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mpl::switch question
by Istvan Buki 18 Aug '04

18 Aug '04

Hello, I've just tried to compile a small piece of code using mpl::switch_ starting from an example Aleksey Gurtovoy sent to this list a while ago. I slightly modified the code to use the boost::is_same<T,U> template but I can't make it compile. On the other hand, if I comment out the line in the switch_body containing the is_same template, it compile without any problem. I spent the whole day on this and I'm lost. Any help would be welcome. Thanks, Istvan PS: I'm using boost 1.30.2 and g++ 3.3.3. #include "boost/mpl/vector.hpp" #include "boost/mpl/switch.hpp" #include "boost/mpl/project1st.hpp" #include "boost/mpl/pair.hpp" #include "boost/mpl/always.hpp" #include "boost/mpl/bool.hpp" #include "boost/mpl/assert_is_same.hpp" #include "boost/type_traits/remove_reference.hpp" #include "boost/type_traits/add_const.hpp" #include "boost/type_traits/is_pointer.hpp" #include "boost/type_traits/is_reference.hpp" #include "boost/type_traits/is_same.hpp" using namespace boost::mpl ; using boost::mpl::_ ; struct MyType { typedef int type ; } ; int main() { typedef vector< pair< boost::is_pointer<_1>, _1 > // If the following line is commented out it compile. , pair< boost::is_same<_1, _1 >, boost::add_const<_1> > , pair< boost::is_reference<_1>, boost::remove_reference<_1> > , pair< always<bool_<true > >, boost::add_const<_1> > > switch_body; typedef switch_< switch_body, char& >::type t1; typedef switch_< switch_body, int* >::type t2; typedef switch_< switch_body, int >::type t3; BOOST_MPL_ASSERT_IS_SAME(t1, char); BOOST_MPL_ASSERT_IS_SAME(t2, int*); BOOST_MPL_ASSERT_IS_SAME(t3, int const); }

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RE: [Boost-users] regex: match_results::const_reference is someti messub_match<Bidi Iterator>, sometimes const char?
by Richard Reitmeyer 17 Aug '04

17 Aug '04

Thanks for your help. (And all the effort that went into the regex library.) I'm using 1.31.0 (unpatched). After a more careful examination, my problem was that I was passing the wrong kind of allocator as a template parameter. Richard > -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org] On Behalf Of John Maddock > Sent: Tuesday, August 17, 2004 5:33 AM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] regex: > match_results::const_reference is sometimessub_match<Bidi > Iterator>, sometimes const char? > > > > The regex library is extremely helpful: thanks for all your efforts. > > > > I've got a problem with gcc and stlport and boost: when I try > > to get a submatch on other platforms, I can take my match object, m, > > and do things like > > > > m[n].str(); // works great elsewhere > > > > But with gcc / stlport, with BOOST_NO_STD_ALLOCATOR not defined, > > the const_reference type is defined as Allocator::const_reference > > (which is `const char'), rather than sub_match<BidiIterator>. > > So operator[] gives me a char, and life isn't so good. > > > > Any hints as to where I went astray? > > Works for me (with Boost-1.31.0 + latest patches), what > version are you > using? > > John. > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

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BGL-kamada_kawai_spring_layout
by Gordon Smith 17 Aug '04

17 Aug '04

Just playing with the kamada_kawai_spring_layout, so far for any non trivial graph (more then 4 nodes) - it seems to just go into an infinite loop. The graph is undirected but would contain "circular" paths - thoughts? Gordon.

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Additional information on linking problems
by Daniel Huber 17 Aug '04

