March 2007 - Boost-users - lists.preview.boost.org

[BGL-Python] __len__ and __iter__ for property maps
by George Sakkis 21 May '07

21 May '07

I'm trying to build BGL-Python from SVN. I managed to build it successfully on Windows (VC 8.0) but I'm having problems with gcc 3.4 on Linux; although it does compile, it doesn't expose in Python two property map methods, __len__ and __iter__. I think I narrowed it down to the non-selection of a template specialization: // boost/graph/python/property_map.hpp namespace boost { namespace graph { namespace python { namespace detail { / * skip other stuff */ template<typename Class, typename T, typename IndexMap> void property_map_extras(Class& pm, type<vector_property_map<T, IndexMap> >) { pm.def("__len__", &py_vector_property_map_length<T, IndexMap>); typedef typename std::vector<T>::iterator value_iterator; simple_python_iterator<value_iterator>::declare("ValueIterator"); pm.def("__iter__", &py_vector_property_map_values<T, IndexMap>); } template<typename Class, typename PropertyMap> inline void property_map_extras(Class&, type<PropertyMap>) { } } // end namespace detail */ So for __len__ and __iter__ to be included, the first overloading of property_map_extras must be called. That's what happens with VC 8.0 (in fact I can remove the second empty function and compiles just fine), but gcc selects the second one. Can anyone help and/or reproduce it ? Thanks, George

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boost in a mixed CLR assemby
by Daniel J. Kelly 09 May '07

09 May '07

I realize it is not officially supported, but has anyone had success using boost libraries in a mixed CLR assembly? I am using visual studio 2005. I have been trying to accomplish this in an applicatation that has a Windows Forms front end, whose enire back end is build of libraries written in standard C++, making extensive use of boost, especially smart pointers and threads. The specific problem I am having involved initializing static variables. For instance, I have a global variable: boost::mutex osmutex; The program compiles and links fine, but during static initialization, I receive an error indicating _CrtIsValidHeapPointer(pUserData) is invalid. Looking at the stack unwind, the calling code is the "dynamic initializer for 'osmutex'". My suspicion is that the boost library is linking to a different run time library than my mixed code, and that the pointer being rejected is happening as a result of it coming from a different heap. I would like try to check this hypothesis by building boost forcing it to link to the correct C++ runtime library used by mixed assemblies (msvcmrtd.dll), but I am not familar enough with the boost build system to do this.

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read_graphviz question
by Jeffrey Holle 26 Apr '07

26 Apr '07

I'm using the post 1.31.1 version of boost, which has a much nicer read_graphviz function. I'm wondering if there is a way to "ignore" unwanted properties, something akin to sending them to /dev/null. My present experience is that if an unexpected property is found, an exception is thrown. Is there a way to express that a given property is to be ignored? Better yet, is there a way to say that all unexpected properties are to be ignored?

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[BGL] How to use an array in bundled property?
by Shufei Fan 16 Apr '07

16 Apr '07

I defined an double array inside bundled vertex property, and have trouble finding ways of accessing it. Neither can I find any where in the document an example on it. Your input will be much appreciated! my graph is defined as follows: struct Node { double mode[3]; // this is hard to access }; struct Edge { double nPixels; unsigned short nTh; //no problem access them }; typedef boost::adjacency_list< boost::vecS, boost::vecS, boost::bidirectionalS, Node, Edge> Graph; Graph colGraph; I have no problem with accessing the 'nPixels' in Edge property, boost::property_map<Graph, double Edge::*>::type ew = get(&Edge::nPixels, *colGraph);//edge weight But I am in a great deal of trouble finding ways of accessing 'mode' in Node property. compiler error here: boost::property_map<Graph, double Node::*>::type nm = get(&Node::mode, *colGraph);//node mode error message is : //---------------------------------------------------- c:\...\xxx.cpp(236) : error C2440: 'initializing' : cannot convert from 'boost::property_map<Graph,Property>::type' to 'boost::bundle_property_map<Graph,Descriptor,Bundle,T>' with [ Graph=boost::adjacency_list<boost::vecS,boost::vecS,boost::bidirectionalS,Node, Edge>, Property=double (Node::* )[3] ] and [ Graph=Graph, Descriptor=boost::property_map<Graph,double Node::* >::descriptor, Bundle=Node, T=double ] No constructor could take the source type, or constructor overload resolution was ambiguous //---------------------------------------------------- neither the following works(I added '[3]' in the parameter list): boost::property_map<Graph, double Node::*[3]>::type nm = get(&Node::mode, *colGraph);//node mode This time errors are raised in the 'property.hpp' file, they are: //---------------------------------------------------- c:\Boost\include\boost-1_33_1\boost\pending\property.hpp(40) : error C2825: 'PropertyTag::kind': cannot form a qualified name c:\Boost\include\boost-1_33_1\boost\graph\properties.hpp(198) : see reference to class template instantiation 'boost::property_kind<PropertyTag>' being compiled with [ PropertyTag=double Node::* [3] ] c:\shufei\VCProjects\edison\segm\GA.cpp(236) : see reference to class template instantiation 'boost::property_map<Graph,Property>' being compiled with [ Graph=Graph, Property=double Node::* [3] ] c:\Boost\include\boost-1_33_1\boost\pending\property.hpp(40) : error C2039: 'kind' : is not a member of 'operator``global namespace''' c:\Boost\include\boost-1_33_1\boost\pending\property.hpp(40) : error C2146: syntax error : missing ';' before identifier 'type' c:\Boost\include\boost-1_33_1\boost\pending\property.hpp(40) : error C2955: 'boost::type' : use of class template requires template argument list c:\Boost\include\boost-1_33_1\boost\type.hpp(14) : see declaration of 'boost::type' c:\Boost\include\boost-1_33_1\boost\pending\property.hpp(40) : fatal error C1903: unable to recover from previous error(s); stopping compilation //---------------------------------------------------- thanks, Shufei

