algocoders http://www.algocoders.com

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[asio] How to handle 'Bad file descriptor'
by Torsten＠Robitzki.de 03 Feb '13

03 Feb '13

Hello, I have problems to understand, what might causing a 'Bad file descriptor' exception to be thrown in my application. The exception is most likely thrown by a call to tcp::socket::close. From the logs I have, I'm quit certain, that the last function calls on a socket are: s.shutdown(tcp::socket::shutdown_receive); s.shutdown(tcp::socket::shutdown_send); s.close(); // first time to cancel outstanding handlers s.close(); // a second time, later in the d'tor I'm not sure, whether it's the first or the second call to close(), that causes the exception. But what does 'Bad file descriptor' mean in this context? Is the underlying socket is somehow broken/corrupted? If so, there must be a bug in my code. If not, is it save to simply ignore the error? The program is not single threaded, but there is only one boost::io_service object which is run by a single dedicated thread. Kind reagards Torsten P.S: if someone interested in the code: https://github.com/TorstenRobitzki/Sioux/blob/master/source/server/connecti…; it's open source

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[Graph] visitor dijkstra_shortest_paths
by The Maschine 31 Jan '13

31 Jan '13

Hi all, Can someone explain me why I get an error with the first one and not the second? 1) (error) boost::dijkstra_shortest_paths(m_ugraph,*vertex_iterator_begin, boost::distance_map(boost::make_iterator_property_map(dist_map.begin(), boost::get(boost::vertex_index, m_ugraph))), boost::visitor(dijkstra_vis( *vertex_iterator_begin, superStorage ) )); 2) (good) boost::dijkstra_shortest_paths(m_ugraph,*vertex_iterator_begin, boost::distance_map(boost:: make_iterator_property_map(dist_map.begin(), boost::get(boost::vertex_index, m_ugraph))).visitor(dijkstra_vis( *vertex_iterator_begin, superStorage )) ); Why I need to "." the visitor on the distance_map? BFS is ok with it: (good) boost::breadth_first_search(m_ugraph, *vertex_iterator_begin , boost ::visitor(bfs_vis( *vertex_iterator_begin, superStorage ) )); Best, Tasos

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[Fusion] Why restrict 'copy' to equal sizes?
by TONGARI 31 Jan '13

31 Jan '13

Hi, As the counterpart of STL copy, I expected the src just need to be <= dst, but it requires equal sizes in Fusion. What's the rationale? Is it OK to loosen the restriction? (it just compiles if I change '==' to '<=') Thanks.

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