17 Aug '04

Hi, I have done some additional testing on th eproblem that I reported yesterday, and I have found that the problem I was having with static linking under gcc 2.95.3 also occurs on gcc 3.2.2. I get basically the same error message (see below). I guess that the reason I get the message for the static linking but not for the dynamic linking might be that the undefined references in a shared library are ok as long as those functions are not called. Is that correct? I looked at the code, and as far as I can tell, the functions that the compiler is complaining about are in fact defined. Does anyone have any suggestions? Thanks, Daniel g++ -L $HOME/linux/lib/boost/lib -static -lboost_filesystem -gcc -I $HOME/linux/lib/boost/include/boost-1_31 test_boost.cxx /tmp/ccP4gcx3.o(.text+0x19): In function `main': : undefined reference to `boost::filesystem::initial_path()' /tmp/ccP4gcx3.o(.text+0x3e): In function `main': : undefined reference to `boost::filesystem::native(std::basic_string<char, std: :char_traits<char>, std::allocator<char> > const&)' /tmp/ccP4gcx3.o(.text+0x4f): In function `main': : undefined reference to `boost::filesystem::path::path[in-charge](char const*, bool (*)(std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&))' /tmp/ccP4gcx3.o(.text+0x5f): In function `main': : undefined reference to `boost::filesystem::system_complete(boost::filesystem:: path const&)' /tmp/ccP4gcx3.o(.text+0x114): In function `main': : undefined reference to `boost::filesystem::exists(boost::filesystem::path cons t&)' /tmp/ccP4gcx3.o(.text+0x137): In function `main': : undefined reference to `boost::filesystem::path::native_file_string() const' /tmp/ccP4gcx3.o(.text+0x1ba): In function `main': : undefined reference to `boost::filesystem::is_directory(boost::filesystem::pat h const&)' /tmp/ccP4gcx3.o(.text+0x1dd): In function `main': : undefined reference to `boost::filesystem::path::native_directory_string() con st' /tmp/ccP4gcx3.o(.text+0x28c): In function `main': : undefined reference to `boost::filesystem::is_directory(boost::filesystem::pat h const&)' /tmp/ccP4gcx3.o(.text+0x2c0): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccP4gcx3.o(.text+0x342): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccP4gcx3.o(.text+0x404): In function `main': : undefined reference to `boost::filesystem::path::leaf() const' /tmp/ccP4gcx3.o(.text+0x572): In function `main': : undefined reference to `boost::filesystem::path::native_file_string() const' /tmp/ccP4gcx3.o(.gnu.linkonce.t._ZN5boost10filesystem18directory_iteratorC1ERKNS 0_4pathE+0x1f): In function `boost::filesystem::directory_iterator::directory_it erator[in-charge](boost::filesystem::path const&)': : undefined reference to `boost::filesystem::detail::dir_itr_init(boost::shared_ ptr<boost::filesystem::detail::dir_itr_imp>&, boost::filesystem::path const&)' /tmp/ccP4gcx3.o(.gnu.linkonce.t._ZNK5boost10filesystem18directory_iterator11dere ferenceEv+0xd): In function `boost::filesystem::directory_iterator::dereference( ) const': : undefined reference to `boost::filesystem::detail::dir_itr_dereference(boost:: shared_ptr<boost::filesystem::detail::dir_itr_imp> const&)' /tmp/ccP4gcx3.o(.gnu.linkonce.t._ZN5boost10filesystem18directory_iterator9increm entEv+0xd): In function `boost::filesystem::directory_iterator::increment()': : undefined reference to `boost::filesystem::detail::dir_itr_increment(boost::sh ared_ptr<boost::filesystem::detail::dir_itr_imp>&)' collect2: ld returned 1 exit status

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regex: match_results::const_reference is sometimes sub_match<Bidi Iterator>, sometimes const char?
by Richard Reitmeyer 17 Aug '04

17 Aug '04

Hello, all. The regex library is extremely helpful: thanks for all your efforts. I've got a problem with gcc and stlport and boost: when I try to get a submatch on other platforms, I can take my match object, m, and do things like m[n].str(); // works great elsewhere But with gcc / stlport, with BOOST_NO_STD_ALLOCATOR not defined, the const_reference type is defined as Allocator::const_reference (which is `const char'), rather than sub_match<BidiIterator>. So operator[] gives me a char, and life isn't so good. Any hints as to where I went astray? Richard

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minimal use of strong_components
by Michael W Daniels 16 Aug '04

