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C++Builder and Boost Graph Library
by Guilherme Mello de Moura 26 Nov '03

26 Nov '03

Hi guys, My name is Guilherme and I'm trying to use Boost Graph Library with Borland C++Builder.. I'm getting several compilation errors.. I downloaded the latest BGL version (1.30.2) and tried to compile the first graph example I saw.. Here's what I got: Using Boost Graph Library (BGL) version 1.30.2 with C++Builder 5.0 (6.0).. [C++ Error] tuple_basic.hpp(158): E2434 Template declaration missing template parameters ('template<...>') [C++ Error] tuple_basic.hpp(158): E2238 Multiple declaration for 'element<N,T>' [C++ Error] tuple_basic.hpp(143): E2344 Earlier declaration of 'element<N,T>' I also tried to compile the example tests that come with BGL .. And I got some problems with some of them .. Has anybody had the same problem ?!?! Am I doing something wrong ?!?! Regards, Guilherme Mello de Moura

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unit_test_framework - redirect output
by Steven Ketcham 25 Nov '03

25 Nov '03

Perhaps I am making this difficult or even missing the point but... Can I create tests with the unit_test_framework and redirect the output to a GUI? As it stands this is not possible because of int main(...) being defined. Using Windows 2000. Thanks! -- Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

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[BGL] Using default_dfs_visitor on a graph with std::list as the vertex type
by sashan 25 Nov '03

25 Nov '03

I'm trying to use a vistitor class on a graph I have defined. The visitor class is very simple and inherits from default_dfs_visitor: class OpenGLVisitor : public boost::default_dfs_visitor { public: OpenGLVisitor(void); virtual ~OpenGLVisitor(void); }; My graph type is: typedef adjacency_list < vecS, listS, directedS > graph_t; The code to perform a dfs on the graph is as follows: graph_t g; depth_first_search(g, visitor(OGLVisitor)); However I get the compiler error (see attachment). If I change the typedef to typedef adjacency_list < vecS, vecS, directedS > graph_t; then there is no error. This seems odd since it should also work when the vertices of the graph use the std::list as their container class. I'm using VC++7.1.

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Using boost::lamba with a vector of shared_ptr's
by Allen Bierbaum 24 Nov '03

24 Nov '03

Hello all. I am having trouble with the boost lambda library. I am convinced that my troubles come from some little thing I am overlooking, but for the life of me I can't seem to find the problem. I have been looking at it for the entire afternoon with no solution in sight. I have included some sample code below showing the basic idea of what I am trying to accomplish. Can anyone provide me with a working solution? The summary is: - I have a vector of shared_ptr's to a class A - That class has a method that returns a value I would like to test for in a find_if call ============================================================ namespace bl = boost::lambda class A { int getInt(); }; class Foo { A bar(); } std::vector<shared_ptr<Foo> > foos; shared_ptr<Foo> foo_ptr; A test_val; test_val = (bl::_1 ->* &Foo::bar )(foo_ptr); int find_int = 10; iter found = find_if(foos.begin(), foos.end(), (bl::_1->* &Foo::bar).getInt() == child_guid); ==================================================================== Can anyone tell me how I can call a method from a lamda method iterating over a sequence of shared_ptrs? And then how do I have this method also call another method? Thanks, Allen

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regex question
by Paul Scruby 24 Nov '03

24 Nov '03

I have question about match_result. How can I find out what was matched from the regular expression? In the boost documentation, the example for regex_search does something similar to this... regex needle("foo|bar"); string haystack("blah bar blah"); string::const_iterator start = haystack.begin(); string::const_iterator end = haystack.end(); boost::match_results<string::const_iterator> what; *unsigned* *int* flags = boost::match_default; * while*(regex_search(start, end, what, expression, flags)) { // please output 'bar' string match(string(what[5].first, what[5].second) + std::string(what[6].first, what[6].second)); cout << "Found '" << match << "'\n"; start = what[0].second; flags |= boost::match_prev_avail; flags |= boost::match_not_bob; } However, this is outputing nothing. I also tried what.str(), but that gave me nothing too. Thanks again, Paul

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problem with lexical_cast<int>(std::wstring)
by Ronnie Lazar 24 Nov '03

24 Nov '03

Hi, I'm trying to use lexical_cast<int>(std::wstring), on msvc6 with STLPort, and I get compilation errors. The reason for them is that DISABLE_WIDE_CHARS_SUPPORT is defined in the beginning of lexical_cast.hpp. If I add a line to undef this, in the file, it compiles and works fine, which leads me to belice that this define sould not really be defined. I searched a little more and found that it is defined because BOOST_NO_INTRINSIC_WCHAR_T is defined. My understanding is that this define specifies that the environment does not have wchar_t as a real type, but as a typedef. Why should this interfere with lexical_cast? Any suggestions on how to work around this (apart from changing lexical_cast.hpp source at my site? Thanks Ronnie Lazar

