November 2002 - Boost-users

Can't use adjacency_list AND adjacency_matrix in same program
by loopylozzysdad 07 Nov '02

07 Nov '02

Hi, It seems to me that you can't use adjacency_list AND adjacency_matrix in the same program. When I had both the relevant inludes in the program I got duplicate definition errors from the linker. Is this by design, or a bug? Cheers - Richard Howells (loopylozzydad at yahoo dot com)

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RE: [Boost-Users] shared_ptr capabilities
by Mark Storer 06 Nov '02

06 Nov '02

>I don't believe the above statement will affect me, >but I just want to be sure Correct. A language-level array is not an STL container. There IS a shared_ptr-like template called shared_array that calls "delete []" instead of "delete". Had to look that one up. It doesn't get used much. std::vector is a superior choice (in every situation I can think of). An STL container of shared_ptr's is just fine. Just don't create a circular reference. --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typedef std::disclaimer<Cardiff> Discard; -----Original Message----- From: Collin Peters [mailto:yg-boost-users@m.gmane.org] Sent: Wednesday, November 06, 2002 1:04 PM To: boost-users(a)yahoogroups.com Subject: [Boost-Users] shared_ptr capabilities http://www.boost.org/libs/smart_ptr/shared_ptr.htm states that: "Normally, a shared_ptr cannot correctly hold a pointer to a dynamically allocated array. See shared_array for that usage." What I hope to use shared_ptr for, is to store pointers to a class in a vector, and that class will also have a vector that stores pointers via shared_ptr. example: class Foo { int a; } class one { int var1; int var2; std::vector<Foo> foo_vector; } class two { std::vector<one> one_vector; } I don't believe the above statement will affect me, but I just want to be sure Collin Peters Info: <http://www.boost.org> Wiki: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl> Unsubscribe: <mailto:boost-users-unsubscribe@yahoogroups.com> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

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shared_ptr capabilities
by Collin Peters 06 Nov '02

06 Nov '02

http://www.boost.org/libs/smart_ptr/shared_ptr.htm states that: "Normally, a shared_ptr cannot correctly hold a pointer to a dynamically allocated array. See shared_array for that usage." What I hope to use shared_ptr for, is to store pointers to a class in a vector, and that class will also have a vector that stores pointers via shared_ptr. example: class Foo { int a; } class one { int var1; int var2; std::vector<Foo> foo_vector; } class two { std::vector<one> one_vector; } I don't believe the above statement will affect me, but I just want to be sure Collin Peters

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Q: Problems building boost.python under cygwin
by "Schnörr, Claudius Dr." 06 Nov '02

06 Nov '02

Hello, I run into problems building boost under cygwin. It seems to be merely a matter of a wrong configuration or wrong scripts. After running 'bjam -sTOOLS=gcc -n > build.com' in boost/libs/python/build in order to get hands on the statements being executed by bjam, there had to be made a lot of textual replacements to get the statements in build.com run: Just to mention some: - replace '-isystem ' by '-I' - remove '-I""' - change shared library-names from *.so to *.dll - insert '-L <path_to_libpython2.2.dll> -lpython2.2' where shared libs are created In boost/libs/python/test, going the same way, there have in addition this changes to be made: - LD_LIBRARY_PATH=... --> PATH=$PATH:..., because cygwin uses PATH to look for .dlls My question: I think there have to be made more configurations than I did to create the boost.python-stuff under cygwin. Where have they to be done, and what? (I already configured environment variables like GCC_ROOT_DIRECTORY, GXX, PYTHON_ROOT, ...etc...) Any suggestions are welcome! Please send a copy of your answer to schnoerr(a)mailzone.com Thank you in advance, Claudius --------------------------------------------------------- This Mail has been checked for Viruses Attention: Encrypted mails can NOT be checked! ** Diese Mail wurde auf Viren geprueft Hinweis: Verschluesselte mails koennen NICHT auf Viren geprueft werden! ---------------------------------------------------------

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RE: [Boost-Users] set thread priority
by Mark Storer 05 Nov '02

05 Nov '02

I'd think you could get away with something like a set range, like 0 to 1000, and then map those values into whatever system is present. You could even use floating point values, 0.0 to 1.0, though people might look at you cross-eyed, at least until they got used to the idea. Then it's just a matter of mapping those ranges to whatever OS settings are present. You just state up front a couple caveats: Given two threads, A (higher priority) and B (lower priority), you only guarentee that A won't be given a lower underlying system priority than B. This would save you quite a bit of grief... particularly when someone wants threads with priority 1.0, 0.99 and 0.98. The thread with 0.98 might not run slower than the one with a 1.0 priority, but it certainly won't be faster. SOUNDS simple enough. At least to someone whose sum total multi-threading experience is a toy java applet and a dozen lines of boost::thread code. ;) --Mark Storer Software Engineer Cardiff Software #include <disclaimer> typedef std::disclaimer<Cardiff> Discard;