16 Aug '04

boost 1.31.0, msvc 7.1 I'm trying to understand how to use the BGL and the strong_components algorithm in particular. From the example in the documentation, it seems like this minimal file should compile: ==test.cpp== #include <boost/graph/adjacency_list.hpp> #include <boost/graph/strong_components.hpp> #include <string> using namespace std; using namespace boost; typedef adjacency_list<setS, setS, bidirectionalS, property<vertex_name_t, string> > Graph; int testcomps() { Graph gramgraph; vector<int> component(num_vertices(gramgraph)); return strong_components(gramgraph, &component[0]); } ==end== Instead, I get the error below. It seems as though it doesn't like the component map type, but I don't know what I should use instead. Any help anyone could provide would be appreciated. ==error== Compiling... test.cpp e:\boost-msvc\include\boost-1_31\boost\property_map.hpp(159) : error C2664: 'const T &get<std::allocator<_Ty>::value_type>(const T *,ptrdiff_t)' : cannot convert parameter 2 from 'Vertex ' to 'ptrdiff_t' with [ T=std::allocator<int>::value_type, _Ty=int ] This conversion requires a reinterpret_cast, a C-style cast or function-style cast e:\boost-msvc\include\boost-1_31\boost\property_map.hpp(156) : while compiling class-template member function 'void boost::ReadablePropertyMapConcept<PMap,Key>::constraints(void)' with [ PMap=int *__w64 , Key=Vertex ] e:\boost-msvc\include\boost-1_31\boost\concept_check.hpp(49) : see reference to class template instantiation 'boost::ReadablePropertyMapConcept<PMap,Key>' being compiled with [ PMap=int *__w64 , Key=Vertex ] e:\boost-msvc\include\boost-1_31\boost\property_map.hpp(215) : see reference to function template instantiation 'void boost::function_requires<boost::ReadablePropertyMapConcept<PMap,Key>>(boost::mpl::identity<T> *)' being compiled with [ PMap=int *__w64 , Key=Vertex , T=boost::ReadablePropertyMapConcept<int *__w64 ,Vertex > ] e:\boost-msvc\include\boost-1_31\boost\property_map.hpp(214) : while compiling class-template member function 'void boost::ReadWritePropertyMapConcept<PMap,Key>::constraints(void)' with [ PMap=int *__w64 , Key=Vertex ] e:\boost-msvc\include\boost-1_31\boost\concept_check.hpp(49) : see reference to class template instantiation 'boost::ReadWritePropertyMapConcept<PMap,Key>' being compiled with [ PMap=int *__w64 , Key=Vertex ] e:\boost-msvc\include\boost-1_31\boost\graph\strong_components.hpp(111) : see reference to function template instantiation 'void boost::function_requires<boost::ReadWritePropertyMapConcept<PMap,Key>>(boost::mpl::identity<T> *)' being compiled with [ PMap=int *__w64 , Key=Vertex, T=boost::ReadWritePropertyMapConcept<int *__w64 ,Vertex> ] e:\boost-msvc\include\boost-1_31\boost\graph\strong_components.hpp(166) : see reference to function template instantiation 'boost::property_traits<PA>::value_type boost::detail::strong_components_impl<Graph,ComponentMap,RootMap,boost::iterator_property_map<RandomAccessIterator,IndexMap,T,R>,int,int,boost::no_property>(const Graph &,ComponentMap,RootMap,DiscoverTime,const boost::bgl_named_params<int,Tag> &)' being compiled with [ PA=std::allocator<int>::value_type *__w64 , Graph=Graph, ComponentMap=std::allocator<int>::value_type *__w64 , RootMap=boost::iterator_property_map<std::vector<Vertex>::iterator,boost::detail::choose_pmap_helper<boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_index_t>::type,Graph,boost::vertex_index_t>::const_result_type,std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr RootMap=boost::iterator_property_map<std::vector<Vertex>::iterator,boost::detail::choose_pmap_helper<boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_index_t>::type,Graph,boost::vertex_index_t>::const_result_type,std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr >::value_type,std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr >::value_type & >, RandomAccessIterator=std::vector<size_type>::iterator, IndexMap=boost::detail::choose_pmap_helper<boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_index_t>::type,Graph,boost::vertex_index_t>::const_result_type, T=std::allocator<size_type>::value_type, R=std::allocator<size_type>::value_type &, DiscoverTime=boost::iterator_property_map<std::vector<size_type>::iterator,boost::detail::choose_pmap_helper<boost::property_value< boost::bgl_named_params<int,int>,boost::vertex_index_t>::type,Graph,boost::vertex_index_t>::const_result_type,std::allocator<size_type>::value_type,std::allocator<size_type>::value_type &>, Tag=int ] e:\boost-msvc\include\boost-1_31\boost\graph\strong_components.hpp(179) : see reference to function template instantiation 'boost::property_traits<PA>::value_type boost::detail::strong_comp_dispatch2<boost::detail::error_property_not_found>::apply<Graph,ComponentMap,RootMap,int,int,boost::no_property>(const