November 2012 - Boost-users

[Program_options] Positional options are not parsed, "unrecognised option". A bug?
by Dmitry Shintyakov 04 Nov '12

04 Nov '12

Hello, everybody. I am having problems using Boost::Program_options library. I have a program, that have several optional keyword arguments, and 3 positional arguments. Keyword arguments are parsed well, but positional arguments are always causing an exception? saying: "unrecognised option" After spending 2 hours trying to find a problem, I decided to ask for help. I am using Boost 1.50.0-2, GCC 4.7.2 under Arch linux (32 bit). My example is almost exact copy from the tutorial, so I suspect that there is some bug. Example code (with all non-relevant code removed) follows. To test it, run it as following: ./a.out 123 123 test Expected behaviour is to see a line: Arguments: output=output.png width=123 height=123 Instead, I see this: terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail:: error_info_injector<boost::program_options::unknown_option> >' what(): unrecognised option '1' ==Test code== #include <iostream> #include <boost/program_options.hpp> using namespace std; int main( int argc, char * argv[] ) { namespace po = boost::program_options; string output_file; po::options_description desc("converter [options] width height source"); desc.add_options() ("help", "Show help message") ("output,o", po::value<string>( &output_file )->default_value("output.png"), "Output file to put converted image data to. Default is output.png") ; po::positional_options_description pos_desc; pos_desc.add("width",1).add("height",1).add("input-file",1); po::variables_map vm; po::store( po::command_line_parser(argc, argv) .options(desc) .positional(pos_desc) .run() , vm ); po::notify( vm ); if( vm.count("help") ){ cout << desc <<endl; return 0; } if (!vm.count("width") || !vm.count("height") || !vm.count("input-file") ){ cerr<<"Error: width, weight and input file must be specified"<<endl; return 1; } cout << "Arguments: output="<<output_file << " width="<<vm["width"].as<string>() << " height="<<vm["height"].as<string>()<<endl; return 0; }

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MingW compilation errors
by Alice Gamewell 04 Nov '12

04 Nov '12

I have managed to build the boost libraries with b2 and the gcc toolset option. Alas, whenever I use a header which invokes such a library in Code::Blocks chained with MingW I get these errors: undefined reference to _Unwind_SiLj_Register undefined reference to _Unwind_SiLj_Unregister undefined reference to _Unwind_SiLj_Resume undefined reference to __gxx_personality_sj0 undefined reference to _WSACleanup@0 undefined reference to _WSAStartup@8 All but the last two repeatedly. I would really appreciate anyone who could point me out of this mess. Thanks!

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[Date Time] MSVC CRT assertion stops execution in debug mode
by Fumito Hamamura 03 Nov '12

03 Nov '12

Hi, I'm testing the code below using boost 1.50.0 and Visual C++ 2008. What I expected was, the ptime t doesn't throw an exception even though it doesn't get a valid date time string passed by the wstringstream ss. When it is compiled in Release mode, it works as expected, i.e. the program runs without an error, but when compiled in Debug mode, the program stops because debug assertion fails in _chvalidator in isctype.c, which is called by std::isspace. Is there a known workaround for this? Thanks, Fumito ----- #include <iostream> #include <string> #include "boost/date_time/posix_time/posix_time.hpp" int wmain(int argc, wchar_t* argv[]) { boost::posix_time::wtime_input_facet* dt_facet(new boost::posix_time::wtime_input_facet(L"%Y/%m/%d %H:%M")); std::wstringstream ss; boost::posix_time::ptime t; ss.imbue(std::locale(ss.getloc(), dt_facet)); ss << L"あいうえお"; ss >> t; return 0; } -----

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C++ announcements coming tomorrow
by Beman Dawes 03 Nov '12

03 Nov '12

Herb Sutter, the Convenor of the ISO C++ Standards Committee, will be making some announcements tomorrow likely to be of interest to C++ developers in general and Boosters in particular. The venue is a talk titled "The Future of C++" at the Microsoft Build Conference. While some of Herb's announcements will be specific to Microsoft, the key C++ initiatives involve Boost and the whole C++ community. Some of the ideas evolved from feedback Herb got at C++Now/BoostCon 2012 last May. I'll post a summary of the announcements tomorrow, but you can also watch the live stream at http://channel9.msdn.com at 12:45 PM Pacific time. For other time zones, see http://www.timeanddate.com/worldclock/fixedtime.html?iso=20121102T1945 --Beman PS: We don't usually post teasers like this on the Boost lists, but Herb asked that a notice be posted, and given the endless work he has put in on this over the summer, I couldn't say no.

