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boost 1.40 beta libs, no longer include compiler version/boost version ?
by Avi Bahra 20 Aug '09

20 Aug '09

When building boost 1.40 the libraries produced don't include compiler version or boost version any more ? i.e boost 1.38 bjam --build-dir=./tmpBuildDir toolset=gcc stage link=static --with-date_time libboost_date_time-gcc42-mt.a -> libboost_date_time-gcc42-mt-1_38.a with boost 1.40 beta bjam --build-dir=./tmpBuildDir toolset=gcc stage link=static --with-date_time libboost_date_time.a Is this expected or a bug ? Best regards, Ta, Avi

4 4

[Help] crash in boost::asio::detail::time_queue
by zong jinliang 20 Aug '09

20 Aug '09

My code use boost::asio and log4cplus. There is any memory write error(as follow) which is detected by valgrind. And i can't fix the question. I have used log4cplus for a long time, and detect my program in valgrind in time, havn't found that there is memory error in log4cplus. This is the first time to use boost::asio. Anybody meet crash in boost::asio::detail::time_queue? ==4743== ==4743== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 18 from 1) ==4743== ==4743== 1 errors in context 1 of 2: ==4743== Invalid write of size 4 ==4743== at 0x805BD6B: boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::remove_timer(boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::timer_base*) (timer_queue.hpp:401) ==4743== by 0x805C1D2: boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::dispatch_timers() (timer_queue.hpp:119) ==4743== by 0x80619C9: boost::asio::detail::epoll_reactor<false>::run(bool) (epoll_reactor.hpp:553) ==4743== by 0x8061D4F: boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> >::do_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&, boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> >::idle_thread_info*, boost::system::error_code&) (task_io_service.hpp:260) ==4743== by 0x8061F49: boost::asio::detail::task_io_service<boost::asio::detail::epoll_reactor<false> >::run(boost::system::error_code&) (task_io_service.hpp:103) ==4743== by 0x8061FFD: boost::asio::io_service::run() (io_service.ipp:58) ==4743== by 0x8050392: CohService::start() (CohService.cpp:29) ==4743== by 0x8064101: boost::_mfi::mf0<void, CohService>::operator()(CohService*) const (mem_fn_template.hpp:49) ==4743== by 0x8064151: void boost::_bi::list1<boost::_bi::value<CohService*> >::operator()<boost::_mfi::mf0<void, CohService>, boost::_bi::list0>(boost::_bi::type<void>, boost::_mfi::mf0<void, CohService>&, boost::_bi::list0&, int) (bind.hpp:246) ==4743== by 0x8064194: boost::_bi::bind_t<void, boost::_mfi::mf0<void, CohService>, boost::_bi::list1<boost::_bi::value<CohService*> > >::operator()() (bind_template.hpp:20) ==4743== by 0x80641AD: boost::detail::thread_data<boost::_bi::bind_t<void, boost::_mfi::mf0<void, CohService>, boost::_bi::list1<boost::_bi::value<CohService*> > > >::run() (thread.hpp:56) ==4743== by 0x80B0F4C: thread_proxy (in /home/zjl/test/trunk/cohcommand/test) ==4743== Address 0x4f2d2f8 is 32 bytes inside a block of size 33 free'd ==4743== at 0x40052BC: operator delete(void*) (vg_replace_malloc.c:342) ==4743== by 0x57A813C: std::string::_Rep::_M_destroy(std::allocator<char> const&) (in /usr/lib/libstdc++.so.6.0.8) ==4743== by 0x57A9F64: std::string::_M_mutate(unsigned int, unsigned int, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==4743== by 0x57A9FB9: std::string::_M_replace_safe(unsigned int, unsigned int, char const*, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==4743== by 0x80AF5B5: std::string& std::string::_M_replace_dispatch<__gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > > >(__gnu_cxx::__normal_iterator<char*, std::string>, __gnu_cxx::__normal_iterator<char*, std::string>, __gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > >, __false_type) (basic_string.tcc:643) ==4743== by 0x80AEF19: log4cplus::helpers::Time::getFormattedTime(std::string const&, bool) const (basic_string.h:1374) ==4743== by 0x80A236D: log4cplus::pattern::DatePatternConverter::convert(log4cplus::spi::InternalLoggingEvent const&) (patternlayout.cxx:385) ==4743== by 0x80A4AC7: log4cplus::pattern::PatternConverter::formatAndAppend(std::ostream&, log4cplus::spi::InternalLoggingEvent const&) (patternlayout.cxx:234) ==4743== by 0x80A4E57: log4cplus::PatternLayout::formatAndAppend(std::ostream&, log4cplus::spi::InternalLoggingEvent const&) (patternlayout.cxx:742) ==4743== by 0x8093078: log4cplus::RollingFileAppender::append(log4cplus::spi::InternalLoggingEvent const&) (fileappender.cxx:315) ==4743== by 0x8083F72: log4cplus::Appender::doAppend(log4cplus::spi::InternalLoggingEvent const&) (appender.cxx:207) ==4743== by 0x80826BD: log4cplus::helpers::AppenderAttachableImpl::appendLoopOnAppenders(log4cplus::spi::InternalLoggingEvent const&) const (appenderattachableimpl.cxx:159) ==4743== ==4743== 1 errors in context 2 of 2: ==4743== Thread 1: ==4743== Invalid write of size 4 ==4743== at 0x807CB59: bool boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >::enqueue_timer<boost::asio::detail::deadline_timer_service<boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::detail::epoll_reactor<false> >::wait_handler<boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> > > >(boost::posix_time::ptime