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set thread priority
by boxerab 05 Nov '02

05 Nov '02

Dear Boost Users, I am considering using the boost thread library; currently I use the Win32 API for threading on Windows. Is it possible to set the thread priority of a boost thread? Thanks! Aaron Boxer boxerab(a)NOSPAMyahoo.com

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can't compile johnson-eg.cpp with VC6
by chul_de_condares 05 Nov '02

05 Nov '02

I get the following errors when trying to compile the example code for johnson_all_pairs_shortest_paths. Has anyone ever seen this before? Thanks in advance. d:\swapps\source\axrt\c\boost\boost_1_29_0 \boost\graph\johnson_all_pairs_shortest.hpp(61) : error C2899: typename cannot be used outside a template declaration d:\swapps\source\axrt\c\boost\boost_1_29_0 \boost\graph\johnson_all_pairs_shortest.hpp(166) : see reference to function template instantiation 'bool __cdecl boost::johnson_all_pairs_shortest_paths(class boost::adjacency_list<struct boost::vec S,struct boost::vecS,struct boost::directedS,struct boost::no_property,struct boost::property<enum boost::edge_weight_t,int,struct boost::property<enum boost::edge_weight2_t,int,struct boost::no_property> >,struct boost::no_property,struct boost::li stS> &,int (&)[5][5],struct boost::vec_adj_list_vertex_id_map<struct boost::no_property,unsigned int>,struct boost::adj_list_edge_property_map<struct boost::directed_tag,int,int const &,unsigned int,struct boost::property<enum boost::edge_weight_t,i nt,struct boost::property<enum boost::edge_weight2_t,int,struct boost::no_property> > const ,enum boost::edge_weight_t>,int)' being compiled d:\swapps\source\axrt\c\boost\boost_1_29_0 \boost\graph\johnson_all_pairs_shortest.hpp(84) : error C2899: typename cannot be used outside a template declaration d:\swapps\source\axrt\c\boost\boost_1_29_0 \boost\graph\johnson_all_pairs_shortest.hpp(166) : see reference to function template instantiation 'bool __cdecl boost::johnson_all_pairs_shortest_paths(class boost::adjacency_list<struct boost::vec S,struct boost::vecS,struct boost::directedS,struct boost::no_property,struct boost::property<enum boost::edge_weight_t,int,struct boost::property<enum boost::edge_weight2_t,int,struct boost::no_property> >,struct boost::no_property,struct boost::li stS> &,int (&)[5][5],struct boost::vec_adj_list_vertex_id_map<struct boost::no_property,unsigned int>,struct boost::adj_list_edge_property_map<struct boost::directed_tag,int,int const &,unsigned int,struct boost::property<enum boost::edge_weight_t,i nt,struct boost::property<enum boost::edge_weight2_t,int,struct boost::no_property> > const ,enum boost::edge_weight_t>,int)' being compiled Error executing cl.exe. test.obj - 2 error(s), 0 warning(s)

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Boost Python v2 - extending and embedding - memory leaks, compiler warnings
by texrmex 05 Nov '02

