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boost::bind questions
by Matt S Trentini 02 Sep '04

02 Sep '04

Heya Boosters, I ran into a problem using boost::bind yesterday and, although I found a workaround, I've got a few questions. For the record I'm using boost 1.30. I stumbled onto the issue that boost::bind doesn't define the argument_type typedef (I was trying to use std::not1). After trawling the web I found a discussion, and useful workaround, about this here: http://tinyurl.com/5bl9m Questions that arose from this: o Why doesn't boost::bind support argument_type? o What other standard library function adapters does this affect? - Is it all that are derived from unary_function? o Has the operator! addition been incorporated into later versions of boost? - If not, why not? Thanks! Matt

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There's someone using boost lu_substitute?
by yanyaqin 02 Sep '04

02 Sep '04

Hi folks, I'm ready to use boost lu_substitute for solving sparse symmetric linear equation, but the document for lu.hpp is almost none. Is there someone could provide me a real number demo? Best regards! Yan Yaqin 2004-09-02 ========================== 263电子邮件－信赖邮自专业

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ublas aix test failures
by Daniel Elliott 02 Sep '04

02 Sep '04

Hello, I am interested in using ublas for a large government project. I noticed ublas (as of 8-19-2004) failed test3 on the visual age c++ compiler. What does this test exercise? We have currently installed the 1.31 libraries. Is this the same code that produced the test results? Thank you for your time. Sincerely, Dan Elliott --------------------------------- Do you Yahoo!? Win 1 of 4,000 free domain names from Yahoo! Enter now.

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Preprocessor lib question wrt to vertical repetition
by Allen Gooch 02 Sep '04

02 Sep '04

Given the following #include <boost/preprocessor/repetition/enum_params.hpp> #ifndef TYPELIST_MAX_SIZE # define TYPELIST_MAX_SIZE 7 #endif template <BOOST_PP_ENUM_PARAMS(TYPELIST_MAX_SIZE, class T)> class ObjectImpl : BOOST_PP_ENUM_PARAMS(TYPELIST_MAX_SIZE, public T), public ObjectBase<REFCNTR> { public: virtual Refcount acquire() const { return Base::acquire(); } virtual Refcount release() const { return Base::release(); } virtual Refcount getRefcount() const { return Base::getRefcount(); } virtual bool hasInterface(InterfaceID const & iid) const { return Base::hasInterface(iid); } virtual IObject * getInterface(InterfaceID const & iid) { IObject const * const_this = (IObject const *) this; return (IObject *) const_this->getInterface(iid); } virtual IObject const * getInterface(InterfaceID const & iid) { IObject const * obj = 0; switch (iid) { case IObject::IID : { this->acquire(); obj = static_cast<IObject const *>(this); break; } // Desired: for each type T in typelist generate the following case block // case T::IID : // { // this->acquire(); // obj = static_cast<T const *>(this); // break; // } default : { throw InterfaceUnsupportedException(iid) break } } return obj; } protected: ObjectImpl() { } virtual ~ObjectImpl() { } typedef ObjectBase<REFCNTR> Base; }; What is the best way to generate a case block for each type in the typelist? I've been looking at the Preprocessor appendix from the "C++ Template Metaprogramming" book (can't wait!) and see three different approaches to vertical repetition: local, file and self; however, I'm not clean on how to express what I want using these approaches. Can someone shed some light, or point me to an example in the Boost PP docs which solves a similar problem? Many thanks in advance. -allen

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Another lambda question
by Maximilian Wilson 01 Sep '04

