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MPL design question
by Jesse Perla 11 Mar '09

11 Mar '09

I have a class that is getting a huge number of template parameters (mostly a bunch of size_t used for vector sizes). They have a natural organization into groups, but almost all of them have a default as 0. How do you suggest that I design the template parameter for this? Is there any way to use some kind of associative container so I could look these up by "name" and default to 0 if they aren't there? I can't see how to use mpl::map to do this kind of stuff. Simplified Pseudocode: -------------------- What I have: template<std::size_t IndividualSize = 0, std::size_t AggregateSize> //Many others class my_problem{...}; What I want: template<class StateSizes> class MyProblem{...} Called something like: typedef my_problem<map<AggregateSize, 2> > my_problem_type; where AggregateSize is an enum, placeholder struct, etc. And in this case I would default IndividualSize to 0. -Jesse

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Re: [Boost-users] [wave] assertion failed - multithread issue?
by Ein Held 10 Mar '09

10 Mar '09

Hello Hartmut Using multiple threads, wave crashes randomly after a few seconds of running. The crash is actually an assert in test.exe!std::list<boost::wave::cpplexer::lex_token<boost::wave::util::file_position<boost::wave::util::flex_string<char,std::char_traits<char>,std::allocator<char>,boost::wave::util::CowString<boost::wave::util::AllocatorStringStorage<char,std::allocator<char> >,char *> > > >,boost::fast_pool_allocator<boost::wave::cpplexer::lex_token<boost::wave::util::file_position<boost::wave::util::flex_string<char,std::char_traits<char>,std::allocator<char>,boost::wave::util::CowString<boost::wave::util::AllocatorStringStorage<char,std::allocator<char> >,char *> > > >,boost::default_user_allocator_new_delete,boost::details::pool::win32_mutex,32> >::_Const_iterator<1>::operator*() Line 218 + 0x17 bytes C++ indicating that the iterator is not dereferencable. I am using an VC 9 x86 debug build on Vista x64. Here's the code: #include <fstream> #include <string> //Wave does not like the new interface :( //#define BOOST_FILESYSTEM_NO_DEPRECATED #include <boost/thread.hpp> #include <boost/wave.hpp> #include <boost/wave/cpplexer/cpp_lex_token.hpp> #include <boost/wave/cpplexer/cpp_lex_iterator.hpp> std::string file; const char* file_name="C:\\Program Files (x86)\\Microsoft SDKs\\Windows\\v5.0\\Include\\Windows.h"; void test() { for(;;) { typedef boost::wave::cpplexer::lex_token<> token_type; typedef boost::wave::cpplexer::lex_iterator<token_type> lex_iterator_type; typedef boost::wave::context<std::string::iterator, lex_iterator_type> context_type; context_type ctx (file.begin(), file.end(), file_name); ctx.set_language(static_cast<boost::wave::language_support>(boost::wave::support_cpp|boost::wave::support_option_variadics|boost::wave::support_option_include_guard_detection)); ctx.add_sysinclude_path("C:\\Program Files (x86)\\Microsoft SDKs\\Windows\\v5.0\\Include\\"); ctx.add_sysinclude_path("C:\\Program Files (x86)\\Microsoft Visual Studio 9.0\\VC\\include\\"); ctx.add_macro_definition("_CPPRTTI",true); ctx.add_macro_definition("_CPPUNWIND",true); ctx.add_macro_definition("_MT",true); ctx.add_macro_definition("_MSC_VER=1600",true); ctx.add_macro_definition("_M_IX86=600",true); ctx.add_macro_definition("_WIN32=600",true); context_type::iterator_type first = ctx.begin(); context_type::iterator_type last = ctx.end(); while (first != last) { ++first; } } } int main() { std::ifstream instream(file_name); file = std::string(std::istreambuf_iterator<char>(instream.rdbuf()),std::istreambuf_iterator<char>()); instream.close(); for(int i=0;i<10;++i) { boost::thread t(test); } test(); } Thank you

