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compile 1_32 on darwin fails for test library (unit_test, prg_exec_monitor, etc)
by John A Meinel 12 Jan '05

12 Jan '05

I'm currently trying to compile all of boost on OS X (10.3.7), using TOOLS=darwin. I already read about the problems with xml_grammar, so I just added: #ifdef NDEBUG template class basic_xml_grammer<char>; #endif //NDEBUG This at least lets the compilation finish. And I'm not using boost::serialization yet. Hopefully Apple will get a fix (I am compiling with their latest build 1671). But I'm running into another problem during the link stage of the test libraries "libboost_unit_test_framework.dylib" It happens in both debug and release builds, I get: ld: Undefined symbols: init_unit_test_suite(int, char**) I found this function defined in auto_unit_test.hpp, and referenced in some of the .cpp files. Now, I'm guessing that this might be intentionally undefined, so that when you bind to the dynamic library, you define your own initialization (probably through a macro), and the library uses that. Has anyone else had this problem? I tried looking through the regression tests, but I haven't found anything that looks like this problem. I saw this post on the mailing list: http://thread.gmane.org/gmane.comp.lib.boost.user/6489 But there were no follow-ups, so I decided to re-post. Is this just a problem with dynamic libraries on Mac, that they can't have undefined symbols? Or is it something else? If it just means that you can only use the static library, that's fine. But why is it compiling the dynamic ones on Mac if they won't succeed? Thanks, John =:->

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Re: size of libboost_thread-gcc-mt.so
by Vladimir Prus 12 Jan '05

12 Jan '05

Alexander Nasonov wrote: > Amerio wrote: >> Hello, >> After compiling libboost_thread-gcc-mt.so on debian/gcc-2.95.4, this so >> weights 195kB, while libpthread weights only 100kB. >> Why such a huge difference ? Isn't boost::thread meant to be as >> lightweight as possible ? > > Try building it with Boost.Build v2 (bjam --v2 gcc release). It's only > 64K because read_write_mutex.o (223K in release) is excluded from link. > I don't know whether it's intentional or an oversight. I'm afraid it's an oversight -- that's a recently added feature. I'm surprised that it adds so much to the size though, let me try here. Without read_write_mutex the size of gcc/release/shared build is 46K. With read_write_mutex the size is 136K. Wow, that's a difference! When I comment out explicit template instantiations in that source file, the library is becomes 76K. The comment says explicit instantination are needed to detect syntax errors in templates but those instantination bloat the library. BTW, I'm not sure read_write_mutex should be a template, either. Maybe, we need class polymorphic_mutex; and template<class Mutex> class concrete_polymorphic_mutex : public polymorphic_mutex { }; and read_write_mutex_impl must be implemented in terms of polymorphic_mutex? - Volodya

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B is_convertible to A<T> for some T
by Agoston Bejo 12 Jan '05

12 Jan '05

Hello, how do I express through template metaprogramming or in a similar way that a class is convertible to a template class for some T1? I.e., the condition: "There exists some T1 such that B is convertible to A<T1>". An example program: (Platform: VC++7.1) --------------------------------------------------- #include <iostream> #include <boost/utility/enable_if.hpp> using namespace std; using namespace boost; template<typename T> struct A {}; struct B : public A<int> {}; template<typename T> struct isA { static const bool value = false; }; template<typename T> struct isA< A<T> > { static const bool value = true; }; // This would give the desired result, but I don't know how it should // legally be expressed it in C++ (if anyhow): //template<typename T, typename TEnabler = void> //struct A { static const bool value = false; }; // //template<typename T, > //struct isA< T, // enable_if<{{T where T is convertible to A<T1> for some T1}}> > //{ // static const bool value = true; //}; int _tmain(int argc, _TCHAR* argv[]) { cout << isA< A<int> >::value << endl; // 1 cout << isA< A<double> >::value << endl;// 1 cout << isA< B >::value << endl; // 0 - not what I want cout << isA<int>::value << endl; // 0 return 0; } ---------------------------------------------------