01 Sep '04

I am getting another compiler error when trying to use the lambda library. Current experiment is string extraction. I'm trying to create a lambda(x) that pushes any char passed to it onto a particular string. string s2; void (std::string::*ft)(char) = &std::string::push_back; // extract function pointer because push_back is overloaded char c = 'n'; bind<void>(ft, var(s2), _1, 1)(c); // should push one 'n' onto the string. However, it doesn't compile bind<void>(reinterpret_cast<char(std::string::*)(char)>(ft), var(s2), _1, 1)(c); // error messages made me think it might be because push_back returns void // I know this isn't good practice, but I'm just trying to figure out what's wrong // However, this won't compile either. And then I get this error /users/user2/ugrad/m/mdw45/boost_1_31_0/boost/lambda/detail/actions.hpp:109: error: no matching function for call to `boost::lambda::function_adaptor<char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*)(char)>::apply(char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const&)(char), std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, char&, const int&)' I'm not really sure what the real problem is. Can you tell from looking at the error message what I should be doing? Thanks in advance Max Wilson (FULL ERROR TEXT FOLLOWS) /usr/include/boost/lambda/detail/actions.hpp: In static member function `static RET boost::lambda::function_action<4, T>::apply(A1&, A2&, A3&, A4&) [with RET = void, A1 = char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const)(char), A2 = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, A3 = char, A4 = const int, T = void]': /usr/include/boost/lambda/detail/lambda_functor_base.hpp:442: instantiated from `RET boost::lambda::lambda_functor_base<boost::lambda::action<4, Act>, Args>::call(A&, B&, C&, Env&) const [with RET = void, A = char, B = const boost::tuples::null_type, C = const boost::tuples::null_type, Env = const boost::tuples::null_type, Act = boost::lambda::function_action<4, void>, Args = boost::tuples::tuple<char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const)(char), const boost::lambda::lambda_functor<boost::lambda::identity<std::string&> >, const boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>]' /usr/include/boost/lambda/detail/lambda_functors.hpp:151: instantiated from `typename T::sig<boost::tuples::tuple<A&, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >::type boost::lambda::lambda_functor<Base>::operator()(A&) const [with A = char, T = boost::lambda::lambda_functor_base<boost::lambda::action<4, boost::lambda::function_action<4, void> >, boost::tuples::tuple<char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const)(char), const boost::lambda::lambda_functor<boost::lambda::identity<std::string&> >, const boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >]' proj1.cpp:180: instantiated from here /usr/include/boost/lambda/detail/actions.hpp:109: error: no matching function for call to `boost::lambda::function_adaptor<char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*)(char)>::apply(char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const&)(char), std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, char&, const int&)' /usr/include/boost/lambda/detail/actions.hpp:109: error: return-statement with a value, in function declared with a void return type bash-2.05b$ g++ proj1.cpp -I /users/user2/ugrad/m/mdw45/boost_1_31_0 /users/user2/ugrad/m/mdw45/boost_1_31_0/boost/lambda/detail/actions.hpp: In static member function `static RET boost::lambda::function_action<4, T>::apply(A1&, A2&, A3&, A4&) [with RET = void, A1 = char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const)(char), A2 = std::basic_string<char, std::char_traits<char>, std::allocator<char> >, A3 = char, A4 = const int, T = void]': /users/user2/ugrad/m/mdw45/boost_1_31_0/boost/lambda/detail/lambda_functor_base.hpp:442: instantiated from `RET boost::lambda::lambda_functor_base<boost::lambda::action<4, Act>, Args>::call(A&, B&, C&, Env&) const [with RET = void, A = char, B = const boost::tuples::null_type, C = const boost::tuples::null_type, Env = const boost::tuples::null_type, Act = boost::lambda::function_action<4, void>, Args = boost::tuples::tuple<char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const)(char), const boost::lambda::lambda_functor<boost::lambda::identity<std::string&> >, const boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type>]' /users/user2/ugrad/m/mdw45/boost_1_31_0/boost/lambda/detail/lambda_functors.hpp:151: instantiated from `typename T::sig<boost::tuples::tuple<A&, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >::type boost::lambda::lambda_functor<Base>::operator()(A&) const [with A = char, T = boost::lambda::lambda_functor_base<boost::lambda::action<4, boost::lambda::function_action<4, void> >, boost::tuples::tuple<char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const)(char), const boost::lambda::lambda_functor<boost::lambda::identity<std::string&> >, const boost::lambda::lambda_functor<boost::lambda::placeholder<1> >, const int, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type, boost::tuples::null_type> >]' proj1.cpp:180: instantiated from here /users/user2/ugrad/m/mdw45/boost_1_31_0/boost/lambda/detail/actions.hpp:109: error: no matching function for call to `boost::lambda::function_adaptor<char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*)(char)>::apply(char (std::basic_string<char, std::char_traits<char>, std::allocator<char> >::*const&)(char), std::basic_string<char, std::char_traits<char>, std::allocator<char> >&, char&, const int&)' /users/user2/ugrad/m/mdw45/boost_1_31_0/boost/lambda/detail/actions.hpp:109: error: return-statement with a value, in function declared with a void return type -- Sometimes I think decisions through, weigh the consequences, decide it is not a good idea, but blind myself and make it anyway. I do not think this is a good thing to do, but it might be. Humans are endowed with both reason and emotion for a reason. -Tara Greenwood

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boost::graph adding verticies and edges whilst performing a dfs
by Daren Grant 01 Sep '04

01 Sep '04

Greetings all , I have a quick question regarding the boost graph library and depth first search operations. I have a very large graph , which has a visitor attached to the depth_first_search routine. The Visitor may add in more verticies / Edges when visiting an existing vertex in the Graph. (NOTE :: All the added verticies / edges from the visitor are guaranteed to be higher in the graph structure! i.e. the DFS algorithm would not have processed them at time of insertion. ) My question is can the depth_first_search handle changes to the Graph whilst it is performing its operation ? From my observations of the colour map used I dont think this is possible with the core depth_first_search routine in the library , could someone confirm this , and if anyone has ideas on how this can be performed I would be most grateful to hear their thoughts !