const&, boost::asio::detail::deadline_timer_service<boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::detail::epoll_reactor<false> >::wait_handler<boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> > >, void*) (timer_queue.hpp:80) ==4743== by 0x807CCC6: void boost::asio::detail::epoll_reactor<false>::schedule_timer<boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::detail::deadline_timer_service<boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::detail::epoll_reactor<false> >::wait_handler<boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> > > >(boost::asio::detail::timer_queue<boost::asio::time_traits<boost::posix_time::ptime> >&, boost::asio::time_traits<boost::posix_time::ptime>::time_type const&, boost::asio::detail::deadline_timer_service<boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::detail::epoll_reactor<false> >::wait_handler<boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> > >, void*) (epoll_reactor.hpp:414) ==4743== by 0x807CD9F: void boost::asio::detail::deadline_timer_service<boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::detail::epoll_reactor<false> >::async_wait<boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> > >(boost::asio::detail::deadline_timer_service<boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::detail::epoll_reactor<false> >::implementation_type&, boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> >) (deadline_timer_service.hpp:185) ==4743== by 0x807CE01: void boost::asio::deadline_timer_service<boost::posix_time::ptime, boost::asio::time_traits<boost::posix_time::ptime> >::async_wait<boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> > >(boost::asio::detail::deadline_timer_service<boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::detail::epoll_reactor<false> >::implementation_type&, boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> >) (deadline_timer_service.hpp:157) ==4743== by 0x807CE35: void boost::asio::basic_deadline_timer<boost::posix_time::ptime, boost::asio::time_traits<boost::posix_time::ptime>, boost::asio::deadline_timer_service<boost::posix_time::ptime, boost::asio::time_traits<boost::posix_time::ptime> > >::async_wait<boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> > >(boost::_bi::bind_t<void, boost::_mfi::mf1<void, CohClientConn, boost::system::error_code const&>, boost::_bi::list2<boost::_bi::value<CohClientConn*>, boost::arg<1> (*)()> >) (basic_deadline_timer.hpp:374) ==4743== by 0x80720B3: CohClientConn::CohClientConn(ICohCommand*, boost::asio::io_service&, std::string const&, unsigned int, std::string const&, int, int) (CohClientConn.cpp:28) ==4743== by 0x80500D2: CohService::start_conn(ICohCommand*, std::string const&, unsigned int, std::string const&) (CohService.cpp:34) ==4743== by 0x8064C3A: ICohCommand::DoRequest(std::string const&, unsigned int, std::string const&) (ICohCommand.cpp:5) ==4743== by 0x804C9C8: GetConfig::Run() (GetConfig.cpp:18) ==4743== by 0x804D0E5: ICohAgent::DoGetConfig(void*, std::string const&, std::string const&, std::string const&, std::string const&, std::string const&, std::string const&) (ICohAgent.cpp:7) ==4743== by 0x804D64D: main (test.cpp:23) ==4743== Address 0x4f2d2f8 is 32 bytes inside a block of size 33 free'd ==4743== at 0x40052BC: operator delete(void*) (vg_replace_malloc.c:342) ==4743== by 0x57A813C: std::string::_Rep::_M_destroy(std::allocator<char> const&) (in /usr/lib/libstdc++.so.6.0.8) ==4743== by 0x57A9F64: std::string::_M_mutate(unsigned int, unsigned int, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==4743== by 0x57A9FB9: std::string::_M_replace_safe(unsigned int, unsigned int, char const*, unsigned int) (in /usr/lib/libstdc++.so.6.0.8) ==4743== by 0x80AF5B5: std::string& std::string::_M_replace_dispatch<__gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > > >(__gnu_cxx::__normal_iterator<char*, std::string>, __gnu_cxx::__normal_iterator<char*, std::string>, __gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > >, __false_type) (basic_string.tcc:643) ==4743== by 0x80AEF19: log4cplus::helpers::Time::getFormattedTime(std::string const&, bool) const (basic_string.h:1374) ==4743== by 0x80A236D: log4cplus::pattern::DatePatternConverter::convert(log4cplus::spi::InternalLoggingEvent const&) (patternlayout.cxx:385) ==4743== by 0x80A4AC7: log4cplus::pattern::PatternConverter::formatAndAppend(std::ostream&, log4cplus::spi::InternalLoggingEvent const&) (patternlayout.cxx:234) ==4743== by 0x80A4E57: log4cplus::PatternLayout::formatAndAppend(std::ostream&, log4cplus::spi::InternalLoggingEvent const&) (patternlayout.cxx:742) ==4743== by 0x8093078: log4cplus::RollingFileAppender::append(log4cplus::spi::InternalLoggingEvent const&) (fileappender.cxx:315) ==4743== by 0x8083F72: log4cplus::Appender::doAppend(log4cplus::spi::InternalLoggingEvent const&) (appender.cxx:207) ==4743== by 0x80826BD: log4cplus::helpers::AppenderAttachableImpl::appendLoopOnAppenders(log4cplus::spi::InternalLoggingEvent const&) const (appenderattachableimpl.cxx:159)