Graph &,ComponentMap,RootMap,const boost::bgl_named_params<T,Tag> &,boost::detail::error_property_not_found)' being compiled with [ PA=std::allocator<int>::value_type *__w64 , Graph=Graph, ComponentMap=std::allocator<int>::value_type *__w64 , RootMap=boost::iterator_property_map<std::vector<Vertex>::iterator,boost::detail::choose_pmap_helper<boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_index_t>::type,Graph,boost::vertex_index_t>::const_result_type,std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr RootMap=boost::iterator_property_map<std::vector<Vertex>::iterator,boost::detail::choose_pmap_helper<boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_index_t>::type,Graph,boost::vertex_index_t>::const_result_type,std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr >::value_type,std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr >::value_type & >, T=int, Tag=int ] e:\boost-msvc\include\boost-1_31\boost\graph\strong_components.hpp(216) : see reference to function template instantiation 'boost::property_traits<PA>::value_type boost::detail::scc_helper2<Graph,ComponentMap,boost::iterator_property_map<RandomAccessIterator,IndexMap,T,R>,int,int,boost::no_property,boost::property_value<PropertyList,Tag>::type>(const Graph &,ComponentMap,RootMap,const boost::bgl_named_params<int,int> &,DiscoverTimeMap)' being compiled with [ PA=std::allocator<int>::value_type *__w64 , Graph=Graph, ComponentMap=std::allocator<int>::value_type *__w64 , RandomAccessIterator=std::vector<Vertex>::iterator, IndexMap=boost::detail::choose_pmap_helper<boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_index_t>::type,Graph,boost::vertex_index_t>::const_result_type, T=std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr T=std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr >::value_type, R=std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr R=std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr >::value_type & , PropertyList=boost::bgl_named_params<int,int>, Tag=boost::vertex_discover_time_t, RootMap=boost::iterator_property_map<std::vector<Vertex>::iterator,boost::detail::choose_pmap_helper<boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_index_t>::type,Graph,boost::vertex_index_t>::const_result_type,std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,b oost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr >::value_type,std::allocator<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>>,boost::setS,boost::setS,boost::bidirectionalS,boost::property<boost::vertex_name_t,std::string>,boost::no_property,boost::no_property,boost::listS>::config::vertex_ptr >::value_type & >, DiscoverTimeMap=boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_discover_time_t>::type ] e:\boost-msvc\include\boost-1_31\boost\graph\strong_components.hpp(229) : see reference to function template instantiation 'boost::property_traits<PA>::value_type boost::detail::strong_comp_dispatch1<boost::detail::error_property_not_found>::apply<Graph,ComponentMap,int,int,boost::no_property>(const Graph &,ComponentMap,const boost::bgl_named_params<T,Tag> &,boost::detail::error_property_not_found)' being compiled with [ PA=std::allocator<int>::value_type *__w64 , Graph=Graph, ComponentMap=std::allocator<int>::value_type *__w64 , T=int, Tag=int ] e:\boost-msvc\include\boost-1_31\boost\graph\strong_components.hpp(243) : see reference to function template instantiation 'boost::property_traits<PA>::value_type boost::detail::scc_helper1<Graph,ComponentMap,boost::property_value<PropertyList,Tag>::type,int,int,boost::no_property>(const Graph &,ComponentMap,const boost::bgl_named_params<T,int> &,RootMap)' being compiled with [ PA=std::allocator<int>::value_type *__w64 , Graph=Graph, ComponentMap=std::allocator<int>::value_type *__w64 , PropertyList=boost::bgl_named_params<int,int>, Tag=boost::vertex_root_t, T=int, RootMap=boost::property_value<boost::bgl_named_params<int,int>,boost::vertex_root_t>::type ] e:\boost-msvc\include\boost-1_31\boost\graph\strong_components.hpp(253) : see reference to function template instantiation 'boost::property_traits<PA>::value_type boost::strong_components<Graph,ComponentMap,int,int,boost::no_property>(const Graph &,ComponentMap,const boost::bgl_named_params<T,Tag> &)' being compiled with [ PA=std::allocator<int>::value_type *__w64 , Graph=Graph, ComponentMap=std::allocator<int>::value_type *__w64 , T=int, Tag=int ] e:\Projects\gidlp\parser\test.cpp(13) : see reference to function template instantiation 'boost::property_traits<PA>::value_type boost::strong_components<Graph,std::allocator<_Ty>::value_type*__w64 >(const Graph &,ComponentMap)' being compiled with [ PA=std::allocator<int>::value_type *__w64 , _Ty=int, Graph=Graph, ComponentMap=std::allocator<int>::value_type *__w64 ] ==end==

