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

[boost::wave] MSVC 8 warning
by Ovanes Markarian 27 Mar '07

27 Mar '07

Hello, I would like to address this issue to boost::wave authors. First of all great lib! Many thanks! During the compilation with MSVC8 Express Edition I get a warning: c:\boost\include\boost-1_33_1\boost\wave\cpp_context.hpp(112) : warning C4355: 'this' : used in base member initializer list c:\boost\include\boost-1_33_1\boost\wave\cpp_context.hpp(106) : while compiling class template member function 'boost::wave::context<IteratorT,LexIteratorT>::context(const std::_String_iterator<_Elem,_Traits,_Alloc> &,const std::_String_iterator<_Elem,_Traits,_Alloc> &,const char *,const TraceT &)' with [ IteratorT=token_groups::str_iter_type, LexIteratorT=token_groups::lex_iter_type, _Elem=char, _Traits=std::char_traits<char>, _Alloc=std::allocator<char>, TraceT=boost::wave::context_policies::default_preprocessing_hooks ] My typedefs look like: typedef wave::cpplexer::lex_token<> token_type; typedef wave::cpplexer::lex_iterator<token_type> lex_iter_type; typedef std::string::iterator str_iter_type; typedef wave::context<str_iter_type, lex_iter_type> context_type; typedef context_type::iterator_type ctx_iter_type; Is there any chance that this warning will be suppressed in the next release, since it is a little bit annoying. I can't do anything about it as a user of wave and I also try to follow the rule to compile clean without warnings. Many thanks and With Kind Regards, Ovanes Markarian

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BOOST: Any planned release?
by dhruva 27 Mar '07

27 Mar '07

Hi, I am particularly looking for the boost::interprocess package. Is there any plan for a release in the near future? Has someone been using this in their production environment now. I have a real need and am evaluating if it is complete enough (with not too many changes planned) for me to replace the existing IPC mechanism used by us (McAfee). with best regards, dhruva -- Dhruva Krishnamurthy Contents reflect my personal views only!

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[serialization] custom xml archive and dynamic linking (VC 8.0)
by Sergey Skorniakov 27 Mar '07

27 Mar '07

Hello. I have tried to inherit my custom archive from xml_iarchive_impl and found no way to do it if macro BOOST_SERIALIZATION_DYN_LINK is defined. May be anybody already do that and can suggest me how?

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Re: [Boost-users] [test] detect_memory_leak option in msvc 8
by KLINIK Markus SDI2-G (AREVA NP GmbH) 27 Mar '07

27 Mar '07

> I am trying to get the --detect_memory_leak=1 option to detect a > memory leak in my code. Hi! In MSVC 7.0 the memory leak detection is somewhat primitive (I don't know about MSVC 8). I'm using Boost.Test together with mpatrol and it works great! Here is the output of a test run: <mpatrol_output> top 4 unfreed memory entries in leak table: bytes count location -------- ------ -------- 400 1 d:\[snip]\unittests\test_config.cpp line 10 84 1 d:\[snip]\tcpstream\src\myenv.cc line 145 24 1 c:\src\boost_1_33_1\libs\thread\src\mutex.inl line 55 8 1 c:\src\boost_1_33_1\libs\thread\src\tss_hooks.cpp line 29 516 4 total </mpatrol_output> NB. The first memory leak is intentional, the second is a resource leak from cppadvio. It also detects the already discussed resource leaks in Boost.Treads :) I needed some try-and-error to find the correct versions of mpatrol, Boost.Test and the windows runtime library, but now that it works, it is incredibly useful. (/MDd, mpatrolmt.dll, libboost_unit_test_framework-vc7-mt-gd.lib) Just for comparison, here is the output of the MSVC 7.0 memory leak detection of the same code: <msvc_output> Detected memory leaks! Dumping objects -> {11225} normal block at 0x00F3AA60, 24 bytes long. Data: < > 18 EE 14 00 FF FF FF FF 00 00 00 00 00 00 00 00 {11224} normal block at 0x00F3BBB0, 8 bytes long. Data: <` > 60 AA F3 00 01 CD CD CD {201} normal block at 0x00F35F90, 400 bytes long. Data: < > CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD {147} normal block at 0x00F35880, 84 bytes long. Data: < =b > 10 3D 62 00 00 00 00 00 00 00 00 00 FF FF FF FF Object dump complete. </msvc_output> Best regards Markus Klinik

