January 2009 - Boost-users - lists.boost.org

date-time library and checked iterators 2
by gast128 01 Feb '09

01 Feb '09

Dear all, I post half year ago about a problem in the Boost.DateTime library but never got an answer. So I try again: 'the date_facet::do_put_tm' fct. contains an illegal dereferncing in '&*a_format.begin()'. If the a_format string is empty VS2008 complains (and terminates) about illegal iterator dereference. I suspect though that VS2008 is right. Is it possible that this gets attention, or is something else wrong? Wkr, me

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Cosmetic warning in gcc 4.3
by Joel Falcou 01 Feb '09

01 Feb '09

I foudn that the following lines int he following files generates a huge amount of spurious warning in gcc 4.3 with -Wall : /boost/math/special_functions/gamma.hpp line 1264: tgamma1pm1(T z, const Policy& /* pol */) /boost/function_types/detail/pp_retag_default_cc/preprocessed.hpp line 18 BOOST_STATIC_CONSTANT(bits_t, value = ( (::boost::function_types::detail::bits<Tag> ::value & 0x00008000 ) |( ::boost::function_types::detail::bits<RefTag> ::value & 802) )); /boost/function_types/detail/pp_tags/preprocessed.hpp line 56 BOOST_STATIC_CONSTANT(bits_t, combined_bits = (LHS_bits & ~RHS_mask) | RHS_bits ); The later was signaled as a ticket in trac but I wanted to know if it was fixed/merged in the upcoming 1.38. -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35

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Do "entire range" standard algorithms already exist
by Kirk Korver 01 Feb '09

01 Feb '09

Group, I recently found the boost::range library. It seems very useful. An annoyance that I have with STL algorithms is that they are very verbose. Most of the time I need to do something over the entire range. I'm sure I'm not alone here. At any rate, I can easily do this: template< typename Range, typename Pred > inline typename boost::range_iterator<Range>::type find_if( Range& c, Pred pred ) { return std::find_if( boost::begin( c ), boost::end( c ), pred ); } Which then allows me to do this: void foo() { typedef std::vector <int> V_INT; V_INT v; v.push_back(1); v.push_back(2); v.push_back(3); V_INT::iterator it = find_if(v, std::bind2nd(std::equal_to<int>(), 2)); } Perfect. Exactly what I want. Search the entire vector, and I give it a predicate. I could easily create these functions for copy_if, erase_if, find_if, and for_each. My question: Do I need to go ahead and create the tiny wrapper functions, or do they already exist somewhere in Boost? If they exist already, I prefer to use those. Thank you in advance, Kirk

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[traits] Type of class of member function pointer
by Rutger ter Borg 01 Feb '09

01 Feb '09

Dear all, perhaps more out of exercise, but does any of you know whether it is possible to get to the type of the class of a member function pointer? I.e., to somehow get to type T in "R (T::*)()"? (in this particular case, a member function without arguments in class T returning R)? Thanks a lot, Rutger

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[Interprocess] Unable to list created shared memory via ipcs command
by Leo Giannelli 31 Jan '09

31 Jan '09

Hello, I am a new user of the Boost Libraries. Currently, I tried the Boost.Interprocess source library with an example program which creates a shared memory segment and writes a vector into the shared memory. A receiver process attaches to the named shared memory segment and outputs the vector. This all works has advertized. The one issue is that whenever I try to list the shared memory segment via the ipcs -m command I do not see the shared memory created from the sender program. This is the code snippet which creates the shared memory: #include <boost/interprocess/managed_shared_memory.hpp> ...managed_shared_memory segment (create_only ,"MySharedMemory" //segment name ,65536); //segment size in bytes ... Note: The sender program is running for 5 minutes before terminating and removing the shared memory. The binaries were built with g++ version 3.4.6 20060404 (Red Hat 3.4.6-8) RedHat Linux 5: Kernal Version : uname -a Linux xxx 2.6.9-67.ELsmp #1 SMP Wed Nov 7 13:56:44 EST 2007 x86_64 x86_64 x86_64 GNU/Linux Best Regards, Leo -- Be Yourself @ mail.com! Choose From 200+ Email Addresses Get a Free Account at www.mail.com