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RTTI for VC 6
by Samuel 16 Aug '04

16 Aug '04

VC 6 has an option for Run-Time Type Information (RTTI) that is normally off. I was able to compile and execute a sample program that had a problem. I noticed that Boost uses RTTI (such as the dynamic_cast operator), so I checked to see if the option was on; it was not. I turned the option on and the program worked. That problem is probably a known problem, but something such as the following can be added somewhere to not allow a VC 6 program to even compile if the RTTI option is off. I think it could make things a little easier for some beginners. # if !defined(_CPPRTTI) # error "Boost requires use of RTTI" # endif

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Re: [Boost-users] Re: RTTI for VC 6
by Samuel 16 Aug '04

16 Aug '04

[The message I am replying to was sent from a newsgroup and I am sending my reply (this) as a message to the list.] "Edward Diener" <eddielee(a)tropicsoft.com> wrote in message news:cfmhi0$4fd$1@sea.gmane.org... > > What Mr. Dimov is saying is that it is impossible to place the code you > would like to use above in Boost because it would affect other Boost > libraries which do not need RTTI to work. That's no problem. The Boost headers already have more than 400 (including comment) lines that test for the "BOOST_MSVC" preprocessor symbol. In other words, there is already an abundance of code that is relevant only to MS VC. > Furthermore if it were placed in > the header file of a library which did need RTTI to work, just including > that header file, without actually using code in it that needed RTTI such as > dynamic_cast, would cause an immediate compile time error. Perhaps. I hope, though, that the possibility that it might not be useful won't prevent someone from communicating the idea to someone familiar with the relevant headers, since there is a possibility that it might be useful. I have more confidence in the developers that a solution is possible. I might have missed something, but I don't understand why it is relevant to say that it won't work. It might not work, but it might work. Yet you are saying it definitely won't work. That seems innapropriate to me.

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RE: [Boost-users] RTTI for VC 6
by Bjorn.Karlsson＠readsoft.com 16 Aug '04

16 Aug '04

Enough of this. There will be no more insults, and no more blame, in this thread. Please try again, in a more productive manner. Thanks, Bjorn Karlsson Moderator [Everything snipped]

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Boost.Python 'Fatal Error'
by Ed Fear 16 Aug '04

16 Aug '04

Hello there, I've just started using Boost.Python, and find it absolutely invaluable. For the moment, my main task is embedding the python interpreter within an application of mine, and I have successfully built a small application that can load a module, execute a Python function and then collect the result. The next logical step was to extend the Python script somewhat into objects. I wrote some extra code in the script which I checked with the command line interpreter and verified to work. Before changing the C++ code to actually /use/ these new objects, I decided to just see what would happen if I kept exactly the same C++ code but with the new Python script (which still contains the function used for the last example). It ran fine - producing the correct output - but then exited abruptly with the following message: "Fatal Python error: PyThreadState_Get: no current thread". The changes to the original script file were the addition of two new classes - OptionsGUI and Button - and, oddly, commenting out Button makes the program work again (I say oddly because it's simply a class with a constructor, nothing more). Evidently I'm using the library incorrectly, and have searched through the documentation for things I might have done wrong but alas, I do find it rather daunting. I also noticed that my code is quite different from examples - is this a correct way to be doing things? And yes, at present, I'm not doing any exception or error handling - I'm a little unclear on it but I'm sure I will be able to do it given time :) For those wishing to look at the source, I have put the two files - EmbeddedPythonFunc.cpp and script2.py - in my webspace to prevent everyone having to download them as attachments. They are available at the following addresses: http://kutsurogu.pwp.blueyonder.co.uk/EmbeddedPythonFunc.cpp http://kutsurogu.pwp.blueyonder.co.uk/script2.py (incidentally, I didn't include stdafx.h because it simply includes iostream, tchar.h and boost/python.hpp). I hope I have sent my help request to the right place! Apologies if I have not. Thank you in advance, Ed Fear

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