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Proper initialization of a boost::shared_ptr<> in a constructor
by Stephen Torri 27 Mar '07

27 Mar '07

I am attempting to hunt down why I am getting a segmentation fault from the boost::shared_ptr class. I know that it has to do with how I am managing my shared pointers. That is creating and using them in functions. I am reading the best practices web page and I have a question about the best way to initialize a shared_ptr. Normally I have a class like the following: class A { public: typedef boost::shared_ptr<A> ptr_t; A ( int input_value ) : value ( input_value ) {} private: int value; }; Which I will use in another place: class A_User { public: A_User () : m_a_ptr ( new A() ) {} private: A::ptr_t m_a_ptr; }; Is this the correct way to initialize the A::ptr_t held in the A_User class in its constructor? Stephen

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[boost::function] problem with void type as argument type
by Seweryn Habdank-Wojewódzki 26 Mar '07

26 Mar '07

Hi! I have small piece of code and I do not know why it is not compiling - proper instantiation of function is not created. It means, why boost::function can not deduct types (code below). The problem is when type U is void. Can any one help me with it? Regards. template < typename T, typename U > void test ( boost::function<T(U)> & f ) { f(); } int f3() { std::cout << "f3(void)" << std::endl; return 3; } void f4() { std::cout << "f4(void)" << std::endl; return;// 4; } int main() { boost::function<int (void)> h = &f3; boost::function<void (void)> i = &f4; test (h); test (i); } -- |\/\/| Seweryn Habdank-Wojewódzki \/\/

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Re: [Boost-users] [bind] static array vs. pointer vector
by Daniel 26 Mar '07

26 Mar '07

> Date: Mon, 26 Mar 2007 11:24:08 -0400 > From: "Christian Henning" <chhenning(a)gmail.com> > Subject: [Boost-users] [bind] static array vs. pointer vector > To: boost-users(a)lists.boost.org > Message-ID: > <949801310703260824n31c76204pcd63bb686169e15c(a)mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi there, I have posted this question last Friday, already. But maybe > my example was too confusing. Here is a more simple example. > Basically, I don't see what the big difference is when using > boost::bind with a pointer vector ( std::vector<info*> ) and a static > array of info. > > Please consider the following code: > > #include <string> > #include <algorithm> > #include <functional> > #include <vector> > > #include <boost/bind.hpp> > > using namespace std; > using namespace boost; > > struct info > { > int a; > string s; > }; > > static info table[] = > { > { 16, "Hello" }, > { 18, "Moin" } > }; > > string& get_s( info* p ) > { > return p->s; > } > > int _tmain(int argc, _TCHAR* argv[]) > { > { > vector<info*> v; > find_if( v.begin(), v.end() > , bind( equal_to<string>() > , bind( &get_s, _1 ) > , "Moin" )); > } > > { > find_if( &table[0], &table[0] + 2 > , bind( equal_to<string>() > , bind( &get_s, _1 ) > , "Moin" )); > > } > } > > The second find_if wont complie using MSVC 7.1. The errors are: > > c:\boost\boost\bind.hpp(219) : error C2664: 'std::string &(info *)' : > cannot convert parameter 1 from 'info' to 'info *' [snip] > > Any ideas? > > Christian In 1st case, when you dereference vector<info*> iterator, you will get info* pointer. But in 2nd case, your iterator is info* pointer, so you get info object when you dereference it. This is also mentioned at beginning of error message - "cannot convert parameter 1 from 'info' to 'info *'". Therefore you should change your get_s() function to accept info (or info&), or your binding expression to convert info to info*. Daniel

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[bind] static array vs. pointer vector
by Christian Henning 26 Mar '07