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Boost Graph Reading and Writing ATT graphviz example compile error
by Welson Sun 12 Jan '05

12 Jan '05

Hi, My platform is Linux (Fedora Core 2), gcc version: gcc (GCC) 3.3.3 20040412 (Red Hat Linux 3.3.3-7) I need to read and write the ATT graphviz format, so this is what I did: 1. Generated the libbgl-viz library. In boost_1_32_0/libs/graph/src/ directory, use the default Makefile, generated the libbgl-viz library without error. And I copied them to /usr/local/lib 2. g++ boost_1_32_0/libs/graph/example/graphviz.cpp, but I got the nasty error: ccVhyZaG.o(.text+0x602):graphviz.cpp: undefined reference to `boost::read_graphviz(std::basic_string<char, std::char_t raits<char>, std::allocator<char> > const&, boost::subgraph<boost::adjacency_lis t<boost::vecS, boost::vecS, boost::directedS, boost::property<boost::vertex_attr ibute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocator <char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > , std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, s td::allocator<char> > const, std::basic_string<char, std::char_traits<char>, std ::allocator<char> > > > >, boost::no_property>, boost::property<boost::edge_attr ibute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocator <char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > , std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, s td::allocator<char> > const, std::basic_string<char, std::char_traits<char>, std ::allocator<char> > > > >, boost::property<boost::edge_index_t, int, boost::no_p roperty> >, boost::property<boost::graph_graph_attribute_t, std::map<std::basic_ string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<c har, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string <char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pai r<std::basic_string<char, std::char_traits<char>, std::allocator<char> > const, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, bo ost::property<boost::graph_vertex_attribute_t, std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::cha r_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::c har_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::basic_ string<char, std::char_traits<char>, std::allocator<char> > const, std::basic_st ring<char, std::char_traits<char>, std::allocator<char> > > > >, boost::property <boost::graph_edge_attribute_t, std::map<std::basic_string<char, std::char_trait s<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char >, std::allocator<char> > >, std::allocator<std::pair<std::basic_string<char, st d::char_traits<char>, std::allocator<char> > const, std::basic_string<char, std: :char_traits<char>, std::allocator<char> > > > >, boost::property<boost::graph_n ame_t, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, b oost::no_property> > > >, boost::listS> >&)' collect2: ld returned 1 exit status What's the matter?

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bug in mersenne twister
by Morgan 11 Jan '05

11 Jan '05

This is my first bug report(ever), so feel free to point out how I could do a better job of this... Anyways I have found a bug with the mersenne_twister random number generator class, where results when calling for a random number vary between codewarrior 9.0 and gcc 3.4.1 with boost 1.31.0. A simple example is shown below: #include <boost/random/mersenne_twister.hpp> // for mt11213b typedef boost::mt11213b base_generator_type; class foo { public: foo(const base_generator_type gen):m_gen(gen) {} ~foo(void) {} rand_type operator() ( void ) { const float x = m_gen(); return x; } private: base_generator_type m_gen; } int main(void) { base_generator_type gen( (uint32_t) 2000); seed is not important foo f(gen); cout << "Random result is " << f() << endl; } The resulting numbers will be different between codewarrior 9.0 running on windows and gcc 3.4.1 running on Suse linux 7.3.(Hope that is enough info). I tracked the cause of the bug down to class initialization. In the case of CW9.0, the compiler when constructing a foo, will use a mersenne_twister copy ctor when initializing m_gen, while in the case of gcc 3.4.1 it will choose the following in the .hpp file template<class Generator> explicit mersenne_twister(Generator & gen) { seed(gen); } therefore using the provided generator as a seed to the new generator rather than just copying its state, even though no template parameter is provided. Anyways I will leave it up to the more informed to decide which is more desirable/proper; however, this is a fairly nasty bug at the moment as

