October 2009 - Boost-users - lists.preview.boost.org

boost_python-vc90-mt-gd-1.39.dll not found?
by Tanja Zarić 19 Oct '09

19 Oct '09

Hello, I am new to Boost. Python. I am trying to integrate Python with C++ by using Boost Python library. I have used Boost 1.39.0, Boost Jam 3.1.17 and Python 2.5.4. I have problem running example so I would be grateful if someone helps me to solve it. I have built Boost Build with Bjam, using msvc ang gcc tool sets, according to this link: http://www.boost.org/doc/libs/1_40_0/libs/python/doc/building.html with C:\boost_1_39_0\…\quickstart> bjam toolset=msvc --verbose-test test and similar later C:\boost_1_34_0\…\quickstart> bjam toolset=gcc --verbose-test test It have passed the test. I have navigated to C:\boost\boost_1_39_0\libs\python\example\quickstart\bin\msvc-9.0\debug\threading-multi or similar C:\boost\boost_1_39_0\libs\python\example\quickstart\bin\gcc-mingw-3.4.5\debug, started python and tried to import extending module, but I got following error: " This application has failde to start because boost_python-vc90-mt-gd-1.39.dll was not found. Re-installing the application may fix the problem." or similar error message for gcc... I tried to solve by solution : http://selcuk-ozturk.com/post/2009/09/15/C2b2b-and-Python-with-BoostPython-… Still there is same error message. Anyone have idea? -- Tanja Zaric

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[interprocess] Is there a bug in spinlock atomic implementations 1.39 and 1.40?
by Sakharuk, Vladimir 19 Oct '09

19 Oct '09

Hi all > In both: > > boost/detail/spinlock_sync.hpp > boost/detail/smart_ptr/spinlock_sync.hpp > > > Spinlock does not has constructor, so it is possible to have > spinlock::v_ uninitialized and not to equal zero. > That means it may be locked by default and call below will always > return false... > bool try_lock() > { > int r = __sync_lock_test_and_set( &v_, 1 ); > return r == 0; > } > Am I missing something? > > Adding > Spinlock(): v_(0) {} > Looks like solves my issue. > g++ 4.1.2 on suse 2.6.16.46 > > Regards Vlad. > =============================================================================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html ===============================================================================

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DAG Graph Search
by Dan Bailey 19 Oct '09

19 Oct '09

Hi, I'm looking to do a downstream search over a DAG graph where I never advance past a node until all of the nodes linking to it have been seen. Clearly a breadth first search won't work, but using a topological sort, I can get a list of all the nodes in the correct order. However I only wish to search over the nodes downstream from any particular node (until I reach the leaf nodes), which doesn't work as this is the entire network even if it contains various sub-graphs. Is there a better algorithm or approach I can use to do this? Here's a simple example: a -> b b -> c c -> d a -> c I wouldn't ever want to look at c before b, but if I started at b for example, I would only want to see downstream of this. Any help would be appreciated, Cheers, Dan

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multi_index_comtainer questions
by Vladimir Voronkov 19 Oct '09

19 Oct '09

Hi, All, I just have started using boost and have some questions, answers on that i couldn’t find in the documentation. My interest is in using multi_index_container as combination of advantages of standard bidirectional list as well as fast lookup (insertion) of standard associative container (particularly set). Let’s say we have the following definitions: typedef boost::multi_index_container< UserInfo, boost::multi_index::indexed_by< boost::multi_index::sequenced<>, boost::multi_index::ordered_unique< boost::multi_index::identity<UserInfo>, UserInfoLess> > > UsersContainer; typedef UsersContainer::nth_index<0>::type UsersList; typedef UsersContainer::nth_index<1>::type UsersSet; Now we want to insert some value into this container the following way: UsersSet& setIndex = m_Users.get<1>(); std::pair<UsersSet::iterator, bool> insRet = setIndex.insert(someVal); The question is how can i acquire iterator of m_Users having the iterator UsersSet::iterator ? Do iterators keep the property of set’s iterators that they remain valid after insertion of an element? Thanks for the answers, Vladimir Voronkov.

