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Range_Ex and Multi-Index: conflicting mpl::begin and boost::begin
by Sandeep Gupta 18 Mar '09

18 Mar '09

Hi, I am under-impression that for_each construct of range_ex for all container concepts. However when I tried with multi-index it gave conflicting errors. Attached below is the code and corresponding errors. code: typedef multi_index_container< std::pair<value_type,int>, indexed_by< ordered_unique<member<pair<value_type,int>, value_type, &pair<value_type, int>::first> >, ordered_unique<member<pair<value_type,int>, int, &pair<value_type, int>::second> > > > mic; mic serialStore; for_each(serialStore, std::cout<<boost::lambda::_1<<' '); error: /home/sandeep/Computing/boost_1_38_0/boost/mpl/begin_end_fwd.hpp:22: error: ‘template<class Sequence> struct boost::mpl::begin’ is not a function, /home/sandeep/Computing/boost_1_38_0/boost/range/begin.hpp:96: error: conflict with ‘template<class T> typename boost::range_iterator::type boost::begin(T&)’ /home/sandeep/Computing/boost_1_38_0/boost/range_ex/./detail/adl_begin_end.hpp:27: error: in call to ‘begin’ /home/sandeep/Computing/boost_1_38_0/boost/mpl/begin_end_fwd.hpp:23: error: ‘template<class Sequence> struct boost::mpl::end’ is not a function, /home/sandeep/Computing/boost_1_38_0/boost/range/end.hpp:92: error: conflict with ‘template<class T> typename boost::range_iterator::type boost::end(T&)’ /home/sandeep/Computing/boost_1_38_0/boost/range_ex/./detail/adl_begin_end.hpp:35: error: in call to ‘end’ I apologies in advance if this is due to trivial omission. Thanks -sandeep

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[xpressive] is regex_match threadsafe?
by Sergey Skorokhodov 18 Mar '09

18 Mar '09

Hi, Is it safe to call regex_match with the same cregex|sregex object from different threads? Or should each thread use its own cregex|sregex object? TIA -- Sergey Skorokhodov

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[program options] allow unregistered options for config file
by Deane Yang 18 Mar '09

18 Mar '09

Instructions for how to allow unregistered options on the command-line are given here: http://www.boost.org/doc/libs/1_38_0/doc/html/program_options/howto.html#id… Is there any way to allow unregistered options for a configuration file, too?

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[boost-users][python]
by Germán Diago 18 Mar '09

18 Mar '09

Hello. I have a library which exposes the following function: namespace ftr { Player & getPlayer(int num); } and it's exposed to python by: def("getPlayer", &ftr::getPlayer, return_value_policy<reference_existing_object>()); This code used to work, but now I compile it and get this error when using it from the python module, under ubuntu 9.04: Traceback (most recent call last): File "/usr/lib/python2.5/site-packages/apport_python_hook.py", line 77, in apport_excepthook pr['PythonArgs'] = '%r' % sys.argv AttributeError: 'module' object has no attribute 'argv' Original exception was: Traceback (most recent call last): File "<string>", line 1, in <module> Boost.Python.ArgumentError: Python argument types in ftr.getPlayer(int) did not match C++ signature: getPlayer(int) Any help here, please? I don't know why this should happen.

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Re: [Boost-users] [graph] set of edges
by Michael Fawcett 18 Mar '09

18 Mar '09

On Mon, Mar 16, 2009 at 5:30 PM, Michael Fawcett <michael.fawcett(a)gmail.com> wrote: > On Mon, Mar 16, 2009 at 5:15 PM, Juan Antonio Farré Basurte > <jafb(a)tinet.org> wrote: > > Please try not to top post per guidelines. I've lost the attributions > unfortunately, but fixed the formatting a little. > >>> I meant for OutEdgeList, however I went back and tried vecS for >>> EdgeList as well and all my tests still passed and my program output >>> was still correct. Perhaps this was corrected in code but the docs >>> weren't updated? >> >> I don't think so... I'm working with version 1.38 and I had a std::map with >> edge_descriptor keys. >> I passed this map, wrapped as an associative_property_map, and added to a >> dynamic_properties object, to graph-reading functions. >> When I traversed the map contents to do something useful with it, looks like >> the descriptors where invalid. In some cases it just looked to do nothing. >> In other cases I got segmentation fault. When I changed to listS, everything >> worked all right. >> In the documentation it just says that it's "not guarranted" to work. And >> looks to be true. Works in some cases and not in others. > > It sounds like something assumes that those descriptors will not be > invalidated unless removed. Maybe Andrew can chime in? > > I would guess it's working for me by accident since I'm never removing > anything from the graphs I create. I'll make sure to keep my usage to > listS for now. Reposting with subject line changed. --Michael Fawcett