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How can I uninstall Boost with bjam?
by Welson Sun 11 Jan '05

11 Jan '05

I tried "bjam uninstall", but doesn't work. I searched the web and maillist, looks like no one has ever talked about it. Yours, Welson Sun

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Serialization and shared_ptr
by Jarl Lindrud 11 Jan '05

11 Jan '05

Hi! A question on serializing pointers to derived classes: When I serialize naked polymorphic pointers through base pointers, things work as expected, ie the derived classes are serailized and deserialized. However, when I replace the naked pointers with corresponding boost::shared_ptr's, I get an archive_exception, to the tune of "unregistered class". I'm using BOOST_CLASS_EXPORT, and not the register_type<> functions. Is this supposed to happen, or do I need some additional type registration beyond what was necessary for serializing naked pointers? Thanks! Jarl. The code: //B and C derive from A std::ostringstream os; boost::archive::text_oarchive oa(os); //A *pb0 = new B(15,16); //A *pc0 = new C(17, 18, 19); boost::shared_ptr<A> pb0( new B(15,16) ); boost::shared_ptr<A> pc0( new C(17, 18, 19) ); oa << pb0; oa << pc0; std::string data = os.str(); { std::istringstream is(data); boost::archive::text_iarchive ia(is); //A *pa1 = NULL; //A *pa2 = NULL; boost::shared_ptr<A> pa1; boost::shared_ptr<A> pa2; ia >> pa1; ia >> pa2; B* pb = dynamic_cast<B *>(pa1.get()); C* pc = dynamic_cast<C *>(pa2.get()); } _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/

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Forwarding problem in base_from_member
by Jens Theisen 11 Jan '05

11 Jan '05

Hello, the above class (doesn't?) currently addresses the forwarding problem by passing constructor argument by value. Would it not be a better idea to use const&? We can't pass variable references at the moment, can we? Cheers, Jens

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RE: [Boost-users] Re: C++ Template Metaprogramming - Exercise 2-0
by Trask, Bruce (US SSA) 11 Jan '05

11 Jan '05

Philippe, > Given that, it is trivial to modify Eric's solution to have the > proper result. > Right. As they say in New England, Dawn in beginning to break over Marblehead. It took me four cracks to get it, but I think I got it now (see below and tell me if I do). (thanks for not telling me the answer outright) I starting to get the hang of it. Exercise 2.0 down. That's one in a row :) #include <iostream> #include <boost/type_traits/is_reference.hpp> #include <boost/type_traits/add_reference.hpp> #include <boost/type_traits/add_const.hpp> #include <boost/type_traits/is_same.hpp> #include <boost/static_assert.hpp> using namespace std; template<typename T> struct add_const_ref { typedef typename boost::add_reference<typename boost::add_const<T>::type>::type type; }; int main() { BOOST_STATIC_ASSERT((boost::is_same<boost::add_const<int>::type, const int>::value)); BOOST_STATIC_ASSERT((boost::is_same<boost::add_reference<int>::type, int&>::value)); BOOST_STATIC_ASSERT((boost::is_same<boost::add_const<int&>::type, int&>::value)); BOOST_STATIC_ASSERT((boost::is_same<boost::add_reference<boost::add_cons t<int>::type>::type, int const&>::value)); BOOST_STATIC_ASSERT((boost::is_same<add_const_ref<int&>::type, int&>::value)); BOOST_STATIC_ASSERT((boost::is_same<add_const_ref<int>::type, int const&>::value)); return 0; } Thanks for the input, Bruce > Philippe > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Re: C++ Template Metaprogramming - Exercise 2-0
by Lemings, Eric B. (Contr) 11 Jan '05

11 Jan '05

Dave Abrahams wrote: > Actually there's a much more concise solution using the type traits > library. That is, after all, the focus of the chapter. I believe that would be: template <typename T> struct add_const_ref { typedef add_const<add_ref<T>::type>::type type; }; Correct me if I'm wrong. Eric.

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