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[boost::tokenizer] scope error usage of object run under win32 CL, ICL but fails under linux32 gcc
by Patryk Bukowinski 19 Oct '09

19 Oct '09

Hi all, I've some weird problem, its probably simple thing, but I'm probably to tired to find it out. g++ throws me following error : *getFunc.h: In static member function ‘static void Logic::setFunctionNameFromStringMsg(const char*, char*, unsigned int, unsigned int)’:* *getFunc.h:86: error: ‘tok’ was not declared in this scope * Code looks like this: *static void setFunctionNameFromStringMsg(const char *fTab, char *dst, unsigned int msg_size, unsigned int buf_size)** ** {** ** std::string msg_copy(fTab,msg_size);** **boost::char_separator<char> sep("[]@\n\r\t "); ** ** boost::tokenizer<boost::char_separator<char>> tok(msg_copy, sep);** ** std::string resFunc;** ** ....* * ....* *//line 86** ** if(tok.begin() != tok.end()) // check is there any function** ** {** ** resFunc=*(tok.begin());** **......* Funny thing is that there are no problems during CL and intel compilers win32 processing. Thanks for any advice. * * * *

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[iostreams] Can you flush yourself from within a stream?
by Adam Nielsen 19 Oct '09

19 Oct '09

Hi all, I have a class used as a Boost iostream: boost::iostreams::stream<my_stream> ms; The my_stream class implements a couple of extra methods (one example being to insert a block of data in the middle of the stream) however the stream does not get flushed before the call to these extra functions, which results in corrupted data: ms.write("1234", 4); ms.seekp(-2, std::ios::cur); ms->insert(2); // my_stream method This should result in "12__34", but unfortunately because of buffering, the insert() ends up happening before the write(), leaving you with just "1234". The problem is solved by flushing the cache all over the place: ms.write("1234", 4); ms.flush(); ms.seekp(-2, std::ios::cur); ms->insert(2); ms.flush(); However this isn't really ideal. I would rather the insert() function was able to flush itself before manipulating the underlying stream. Is this possible? Or am I going about this in entirely the wrong way?? ;-) Many thanks, Adam. -- class my_stream { public: typedef char char_type; typedef io::seekable_device_tag category; ...

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[graph][test][assign] warning in boost graph
by Andrey Torba 19 Oct '09

19 Oct '09

Hello All! In my unit tests i use Graph, Test and Assign libraries (boost 1.39, MSVC 2005). This is an example to reproduce warning: #include <boost/graph/topological_sort.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/assign.hpp> #include <vector> //#include <boost/test/unit_test.hpp> int main() { typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::bidirectionalS> G; typedef boost::graph_traits<G>::vertex_descriptor V; typedef std::map<V, boost::default_color_type> Map; G g; std::vector<V> sorted; Map m; boost::add_vertex(g); boost::topological_sort(g, std::back_inserter(sorted), color_map(boost::make_assoc_property_map(m))); //boost::assign::list_of<V>(0); return 0; } I noticed that when i uncomment both `#include <boost/test/unit_test.hpp>` and `boost::assign::list_of<V>(0);` the warning occur: boost\graph\depth_first_search.hpp(200) : warning C4267: 'argument' : conversion from 'size_t' to 'unsigned int', possible loss of data if one of the string is absent there is no warning. Any thoughts? -- Regards, Andrey

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Problem with binary serialization using std::wstring
by Macumber, Daniel 19 Oct '09

19 Oct '09

My project is using std::wstring extensively and I have been able to get both the text and xml serialization archives to work with it. However, I am getting a stream_error when trying to deserialize objects written to a binary archive. I think the serialization may be missing some objects. I have tracked the problem down to serializing a std::map<std::wstring, shared_ptr<IddKey>, iStringCompare> where IddKey is a class that supports serialization and iStringCompare is: struct iStringCompare{ bool operator()(const std::wstring& x, const std::wstring& y) const{ return boost::lexicographical_compare(x, y, boost::is_iless()); }; }; I have tried to replicate this problem in a simple test case to submit but have not been able to reproduce it outside of my real code. Here is the code that serializes to a binary archive: boost::filesystem::wpath path = iddPath; path.replace_extension(L"idd.bin"); { boost::filesystem::ofstream ofs(path); boost::archive::binary_oarchive out(ofs); out << iddFilePtr; } IddFilePtr newIddFilePtr; { boost::filesystem::ifstream ifs(path); boost::archive::binary_iarchive in(ifs); in >> newIddFilePtr; } I am not using binary_woarchive or binary_wiarchive because they don't compile with shared_ptr serialization and I have seen that you are not really supposed to use them. I am using the wstring versions of the text and xml archives that are working. Does anyone have any suggestions on how to track down my problem? Dan

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Problem with binary serialization using std::wstring
by Macumber, Daniel 19 Oct '09

19 Oct '09

Just as the docs said, using ios::binary when opening the file worked. Thanks, Dan

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[BGL] Using custom planar embedding
by Vicente Helano 18 Oct '09

18 Oct '09

Dears, I would like to use a custom embedding for a planar graph in order to pass it to the planar_face_traversal algorithm, but I couldn't get my code compiled yet (see the attachments). Could someone help me, please? Best regards, Vicente.

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