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boost/math/special_functions/legendre.hpp causing compile errors in other headers
by Jeremy Conlin 10 Mar '09

10 Mar '09

I recently started using the Boost Math libraries because I need legendre polynomials. However I cam across a problem I was hoping someone on this list could help me with. My personal code compiles fine with no problems. When I add the line #include "boost/math/special_functions/legendre.hpp" then I get compiler errors attributed to one of my header files. Specifically I get: my_header.hh:109 error: ISO C++ forbids declaration of ‘tuple’ with no type As I mentioned before, I don't believe the problem is in my header file because it compiles just fine without the legendre.hpp file. Has anyone seen this problem before? Do you know how to fix it? I am running gcc 4.2.1 on Mac OS X 10.5.6. Thanks, Jeremy

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[mpl] Trivial metafunctions and placeholders don't mix ?
by jean-louis.a.leroy＠fortis.com 10 Mar '09

10 Mar '09

Hello. I'm trying to use a pair<> to pass values inside a fold<> : template<typename Seq> struct remove_duplicates // even if not consecutive; also keep order { typedef typename mpl::second< mpl::fold< Seq, mpl::pair< mpl::set<>, mpl::vector<> >, typedef typename mpl::if_< mpl::has_key<mpl::first<mpl::_1>, mpl::_2>, mpl::_1, mpl::pair< typename mpl::insert< mpl::first<mpl::_1>, void, mpl::_2 >::type, // insert mpl::push_back< mpl::second<mpl::_1>, _2 >::type > // pair > >::type > type; }; It looks like first<> and second<> don't work on placeholders. My compiler - Visual Studio 2008 - complains that "'first' : is not a member of 'boost::mpl::arg<1>". When I look at the definition of first<> I see a "BOOST_MPL_AUX_LAMBDA_SUPPORT(1,first,(P))" that should take care of placeholders I guess. But when I look at the definition of the macro, alas : #if !defined(BOOST_MPL_CFG_NO_FULL_LAMBDA_SUPPORT) # define BOOST_MPL_AUX_LAMBDA_SUPPORT_SPEC(i, name, params) /**/ # define BOOST_MPL_AUX_LAMBDA_SUPPORT(i,name,params) /**/ What's the story here? My compiler is not good enough? Could be... While we're at it, should I put a BOOST_MPL_AUX_LAMBDA_SUPPORT(1,remove_duplicates,(P)) at the bottom of remove_duplicates<> ? Would it make my metafunction work with lambda placeholders? Thanks, Jean-Louis Leroy = = = = = = = = = = = = = = = = = = = = = = = = = Fortis disclaimer : http://www.fortis.be/legal/disclaimer.htm Privacy policy related to banking activities of Fortis: http://www.fortis.be/legal/privacy_policy.htm = = = = = = = = = = = = = = = = = = = = = = = = =

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Trouble using boost::edge_range in Boost Graph library
by Artyom 10 Mar '09

10 Mar '09

Hi all, I am having trouble getting this function to work. I am using 'multisetS' for OutEdgeProperty as instructed in the documentation, however, my code refuses to compile with the following errors: http://rafb.net/p/LgT89332.html I am using Visual Studio 8.0 SP1 under Windows Vista x64. Regards, Artyom

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[program_options] Getting access to the remaining argv
by Ruediger Berlich 10 Mar '09

10 Mar '09

Hi there, I have a program ("A") that calls other, external programs ("B"). A can get a number of command line options, which are parsed with the help of the program_options library. B may also accept options (which are possibly defined by other people and not known to me in advance). Thus I want to pass all those options that are not known to A on to B, in the hope that they are needed for that program. Is there a way to retrieve the remaining argv string, with all options "known" to A removed ? Or should I better invent a flag of the following kind for A --external-options="-a 1 -b 2 -c 3" whose value is passed on to the external program ? Thanks and Best Regards, Ruediger