1 1

[fusion] "real" return types
by Stefan Strasser 19 Aug '09

19 Aug '09

I have a problem with boost.fusion I can't figure out from the documentation. consider the following example: template<class Vector> ? function(Vector vec){ return fusion::push_back(vec,123); } what is the return type ? the return type is supposed to be a random access sequence, so result_of::push_back<Vector,int>::type is not an option, because push_back only returns a forward sequence. so I have to construct a new vector from the view that push_back returns. if Vector was vector<char,short> I need to find the type vector<char,short,int>, preferrably without an own MPL algorithm since this is only a simple test case, the real return type is much more complex and based on more than one transformation function. thank you

2 1

[python] raw pointer data members
by Igor Mikushkin 19 Aug '09

19 Aug '09

Hello Boosters, I'm trying to use Boost Python that way: template<class Key> struct Node { Node(Key key): key(key) {} Node* parent; Node* left; Node* right; Key key; }; ..... BOOST_PYTHON_MODULE(tree) { class_<Node>("Node", init<int>()) .def_readwrite("parent", &Node::parent) .def_readwrite("left", &Node::left) .def_readwrite("right", &Node::right) .def_readwrite("key", &Node::key); }; But then I can't use parent, left and right properties in Python code. Is there a way to convert these raw pointers to common object reference in Python? Thanks in advance, Igor