26 Mar '07

Hi there, I have posted this question last Friday, already. But maybe my example was too confusing. Here is a more simple example. Basically, I don't see what the big difference is when using boost::bind with a pointer vector ( std::vector<info*> ) and a static array of info. Please consider the following code: #include <string> #include <algorithm> #include <functional> #include <vector> #include <boost/bind.hpp> using namespace std; using namespace boost; struct info { int a; string s; }; static info table[] = { { 16, "Hello" }, { 18, "Moin" } }; string& get_s( info* p ) { return p->s; } int _tmain(int argc, _TCHAR* argv[]) { { vector<info*> v; find_if( v.begin(), v.end() , bind( equal_to<string>() , bind( &get_s, _1 ) , "Moin" )); } { find_if( &table[0], &table[0] + 2 , bind( equal_to<string>() , bind( &get_s, _1 ) , "Moin" )); } } The second find_if wont complie using MSVC 7.1. The errors are: c:\boost\boost\bind.hpp(219) : error C2664: 'std::string &(info *)' : cannot convert parameter 1 from 'info' to 'info *' No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called c:\boost\boost\bind\bind_template.hpp(139) : see reference to function template instantiation 'R boost::_bi::list1<A1>::operator ()<boost::_bi::bind_t<R,F,L>::result_type,std::string&(__cdecl *)(info *),A>(boost::_bi::type<T>,F & ,A &,long)' being compiled with [ R=boost::_bi::bind_t<std::string &,std::string &(__cdecl *)(info *),boost::_bi::list1<boost::_bi::list_av_1<boost::arg<1>>::B1>>::result_type, A1=boost::_bi::list_av_1<boost::arg<1>>::B1, F=std::string &(__cdecl *)(info *), L=boost::_bi::list1<boost::_bi::list_av_1<boost::arg<1>>::B1>, A=const boost::_bi::list1<info &>, T=boost::_bi::bind_t<std::string &,std::string &(__cdecl *)(info *),boost::_bi::list1<boost::_bi::list_av_1<boost::arg<1>>::B1>>::result_type ] c:\boost\boost\bind.hpp(213) : see reference to function template instantiation 'boost::_bi::bind_t<R,F,L>::result_type boost::_bi::bind_t<R,F,L>::eval<const boost::_bi::list1<A1>>(A &)' being compiled with [ R=std::string &, F=std::string &(__cdecl *)(info *), L=boost::_bi::list1<boost::_bi::list_av_1<boost::arg<1>>::B1>, A1=info &, A=const boost::_bi::list1<info &> ] [snip] Any ideas? Christian

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[fusion] Stateful unary functor for for_each loop
by Christian Henning 26 Mar '07