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problem using function lib in MSVC6
by Kim 22 Nov '03

22 Nov '03

Boost version: 1.30.2 Boost Lib: Function OS: Windows XP Pro SP 1 Dev. Env.: Microsoft VS6 SP 6, .NET 2003 Platform SDK Feb 2003, DirectX9 SDK Problem: Can't get an example similar to the one found in the tutorial to work. // ************************************* #include <boost/function.hpp> #include <functional> struct X { int foo(int v) { return v;} }; int main(int argc, char* argv[]) { boost::function1<int, int> f; X x; f = std::bind1st ( std::mem_fun(&X::foo), &x ); f(5); // Call x.foo(5) return 0; } //*************************************** I get this error message: : error C2784: 'class std::mem_fun_t<_R,_Ty> __cdecl std::mem_fun(_R (__thiscall _Ty::*)(void))' : could not deduce template argument for '<Unknown>' from 'int (__thiscall X::*)(int)'

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Boost.Thread problem with thread_specific_ptr<>::release ?
by Roland 21 Nov '03

21 Nov '03

Dear Boosters! As I am still trying to figure out how to use the thread local storage pointer I found another strange behaviour. Perhaps I am misunderstanding the docs, or this might be a bug. System: VC6.0 CVS Head Problem: When using release on a tss variable, the associated automatic cleanup routine seems not to be updated correctly as it tries to delete the original pointer, instead of the 0-pointer. Example (simple modification of tss.cpp example): boost::thread_specific_ptr<int> value; void increment() { int* p = value.get(); ++*p; } void thread_proc() { value.reset(new int(0)); // initialize the thread's storage for (int i=0; i<10; ++i) { increment(); int* p = value.get(); assert(*p == i+1); } //******** added the following two lines int* p = value.release(); delete p; // deleting the released pointer //******* } int main(int argc, char* argv[]) { boost::thread_group threads; for (int i=0; i<5; ++i) threads.create_thread(&thread_proc); threads.join_all(); } In the debug version the program faults at exit, as the pointers are beeing freed a second time. I suspect the problem lies in the following function, as it does not set the cleanup handler if the value is 0 bool tss::set(void* value) { if (value && m_cleanup) { cleanup_handlers* handlers = get_handlers(); assert(handlers); if (!handlers) return false; cleanup_info info(m_cleanup, value); (*handlers)[m_key] = info; } return !!TlsSetValue(m_key, value); } Regards, Roland Schwarz

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When to use which functors?
by Bruce Johnston 21 Nov '03

21 Nov '03

I'm somewhat new to Boost, but pretty familiar with STL and Loki. I'm a bit puzzled by the wide array of similar-sounding libraries in Boost for dealing with function objects: Lambda, Function, Functional, and Bind/Mem_fn. Why are there so many of these libraries and under what circumstances would I want to choose one over the other? Thanks. - Bruce Johnston Simba Technologies

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RE: [Boost-users] lexical_cast causes level 4 warnings w/ VC7.1
by Sam Partington 21 Nov '03

21 Nov '03

Peter Dimov <mailto:pdimov@mmltd.net> wrote: > Sam Partington wrote: >> >> 4511 and 4512 are useless warnings. They are telling you that the >> copy constructor and assignment operator are inaccessible. Even >> though you're not trying to call them. [...] > >> C4127 is also awkward. As it gives warnings for some common idioms. >> It refers to conditional expressions being constant. > > These warnings can be annoying, but they aren't useless. They do find > bugs. I agree that 4127 can help you find bugs. But I can't think of any situation where 4511 or 4512 will help you find a bug. If you actually try to call an inaccesible copy constructor or assignement operator, then the compiler (correctly) fails to compile it. Thats why I used the word "awkward" rather than "useless" for 4127. I'll happily be proved wrong though. Sam ****************** This e-mail has been sent from Imagination Technologies Limited. PowerVR, Metagence, Ensigma and PURE Digital are divisions of Imagination Technologies Limited. The information contained in this e-mail, including any attachment, is confidential and may be legally privileged. It is intended solely for the addressee(s) and access to this e-mail by anyone else is unauthorised. If you are not the intended recipient, any disclosure, copying or distribution or use of the information contained in this e-mail, is prohibited and may be unlawful. If you have received this e-mail in error, please notify the sender by return e-mail and then delete it from your system. Internet communications cannot be guaranteed to be secure, error or virus-free. The sender does not accept liability for any errors or omissions which arise as a result. Any views expressed in this message are those of the author, except where the author specifies and, with authority, states them to be the views of Imagination Technologies Ltd.

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