2 2

[Pool] Thoughts about new pool class
by Roman Shmelev 19 Aug '09

19 Aug '09

Hi! I've got an idea about memory allocation situation. 1) User needs to allocate memory chunks of random length during the program run (or significant part of that run); 2) User will need to free all chunks together, not some of them. I guess, it is rather simple for programmer to write such class-allocator (I've written one). But I guess I'm not professional enough to write class that could be included to Boost. More, does anybody need one? Does anybody want to handle such task? so curious..

1 0

Re: [Boost-users] [Proto] Building a mpl::vector from an expression
by christophe henry 19 Aug '09

19 Aug '09

Hi Eric, > You could use reverse_fold instead of reversing the whole list after the > transform. Or you could use reverse_fold_tree to get the vector and then > pop the attribute_ off the front. That's probably fastest and simplest. I must be doing something wrong (I suppose it has something to do with my second "when") because parsing: attributes_ << int() << bool() << string() With the above given grammar gives me a mpl::vector<string,bool,int>, which is normal, but if I simply and naively replace fold by reverse_fold, all I get is a mpl::vector<int>. Am I missing something obvious? Thanks, Christophe _________________________________________________________________ More than messages–check out the rest of the Windows Live™. http://www.microsoft.com/windows/windowslive/

2 1

Re: [Boost-users] boost 1.40 beta, serialization via base pointer crashes
by Avi Bahra 19 Aug '09

19 Aug '09

> Is the "latest AIX v10.1 compiler" the same as the IBM VaCPP used in the trunk tests? These > tests show that compiler failing a number of tests which use export. This has been traced >to the compiler optimizing out code not explicitly referred to. > >Robert Ramey I am not familiar with the trunk tests. However XL 10.1.0.3 AIX is the latest C++ compiler. This use vacpp as the bjam toolset argument. But internally I gather it uses xlC. When I ran the sample in the Totalview(debugger) it shows the following. Can't read type info for "basic_pointer_oserializer": Expecting mangled name, and didn't find one. Can't read type info for "basic_pointer_iserializer": Expecting mangled name, and didn't find one. Can't read type info for "singleton<boost__archive__detail__<unnamed>__guid_initializer<RepeatBase> >": Expecting ":", and didn't find one. Can't read type info for "singleton<boost__archive__detail__<unnamed>__guid_initializer<RepeatDerived> >": Expecting ":", and didn't find one. Can't read type info for "singleton_wrapper<boost__archive__detail__<unnamed>__guid_initializer<RepeatBase> >": Expecting ":", and didn't find one. Can't read type info for "singleton_wrapper<boost__archive__detail__<unnamed>__guid_initializer<RepeatDerived> >": Expecting ":", and didn't find one. Can't read type info for "error_info_container": Expecting mangled name, and didn't find one. Can't read type info for "init_guid<RepeatBase>": Expecting ":", and didn't find one. Can't read type info for "init_guid<RepeatDerived>": Expecting ":", and didn't find one. >From your reply your saying that this is a compiler bug Do you know if any defect report has been raised ? Is there any workaround that stops the compiler doing these optimisation. If not is there possibility of changing the serialization code ? Best regards, Ta, Avi

2 1

Compiling errors
by Leandro Santos de Lima 19 Aug '09

19 Aug '09

Hi, I'm trying to compile my program code using boost phoenix but I'm receiving this error messages: \boost/spirit/home/classic/utility/grammar_def.hpp(107) : error C2039: > 'nil_t' : is not a member of 'boost::phoenix' \boost/spirit/home/classic/utility/grammar_def.hpp(110) : error C2039: > 'nil_t' : is not a member of 'boost::phoenix' \boost/spirit/home/classic/utility/grammar_def.hpp(180) : error C2143: > syntax error : missing ';' before '<' I guess this errors are caused by some wrong define or include but I don't know how to fix it. Thanks, Leandro Lima