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BGL Graph support for named vertices in adjacency_list documentation?
by ljw＠onet.eu 10 Mar '09

10 Mar '09

Is there any documentation available for the support for named vertices in adjacency_list introduced with version 1.38 and announced in the release notes? Regards Łukasz Wojakowski

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[asio] Synchronous/Asynchronous pattern
by Rutger ter Borg 10 Mar '09

10 Mar '09

In an application we would like to support synchronous operations in the application layer, whereas operations below it are done with asynchronous operations. Callback handlers are not appropriate in this case, To make the example more clear, suppose you have a remote_vector which you would like to iterate through, remote_vector a(10); for( int i=0; i<10; ++i ) { std::cout << a[i] << std::endl; } here, a[i] will cause messages to be sent to retrieve the actual vector data before printing it. The network layer is hidden from the user. What is the best way to "emulate" synchronous behaviour with asio? The thread running this iteration should not block, but do other work (at the io_service?) until the requested results are received. Many thanks, Kind regards, Rutger ter Borg

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condition_variable::timed_wait doesn't wait
by Daniele Barzotti 10 Mar '09

10 Mar '09

Hi! I'm trying to use condition_variable::timed_wait without success. Using the following code, the timed_wait returns immediatly also if Receive() is never called. Where I wrong? void Receive() { boost::lock_guard<boost::mutex> lock(_mut); //... code ...// _data_ready = true; // Notify and unlock the mutex _cond.notify_one(); } bool Send() { boost::unique_lock<boost::mutex> lock(_mut); boost::xtime xt; xtime_get(&xt, boost::TIME_UTC); xt.sec += 5; _data_ready = false; //... send data ...// //wait for an answer.. bool ready = _cond.timed_wait(lock, xt, boost::lambda::var(_data_ready)); return ready; } I've also tried to use: ptime t = second_clock::universal_time(); ptime timeout = t + milliseconds(cmd_timeout); bool ready = _cond.timed_wait(lock, timeout, boost::lambda::var(_data_ready)); but with the same effect. Thanks, Daniele.

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Re: [Boost-users] Pointer serialization and deserialization
by niranjan bangera 10 Mar '09

10 Mar '09

Robert, Yes the pointer is been initialized by NULL in the constructor of the class of that pointer. Thanks, Niranjan Do you know for a fact that the *pointer* has been initialized? Robert Ramey "niranjan bangera" <niranjannina@...<http://www.nabble.com/user/SendEmail.jtp?type=post&post=22416132&i=0>> wrote in message news:50a2f6f20903090457n37c0bfb2n3eec9d716a56c84c@...<news://50a2f6f20903090457n37c0bfb2n3eec9d716a56c84c@mail.gmail.com/> ... Hi all, Boost:1.38.0 compiler:gcc4.1.1 I am trying to serialize *and* deserialize a *pointer* to the class, but ended with the segmentation fault, Is that the null *pointer* *serialization * gives the segmentation fault?. I read in document that, library will maintain the Null *pointer*. if not how can i serialize? ,any docs or related refference is a;so acceptable. Thanks in advance.... one more thing: what -1 in archive(text_archive) indicates? Example ------------ #include <fstream> #include "boost/archive/text_iarchive.hpp" #include "boost/archive/text_oarchive.hpp" #include "boost/*serialization*/access.hpp" #include "boost/*serialization*/assume_abstract.hpp" class Dkpt { public: friend class boost::*serialization*::access; template<class Archive> void serialize(Archive & ar, const unsigned int file_version) { (void) file_version; ar & data_; ar & b_i; ar & f_er; ar & pa_er; ar & ct_c; } private: uint8_t data_; bool b_i; bool f_er; bool pa_er; bool ct_c; }; ---- class RB : public RM { public: virtual void checkpoint_save(boost::archive::text_oarchive & oa) { oa & dr; } virtual void checkpoint_retrive(boost::archive::text_iarchive & ia) { ia & dr; } private: Dkpt* dr; ;} Thanks. Niranjan

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