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Guidelines for effective exception usage
by Stephen torri 01 Sep '04

01 Sep '04

Are there any guidelines on where and when to use exceptions? Are there any boost components that deal with exceptions? Stephen -- Email: storri(a)torri.org

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internal properties and subgraphs.
by Jeffrey Holle 31 Aug '04

31 Aug '04

I've been experimenting with subgraphs. At present, they look quite useful in what I'm trying to do, but I've questions. If I add custom vertex and edge properties to my base graph, can I access these through a subgraph, using local vertex/edge descriptors? If not, is there a way of obtaining the mapping between global and local vertex/edge descriptors?

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interal properites with boost.graph question
by Jeffrey Holle 31 Aug '04

31 Aug '04

I've apparently succeeded in switching from external to internal properites in my application. However, I've done things in an OOP way, and would like to know if somebody can point out potential trouble. I've a class, called Graph, that inherits from the boost::graph object. The start of its definition is: class Graph : public GraphT { public: Graph(); // Graph Data accessor methods typedef boost::property_map<GraphT, vertex_Datum_t>::type VertexData; typedef boost::property_map<GraphT, edge_Datum_t>::type EdgeData; const VertexData& getVertexData(void) const {return vertexData_;} ... private: VertexData vertexData_; }; Note the typedef of VertexData. I initialize vertexData_ in the Graph constructor like this: vertexData_ = boost::get(vertex_Datum, *this); I've numerous methods like this in Graph: Vertex DataGraph::add_vertex(LayoutVertex *pLayoutVertex) { Vertex vertex = boost::add_vertex(*this); boost::put(vertexData_,vertex,Vertex_Datum(pLayoutVertex)); return vertex; } I guess my biggest concern is initializing vertexData_ once, before the graph has any data, and keeping it around though the life of the graph. Is this safe? Also, I expect clients of this class to be able to use the operator[] method via getVertexData(). Will this work?

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problem compiling with threads and stlport
by Nicholas Cain 31 Aug '04

31 Aug '04

hi, I'm new to boost, stlport and programming on linux in general, so I apologise now for any obvious beginner errors! I'm using mandrake 10 and gcc 3.3.2, and using root I created STLport 4.6.2 libraries, and then created all the boost 1.31.0 libraries using bjam -sTOOLS=gcc-stlport -sBUILD="debug release <stlport-iostream>on" install I had to have this little lot in my bashrc file to do it; export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib export STLPORT_VERSION=4.6.2 export STLPORT_ROOT=/home/ncain export STLPORT_LIB_DIRECTORY=/usr/local/lib export STLPORT_INCLUDE_DIRECTORY=/usr/local/include/ export PYTHON_VERSION=2.3 export PYTHON_ROOT=/usr Everything seemed to build ok, apart from an "../lib/libstlport_gcc_debug.so does not exist" error in the final part of the stlport build and a continual "warning: "_POSIX_C_SOURCE" redefined" warning during the boost build. Both the stlport and boost libraries are in /usr/local/lib ok, and building thread/test passed fine too. I altered one of the tutorial files to use _STL and also created a makefile (since bjam is a bit beyond me at the moment), and these appear as; testboost.cpp: #include <boost/thread/thread.hpp> #include <boost/thread/xtime.hpp> #include <iostream> using namespace _STL; struct thread_alarm { thread_alarm(int secs) : m_secs(secs) { } void operator()() { cout << "alarm sounded..." << endl; } int m_secs; }; int main(int argc, char* argv[]) { int secs = 5; thread_alarm alarm(secs); boost::thread thrd(alarm); thrd.join(); } makefile: .PHONY: all clean ALL = testboost INCS = -I"/usr/local/include/stlport" \ -I"/usr/local/include/boost-1_31" LIBS=-L"/usr/local/lib" -lstlport_gcc -lboost_thread-gcc-mt-p -lpthread .cpp: ${CXX} ${INCS} -pthread -o $@ $^ ${LIBS} all: ${ALL} clean: ${RM} core* *.o ${RM} ${ALL} make returns this error; g++ -I"/usr/local/include/stlport" -I"/usr/local/include/boost-1_31" -pthread -o testboost testboost.cpp -L"/usr/local/lib" -lstlport_gcc -lboost_thread-gcc-mt-p -lpthread /home/ncain/tmp/ccZWBPnj.o(.text+0x4b): In function `main': : undefined reference to `boost::thread::thread[in-charge](boost::function0<void, _STL::allocator<boost::function_base> > const&)' collect2: ld returned 1 exit status make: *** [testboost] Error 1 using -lboost_thread-gcc-mt-gdp makes no difference, however changing the cpp to use the std libraries works fine (builds and runs correctly). Have I made a mistake in building the boost libraries or possibly in my makefile? thanks, nik

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