1 0

[boost-users][conversion] 1.34.1 upgrade to 1.39 lexical_cast
by Ryan McConnehey 19 Aug '09

19 Aug '09

I have code that converts, using lexical_cast, some numeric values to strings. When upgrading from boost 1.34.1 to 1.39 some of my float and double test values changed. For example the numeric value 1111.11 converts to the string value "1111.11" in boost 1.34.1. In boost 1.39 the numeric value 1111.11 converts to the string value "1111.1099999999999". I find it odd that some values give this long string representation but other values convert exactly (1222.22 for example). Can someone tell me what changed from 1.34.1 to 1.39. I'm pretty sure it has to be the underling code in boost since I used Microsoft Visual Studio 2005 IDE for building my project with both boost versions. The code I'm using is as follows: template <typename T> std::string convertValueToText(T const& value) const { return boost::lexical_cast<std::string>( value ); } Ryan

2 4

Re: [Boost-users] [Proto] Building a mpl::vector from an expression
by christophe henry 19 Aug '09

19 Aug '09

"Eric Niebler" schrieb im Newsbeitrag news:<4A8BB56F.7050706(a)boostpro.com>... > Steven Watanabe wrote: > > christophe henry wrote: > >> I am trying to build a mpl::vector from an expression like > >> > >> (string(),ClassA(),ClassB()) > >> > >> To get a mpl::vector > >> > >> > >> Is there a way to do this or I should give up the idea? > > > > Does fold_tree help? > > It does. > *snip* Ah It see. Thanks a lot, I think I got the idea. I just have a concern with: template<class T> struct is_my : mpl::false_ {}; template<> struct is_my<std::string> : mpl::true_ {}; template<> struct is_my<ClassA> : mpl::true_ {}; template<> struct is_my<ClassB> : mpl::true_ {}; As it forces extra declarations which not everybody is willing to make. But based on the same fold idea I can allow something like: attributes_ << int() << std::map<int,int>() << bool() Where attributes_ is made a proto terminal<my_tag> with proto::extends and the following grammar (which I shamelessly stole from the doc): struct BuildAttributes : proto::or_< // Don't add the flag terminal to the list proto::when< proto::terminal< my_tag > , proto::_state > // Put all other terminals at the head of the // list that we're building in the "state" parameter , proto::when< proto::terminal<proto::_> , fusion::cons<proto::_value, proto::_state>(proto::_value, proto::_state) > // For left-shift operations, first fold the right // child to a list using the current state. Use // the result as the state parameter when folding // the left child to a list. , proto::when< proto::shift_left<BuildAttributes, BuildAttributes> , proto::fold< proto::_ , fusion::nil() , BuildAttributes>() > > {}; I then just have to invert the order again as it gets reversed (ok a few seconds more to compile...): boost::mpl::copy<typename boost::result_of<BuildAttributes(Attr)>::type,boost::mpl::front_inserter<boost::mpl::vector<> > >::type Correct? Thanks a lot, Christophe _________________________________________________________________ Drag n’ drop—Get easy photo sharing with Windows Live™ Photos. http://www.microsoft.com/windows/windowslive/products/photos.aspx

2 1

[Boost.Smart_ptr] global_reset (revamp) for shared_ptr
by Robbie Morrison 19 Aug '09