05 Nov '02

First, I'm excited about the new work that's been done with Boost Python v2. I can't wait to see if it's enough to overcome the pitfalls that prevented me from getting past the evaluation stage with v1. I'm using VC7 IDE to build my project and link to python22.lib and boost_python.lib (built with VC7 command line tools using bjam). I'm attempting to extend and embed in my existing project, so I'm not building a dll, but and exe. First of all, can I do this? When it links it says "Creating library ....lib and object ....exp", and still creates an exe. If I don't include my test module (and thus boost/python.hpp) I don't get this message. I'm assuming that by defining a module, boost defines exports and the linker then creates the lib and exp, since there were exports? Although I've built dlls before, I really don't know the inner workings of the process. The following is a brief example of my module. At the bottom is a simple test function that I'm calling just to test importing of the module. When I call TestModule(), I get 2 memory leaks from the module definition section, one from the class definition, and the other from the method definition. If I remove these, I get no memory leaks, and if I add more classes and methods, I get one 12 byte leak per class and one 12 byte leak per method I add. I do not get a leak from defining the top level function "greet". /////////////////////////////////////////////////// #include <boost\python.hpp> using namespace boost::python; namespace { const char * greet() { return "Hello World"; } class CSimple { public: bool Test() { return true; } }; }; BOOST_PYTHON_MODULE(Test) { def("greet", greet); class_<CSimple>("Simple") .def("Test", &CSimple::Test) ; } void TestModule() { Py_Initialize(); initTest(); Py_Finalize(); } /////////////////////////////////////////////////// In addition to the memory leaks, I get a number of compiler warnings, similar to the following: d:\Boost\boost\python\instance_holder.hpp(18) : warning C4275: non dll-interface class 'boost::noncopyable' used as base for dll- interface struct 'boost::python::instance_holder' d:\Boost\boost\utility.hpp(50) : see declaration of 'boost::noncopyable' d:\Boost\boost\python\instance_holder.hpp(17) : see declaration of 'boost::python::instance_holder' *and* d:\Boost\boost\python\detail\exception_handler.hpp(34) : warning C4251: 'boost::python::detail::exception_handler::m_impl' : class 'boost::function2<R,T0,T1,Policy,Mixin,Allocator>' needs to have dll-interface to be used by clients of struct 'boost::python::detail::exception_handler' with [ R=bool, T0=const boost::python::detail::exception_handler &, T1=const boost::function0<void,boost::empty_function_policy,boost::empty_functi on_mixin,int> &, Policy=boost::empty_function_policy, Mixin=boost::empty_function_mixin, Allocator=int ] I was wondering if my project is not set up properly, and if these warnings might have something to do with the memory leaks. In v1 there was a vc project you could use for building boost python. This works well if you are planning on linking to a vc built project, since you can make sure your settings, paths and libs are consistent between the boost python lib and your project. I currently have 3 different sets of build tools (yes, 3 compilers) on this box, with several different versions of standard and other libraries, so making sure I have control of the paths and settings used is very important. This is one reason I'm weary of the jam environment. It's yet another build environment, one that I'm not familiar with, and one that I'm not going to be using with any other projects except to build boost python. So a question would be: how easy would it be for me to set up a VC project for building boost python? Has this already been done? Or am I barking up the wrong tree? Thanks in advance, -Tex

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RE: [Boost-Users] Iterator Adaptor Question
by Hickman, Greg 04 Nov '02

04 Nov '02

> -----Original Message----- > From: Mark Storer [mailto:mstorer@cardiff.com] > > You wrote up your sample so anyone could easily compile it... Thanks for noticing. :) > On > VC++ v6, I got two compiler errors: > > samplecode.cpp(58) : error C2663: 'reset' : 2 overloads have > no legal conversion for 'this' pointer > samplecode.cpp(59) : error C2678: binary '=' : no operator > defined which takes a left-hand operand of type 'const class > boost::shared_ptr<struct Shape const >' (or there is no > acceptable conversion) > > These errors are on the two lines you want to prevent. > > My first impression of the code was that it was already > illegal to perform those two actions. You shouldn't be able > to call non-const functions through a const_iterator, and > since neither reset() nor operator=() are const, no problem. > Right? I wasn't expecting the first error message, but the > second is in line with my expectations. > > I take it this code compiles for you? What tools/OS/etc are > you using? Unfortunately it does. I'm using Borland C++ Builder 5, for which I believe I have all of the available patches installed. (I'm using the IDE, but my command-line tells me I'm using Borland C++ 5.5.1. Borland gives away a set of free command-line tools that are distinct from the Builder IDE, and it may be that the compiler they give away is now more compliant than the one included in C++ Builder 5. If there is a way to point my IDE at the latest version of the free compiler, I don't know how to do it. I need to get gcc set up on my machine as a sanity check.) My first thought was that iterator_adaptor might be stripping away the const-ness from reference_type<const Const_shape_ptr>, and that the pointer type being generated was somehow pointing to a non-const Const_shape_ptr, thus allowing the indicated lines to compile. However, since you seem to get the desired results, perhaps the problem is with my compiler (or with Boost's support of it). Thanks very much for taking the time to respond. -Greg Hickman

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Property maps
by Edward Diener 04 Nov '02

04 Nov '02

The documentation for boost::property_map is awful, so would someone please explain to me what this implementation does and how it differs from std::map<> and std::multi_map<> ? I know this post sounds irascible and I am not trying to dump on Mr. Siek but really I do not understand what this idea is or why one should use it over and above what already exists in the C++ standard library. I only wish that Boost implementors would stop explaining their ideas through examples and start explaining them in logical ways in which a knowledge of the English language would suffice.

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