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factorial function
by agascon＠correo.ugr.es 18 Mar '09

18 Mar '09

Hi everyone, I'm new to boost (and not so new but not very experienced to c++) and I'm having problems with functions defined with a template, as factorial (http://www.boost.org/doc/libs/1_38_0/libs/math/doc/sf_and_dist/html/math_to…) My questions is, how do I call the funtion factorial? Why isn't it enough calling factorial(n) where n is an unsigned integer? Does one need to define the function specifying the result type before? If so, how? Thanks in advance. Greetings, Alberto.

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How to post a work into a io_service and wait for it run complete?
by �]邓 18 Mar '09

18 Mar '09

I created a io_service in main thread, for dispatch user request. And i created another io_service in a thread_pool, run some sync work(like database query). After main thread got some user request, it post a query into the io_service running in the thread_pool. After the query has been completed, query thread post a work to the main thread. But the next query cannot be handled until the last result was closed. So query thread need to wait main thread until it'll not using the result any more. How to do it? Now I write some code with mutex and condition_variables. but is there any better choice with out such things?

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correct usage of bind
by Sandeep Gupta 18 Mar '09

18 Mar '09

Hi, Both the statements below bind function buildPair. While the first works the other fails. What could be a possible fix. Thanks in advance. //---- Function to be used by bind ------------------------- template<typename X, typename Y> std::pair<X, Y> buildPair(X x, Y y) { std::pair<X,Y> apair(x,y); return apair; } (std::cout<<buildPair(_1,_2).first<<' ')(1,2); ///--compiles fine--------- (bind(buildPair,_1,_2))(3,5); ///-fails------------ Thanks sandeep

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correct usage of bind (pls ignore last email)
by Sandeep Gupta 18 Mar '09

18 Mar '09

Hi, The code below tries to chain function ft1 (argument is a pair) with function buildPair (returns a pair). template<typename X, typename Y> std::pair<X, Y> buildPair(X x, Y y) { std::pair<X,Y> apair(x,y); return apair; } int main() { typedef boost::function<void (std::pair<int,int>)> FuncType1_t; std::vector<std::pair<int,int> > myvec; FuncType1_t ft1 = bind(&std::vector<std::pair<int,int> > ::push_back, &myvec, _1); typedef boost::function<void(std::pair<int,int>)> FuncType2_t; FuncType2_t ft2 = bind(ft1, bind(buildPair<int,int>,_1,_2)); //compile fails return 0; } This fails. The problem however vanished if I replace the declaration "FuncType3 ft2..." with bind(ft1, bind(buildPair<int,int>,_1,_2))(3,5); So my question is what is correct type of bind(ft1, bind(buildPair<int,int>,_1,_2)); Thanks sandeep

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[parameter] type of function arguments
by Rutger ter Borg 17 Mar '09

17 Mar '09

I'm looking into the possibilities of using Boost.Parameter to introduce extra user-friendliness to a part of the numeric-bindings libraries (in this particular case, bindings for BLAS and LAPACK). Boost.Parameter looks like it is exactly what I need, making it easy to write functions with a couple of required, and many optional parameters. What I couldn't immediately catch from the documentation, is what the types of the passed arguments are of a BOOST_PARAMETER_FUNCTION. E.g., the example in section 2.1.4 says BOOST_PARAMETER_FUNCTION( [snip] ) { // ... body of function goes here... // use graph, visitor, index_map, and color_map } but it is not clear to me is how to easily get to the type of graph, visitor, etc., in the body of the function. Thanks in advance, Kind regards, Rutger ter Borg

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