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boost with mingw
by Kraus Philipp 03 Nov '12

03 Nov '12

Hello, I try to build Boost with MinGW / MSYS. I have found in the dokumentation http://www.boost.org/doc/libs/1_51_0/more/getting_started/windows.html that MinGW shell is not supported, but I can build bJam with booststrap.sh --toolset=mingw under the shell, but I get the error: mingw.jam: No such file or directory Can I build boost under MinGW shell or another shell with the MinGW gcc? Thanks Phil

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[Filesystem] Reverse traversal of boost::filesystem::path::const_iterator?
by Nat Linden 02 Nov '12

02 Nov '12

I've stumbled across some code in our code base that wants to walk up a fixed number of containing parent directories from the starting path. (It's in a Mac application bundle nested within another.) boost::filesystem::path::[const_]iterator is described as bidirectional. But boost::filesystem::path has no rbegin() or rend(). In libs/filesystem/test/path_test.cpp's iterator_tests(), I see, for a path variable named itr_ck, use of boost::prior(itr_ck.end()). That suggests that usage of this form would be legal: path mypath = /* ...something... */; for (path::const_iterator rcomp(mypath.end()), rend(mypath.begin()); rcomp != rend; --rcomp) { // ... use boost::prior(rcomp) ... } Am I correct? Given the way some containers implement end(), I always feel nervous about decrementing end(). I'm happy to see that Boost.Filesystem's own tests guarantee that usage; but is there anything in the documentation that would have assured me of that?

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boost::heap::skew_heap(1_51_0) ordered_iterator
by imns70 02 Nov '12

02 Nov '12

Hi This question pertains to boost::heap::skew_heap as defined here:- http://www.boost.org/doc/libs/1_51_0/doc/html/boost/heap/skew_heap.html Can you please help me understand what is the complexity of skew heap traversal using ordered_iterator. I am traversing over the heap, using ordered_iterator as shown in code below :- for(bk_heap::ordered_iterator it=buy_heap->ordered_begin();it!=buy_heap->ordered_end();it++) { /// some code here... } I suspect it to be O(n), but just want to make sure. Thanks in advance. -- View this message in context: http://boost.2283326.n4.nabble.com/boost-heap-skew-heap-1-51-0-ordered-iter… Sent from the Boost - Users mailing list archive at Nabble.com.

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advice with containers and data types
by Georg.Kellerer＠lfu.bayern.de 02 Nov '12

02 Nov '12

Hi all, i am a newbie to boost and hope, somebody here can give me an advice. i want to change the implementation of an existing container class in one of my projects. It is a container which for the moment is based on a very old roguewave version which should be replaced by boost. main features of this container are: - the container is based on a hashmap. - the key datatype can be string or int. - the value data type can be string, int, double, time, date, the container type itself and another container type. I thought about implementing the class based on a map container with boost:any as key and value type. is this possible? Or do you have other and even better recommendations for me? i am a bit confused about the great number of diferent containers and datastructures the boost library offers. Thanks in advance, Georg

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[phoenix] Using with Boost.Function.
by Robert Jones 02 Nov '12

02 Nov '12

Can anyone tell me the correct incantation to get the 'Not OK' lines to work? Thx, Rob. #include <boost/function.hpp> #include <boost/phoenix/core.hpp> #include <boost/phoenix/operator.hpp> #include <boost/phoenix/bind/bind_member_variable.hpp> #include <boost/phoenix/bind/bind_function.hpp> #include <boost/function.hpp> #include <list> struct S { int i; }; void f( std::list<S> & l, int i ) { using boost::phoenix::arg_names::_1; using boost::phoenix::arg_names::_2; // OK l.remove_if( bind( & S::i, _1 ) >= i ); *// Not OK.* * boost::function<bool( int, int )> pred = _1 >= _2;* * l.remove_if( bind( pred, _1, i ) );* }

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Iterator Range, sub range of a desired size
by David Kimmel 02 Nov '12

02 Nov '12

Is there a function in BOOST, given a starting point and a desired size, that returns iterators for a (sub) range? For example, given: a boost::circular_buffer which contains: 1 2 3 4 5 6 7 8 9 10 a starting point which is an iterator pointing to 5 and finally a desired size which is an int s = 4 The result of which would be iterators producing: 5 6 7 8 A possible implementation might be this (but I was hoping there was a BOOST version since I can't find an STD algorithm) template <typename Itr> std::pair<Itr, Itr> getWindowDown(Itr begin, Itr end, Itr start, const int windowSize) { // Down first, then up if need be const Itr bottom = (end - start > windowSize) ? (start + windowSize) : (end); const Itr top = (bottom - begin > windowSize) ? (bottom - windowSize) : (begin); return make_pair(top, bottom); } Thanks, -- View this message in context: http://boost.2283326.n4.nabble.com/Iterator-Range-sub-range-of-a-desired-si… Sent from the Boost - Users mailing list archive at Nabble.com.

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