26 Mar '07

Hi there, is it possible to have a stateful functor object when using fusion::for_each() loop. I would like to to the following: #include <vector> #include <boost/mpl/assert.hpp> #include <boost/mpl/equal.hpp> #include <boost/mpl/list.hpp> #include <boost/mpl/transform.hpp> #include <boost/fusion/algorithm/transformation/transform.hpp> #include <boost/fusion/algorithm/iteration/for_each.hpp> #include <boost/fusion/sequence/adapted/mpl.hpp> #include <boost/fusion/sequence/container.hpp> #include <boost/fusion/sequence/conversion/as_list.hpp> using namespace std; using namespace boost; struct A { void print() { cout << "A" << endl; }}; struct B { void print() { cout << "B" << endl; }}; struct C { void print() { cout << "C" << endl; }}; std::vector<A> find_all( A ) { return std::vector<A>(12); } std::vector<B> find_all( B ) { return std::vector<B>(12); } std::vector<C> find_all( C ) { return std::vector<C>(12); } typedef mpl::list< A, B, C > _types_; template <typename T> struct add_vector { typedef std::vector<T> type; }; struct find_all_ { template< class T > void operator()( T& t ) const { typedef typename T::value_type type; type v; t = find_all( v ); } }; struct check_size { check_size() : _init( false ), _size( 0 ) {} template< class T > void operator()( T& t ) { if( !_init ) { _size = t.size(); _init = true; return; } if( _size != t.size() ) { throw runtime_error( "vectors don't match up." ); } } private: bool _init; size_t _size; }; struct print { template< class T > void operator()( T& vec ) const { vec[0].print(); } }; int main() { typedef mpl::transform1< _types_, add_vector<mpl::_1> >::type _mpl_list_of_vectors_; typedef fusion::result_of::as_list<_mpl_list_of_vectors_>::type _fusion_list_of_vectors_; _fusion_list_of_vectors_ vectors; fusion::for_each( vectors, find_all_() ); fusion::for_each( vectors, check_size() ); return 0; } Unfortunately it wont compile. The error messages are: c:\boost\boost\fusion\algorithm\iteration\detail\for_each.hpp(28) : error C3848: expression having type 'const check_size' would lose some const-volatile qualifiers in order to call 'void check_size::operator ()<T>(T &)' with [ T=boost::fusion::extension::deref_impl<boost::fusion::cons_iterator_tag>::apply<boost::fusion::cons_iterator<_fusion_list_of_vectors_>>::value_type ] c:\boost\boost\fusion\algorithm\iteration\for_each.hpp(37) : see reference to function template instantiation 'void boost::fusion::detail::for_each<boost::fusion::extension::begin_impl<boost::fusion::cons_tag>::apply<Sequence>::type,boost::fusion::extension::end_impl<boost::fusion::cons_tag>::apply<Sequence>::type,F>(const First &,const Last &,const F &,boost::mpl::false_)' being compiled with [ Sequence=_fusion_list_of_vectors_, F=check_size, First=boost::fusion::extension::begin_impl<boost::fusion::cons_tag>::apply<_fusion_list_of_vectors_>::type, Last=boost::fusion::extension::end_impl<boost::fusion::cons_tag>::apply<_fusion_list_of_vectors_>::type ] test.cpp(100) : see reference to function template instantiation 'void boost::fusion::for_each<_fusion_list_of_vectors_,check_size>(Sequence &,const F &)' being compiled with [ Sequence=_fusion_list_of_vectors_, F=check_size ] Any ideas? Christian

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Re: [Boost-users] [Serialization] issue withportable_binary_oarchive
by Pfligersdorffer, Christian 26 Mar '07

26 Mar '07

Dear Robert, > -----Original Message----- > From: boost-users-bounces(a)lists.boost.org > [mailto:boost-users-bounces@lists.boost.org]On Behalf Of Robert Ramey > Sent: Friday, March 16, 2007 9:49 PM > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] [Serialization] issue > withportable_binary_oarchive > > > Pfligersdorffer, Christian wrote: > > > 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? > > I've made some a few changes. I'll check them in to the HEAD before > tomorrow. I will have a look at that. > a) I made a small change to binary_?archvive which was losing > a "const" along the line and frustrating a template match > > b) I made a change in portable_binary_?archive to fix an > error whereby the sign bit was changed on certain > negative numbers. > > > Did you also add code to treat floating point types? > > Nope - that's an excercise for the user. > Notes on the current implementation: > > a) It presumes a two's complement computer so its not > "truely" portable. OK, I would not use it on some very fancy cpus then. ppc and x86 should probably work and that's what counts with me. > b) It doesn't include floating point. I think this would be more > effort than first meets the eye. At least one attractive proposal on > how to effectively do this was suggested. > c) Its not all that efficient on big endien machines. I think > a better version would write the data out in native mode > with flags in the header indicating how it was written. Then > the endian fix up would occur when it was moved from > one machine to another. I would like to switch to big endian representation to ensure maximum speed on the embedded system. This should easily be possible by changing the #ifdef BOOST_LITTLE_ENDIAN sections into #ifndef, or? ... > d) It focuses more on reducing archive size. So some > a 64 bit value of 0 is written as one byte. This is probably > a good choice for most. But it costs time in sign extending > etc. > > Robert Ramey By the way: did you solve the destruction issue when deleting an archive through the polymorphic interface? I sent you an email about that (a couple of months ago) and you answered you'd have a look at it. Regards, -- DI Christian Pfligersdorffer Software Engineering EOS GmbH

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