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[spirit2] where are the docs?
by Michael Marcin 31 Jan '09

31 Jan '09

I can't seem to find the spirit 2 documentation. Is there a copy online? -- Michael Marcin

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Tree library?
by Germán Diago 31 Jan '09

31 Jan '09

Is there any library in preparation in boost to use tree data structures? If not, I would like to know where I can find a good implementation of any open source tree library. I found this one, but I'm not sure if it's good quality. It seems to be: http://www.aei.mpg.de/~peekas/tree/ Thanks for your time.

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[gil] bad_cast exception
by Olivier Tournaire 30 Jan '09

30 Jan '09

Hi all, I am trying to use GIL and face a problem. Here is the code : namespace boost { namespace gil { /// Extension a GIL pour gerer les pixels "double" ... typedef pixel< double, boost::gil::gray_layout_t > gray64_pixel_t; typedef image< gray64_pixel_t, false > gray64_image_t; typedef image< gray64_pixel_t, true > gray64_planar_image_t; //typedef image_view< gray64_pixel_t > gray64_view_t; } } int main ( int argc , char **argv) { typedef boost::mpl::vector< boost::gil::gray8_image_t, boost::gil::gray16_image_t, boost::gil::gray32_image_t, //boost::gil::gray64_image_t, boost::gil::rgb8_image_t, boost::gil::rgb16_image_t, boost::gil::rgb32_image_t > my_img_types; typedef boost::mpl::vector< boost::gil::gray8_view_t, boost::gil::gray16_view_t, boost::gil::gray32_view_t, //boost::gil::gray64_view_t, boost::gil::rgb8_view_t, boost::gil::rgb16_view_t, boost::gil::rgb32_view_t > my_view_types; if ( argc < 4 ) { usage(); return 1; } std::string input_filename( argv[1] ); std::string output_filename( argv[3] ); int channel_index; try { channel_index = boost::lexical_cast<int>( argv[2] ); } catch( boost::bad_lexical_cast &e) { std::cout << "bad_lexical_cast exception : " << e.what() << std::endl; return 1; } boost::gil::any_image<my_img_types> runtime_image; boost::gil::any_image_view<my_view_types> runtime_view; try { boost::gil::jpeg_read_image( input_filename , runtime_image ); runtime_view = boost::gil::nth_channel_view( const_view(runtime_image) , channel_index ); boost::gil::jpeg_write_view( output_filename , runtime_view ); } catch( std::exception &e ) { std::cout << e.what() << std::endl; return 1; } return 0; } I get an exception on this line : runtime_view = boost::gil::nth_channel_view( const_view(runtime_image) , channel_index ); However, when I write : boost::gil::jpeg_write_view( output_filename , boost::gil::nth_channel_view( const_view(runtime_image) , channel_index ) ); everything goes well. Where is my mistake ? Best regards, Olivier -- Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France tel: (+33) 1 43 98 80 00 - 71 25 fax: (+33) 1 43 98 85 81

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Thread status
by Jens Luedicke 30 Jan '09

30 Jan '09

Hallo, how can I check if a given thread is runinng/finished/sleeping? Jens

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Re: [Boost-users] RBGL use with BGL minCut() function
by Gianni Loiacono 30 Jan '09

30 Jan '09

Hi Mr. Sutton thanks for the answer. I didn't know what was **R :-D**. Now I have readed some links and I have understand that RBGL is not adapt for my project (into the file zip Win Binary I have seen a .dll file than I thought that I could use more libraries :)). My goal is to do multi minimum cuts (gomory hu tree algorithm: http://www.corelab.ntua.gr/~syrganis/sources/Gomory-Hu.pdf ). The min-cut BGL functions give out only the min-cut value, I want to know what edges were cut. Can you help me? Sorry for my english ;/ Thanks a lot for your time and for the help. Bye.

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