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[mpl] insert not inserting?
by Scott Meyers 04 Apr '07

04 Apr '07

In my continuing effort to demonstrate my inability to get much of anything working with the MPL, I'm having trouble inserting a type into an existing set of types. The code compiles and runs, but the revised type sequence is empty. Here's the code: #include <boost/mpl/set.hpp> #include <boost/mpl/for_each.hpp> #include <typeinfo> #include <iostream> namespace mpl = boost::mpl; struct Base { virtual ~Base(){} }; struct A { virtual ~A(){} }; struct B { virtual ~B(){} }; struct Print { template<typename T> void operator()(const T&) { std::cout << typeid(T).name() << ", "; } }; int main() { typedef mpl::set<A, B> Constraints; // print contents of Constraints (should be the equivalent // of "[A, B,]") std::cout << '['; mpl::for_each<Constraints>(Print()); std::cout << "]\n"; // add Base to Constraints, call result BaseClasses typedef mpl::insert<Constraints, mpl::end<Constraints>, Base> BaseClasses; // print contents of BaseClasses (should be the equivalent // of "[A, B, Base, ]") std::cout << '['; mpl::for_each<BaseClasses>(Print()); std::cout << "]\n"; } Can anybody spot what I'm doing wrong? I know that I could use the two-argument form of insert with a set, but I'm trying to write code that will work with a vector, too, and at any rate, I get the same results with the two-argument form of set. Thanks, Scott

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Re: [Boost-users] [Serialization] issue withportable_binary_oarchive
by Pfligersdorffer, Christian 03 Apr '07

03 Apr '07

boost-users-bounces(a)lists.boost.org wrote: > Hi, > I have switched all the 0 pointer cases to use some Null object. > Now everything works fine. > Thanks very much for your help. > > One last (I hope) question: > > The compilation of this archive produce some compilation > warnings, how can I avoid it ? > > Thanks again, > Dan Leibovich Dear Dan & Robert, I read this thread with very much interest since I want to use the portable binary archive too. Could you please share your experience and especially the code of the version that actually works? Did you also add code to treat floating point types? Yours sincerely, -- DI Christian Pfligersdorffer Software Engineering EOS GmbH

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Typetraits for decomposing member function pointers?
by Tom Bachmann 02 Apr '07

02 Apr '07

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, is there a way to get more information about a member function pointer, using type traits, than is_member_function_pointer<T>::value? I'm looking for information about e.g. the constness and function_traits-like information. - -- - -ness- -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFGBs++vD/ijq9JWhsRApJNAJ9nbbZnRMnTMBi0l09yqBaCIiYGmgCfTjRO I12viJTyF3sUp0sICPR/nDg= =ym+h -----END PGP SIGNATURE-----

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[mpl] erase_key confusion
by Scott Meyers 02 Apr '07

02 Apr '07

I expect the following code to compile cleanly. It does not. #include <boost/mpl/set.hpp> #include <boost/mpl/equal.hpp> #include <boost/mpl/erase_key.hpp> namespace mpl = boost::mpl; using mpl::_1; using mpl::_2; struct A {}; struct B {}; typedef mpl::set<A, B> set1; typedef mpl::set<B, A> set2; BOOST_MPL_ASSERT(( mpl::equal< mpl::erase_key<set1, A>::type, mpl::erase_key<set2, A>::type > )); I'm simply trying to assert that the sets {A,B} and {B,A} have the same elements after A has been removed from both. What am I doing wrong? Thanks, Scott

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[graph] adjacency_list with edges in mulitsetS does not seem to sort
by Carsten Scholtes 02 Apr '07

02 Apr '07

Hello! I'm trying to use boost::graph's adjacency_list<listS, multisetS,...>. The documentation ( boost_1_33_1/libs/graph/doc/adjacency_list.html ) states for the function edge_range(): > This function only works when the OutEdgeList for the adjacency_list > is a container that sorts the out edges according to target vertex, > and allows for parallel edges. The multisetS selector chooses > such a container. Attached you find a small program demonstrating a case where edges do not seem to get sorted accordingly. The last comment in the program contains a sample output. * The line below "All edges" shows the sequence of all edges. It does not seem to be sorted in the specified way. Probably as a consequnce of this, edge_range() does not work as expected: * The last line of the output is generated by using edge_range(). It should output edges from node 1 to node 0. There is only one such edge. Instead of that, edges (1,2) and (1,0) are returned. Am I using the interface in a wrong way or is there an error in the implementation of adjacency_list<>? Thank you in advance for any comment or advice. Carsten Scholtes

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Building for cygwin on Windows?
by John Harper 01 Apr '07

01 Apr '07

I can't get the boost libraries to build correctly using Cygwin and GCC on Windows XP. Boost seems determined to build for some kind of native Windows environment. I'm trying: bjam "-sTOOLS=gcc" "--prefix=/usr/local" and it complains "wide i/o not supported on this platform". If I omit --prefix it puts the libraries in the Windows file system under C:\Boost, but even if I copy them to somewhere under cygwin and point GCC at them, it still doesn't find them. SUrely I'm not the first person to want to do this? What is the magic formula? Thanks...

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