19 Aug '09

Hello Boost-Users CAVEAT The attached code "works" but has a major design flaw regarding pointer conversion safety -- one which can currently either be accepted (at your risk) or rectified by limiting usage to one-hop inheritance. In particular, statement [3] (see below) is processed without complaint in unsafe mode -- when it should ideally provoke a compile-time error. Indeed, providing a general type-safe solution is not without challenge (read: my knowledge of C++ has been exhausted). If interested, member function 'Common::reVamp' would be a good place to start. PROBLEM I recently needed a 'shared_ptr' that could be globally reset -- that is, any one of the owners of the controlled resource could unilaterally replace that resource for the benefit (perhaps) of everyone else. This has been named "global_reset" in previous postings -- but I have adopted the shorter word "revamp". Moreover, it would be useful if this newly conceived "assign_ptr" could mimic the behavior of 'shared_ptr', whilst simultaneously providing the additional functionality. In particular, implicit upcasting should be maintained. This lead me to quickly reject options like: shared_ptr<scoped_ptr<Resource> > ptrPtrResource; And instead try to implement something like: assign_ptr<T> py(new Y()); My environment is single-threaded and issues like CPU cycles and memory consumption are not significant. Of more importance to me was coding at a high level -- in part, because I imagined that any conforming solution could subsequently be refactored to improve on performance and safety. SOLUTION STRATEGY The proposed solution has parallels with the Observer pattern and relies on 'shared_ptr' to do most of the work. Notwithstanding the code is now considerably more involved than I had originally envisaged. The biggest challenge was getting a multi-step inheritance chain to play ball with the semantics and syntax. Consider, if you would: class A; // base class class B : public A; class C : public B; // and perhaps more assign_ptr<B> b(new C()); // C resource held by B pointer [1] assign_ptr<A> a = b; // resource now also held by A pointer a.revamp(new C()); // not so simple to implement [2] The statement marked [2] looks reasonable. But it offers my observer class a challenge -- namely the need to have available the type information present during statement [1] when re-assigning the replacement resource to 'b' during the 'revamp' call. In addition, the following statement should fail in some way -- ideally at compile-time: a.revamp(new A()); // okay for 'a', nonsensical for 'b' [3] The following member functions are offered, noting that the first two are already part of 'shared_ptr:' a.use_count() // number of owners in the pool a.unique() // true if use_count() == 1 a.revamp_count() // number of revamps a.original() // true if revamp_count() == 0 a.external_count() // number of owners outside the pool a.exclusive() // true if external_count() == 0 PRIOR DISCUSSIONS The problem itself is noted in the Boost documentation: Boost Libraries + Smart Pointers + shared_ptr class template + Smart Pointer Programming Techniques + Obtaining a shared_ptr from a raw pointer One significant thread on this topic can be found at: subject = shared_ptr and global reset date = Feb-2009 http://thread.gmane.org/gmane.comp.lib.boost.user/45032/focus=45034 CODE A single *.cc file is attached. This code was developed using: boost : 1.39.0 (built from source) compiler : GCC g++ 4.1.2 (2006) kernel : Ubuntu 6.10 Linux 2.6.17-12-generic hardware : 1.4GHz Intel Celeron M / 512MiB RAM DESIGN SUMMARY This section gives a brief outline of the design thinking I used. Note too that the code is also extensively documented. The point-of-entry is class template 'assign_ptr'. This holds its own controlled resource pointer, just like 'shared_ptr', but in this case, as a 'shared_ptr'. It also holds a 'shared_ptr' to a class 'Common' object (aka "Subject" under the Observer pattern). Class 'Common' manages a list of its 'Client's (aka "Observers") and, in doing so, defines the pool. The derived class template 'ClientImp' duly retains the type of its associated 'assign_ptr'. The various 'assign_ptr' member functions pass requests to the 'Common' object, which responds accordingly. Most of these member functions were declared above. Class 'Common', in turn, contains the management functions 'attach' and 'detach' and the interventionist function 'reVamp'. The remainder of the 'assign_ptr' implementation is aimed at providing a similar interface to 'shared_ptr'. Finally, everything is placed in namespace 'xeona'. LITERATURE Alexandrescu (2001, ch7, pp157-195) devotes a chapter to smart pointers and the underlying design trade-offs -- however "revamping" is not considered: Alexandrescu, Andrei. 2001. Modern C++ design : generic programming and design patterns applied. Addison-Wesley, Boston, USA. ISBN 0-201-70431-5. The notion of "revamping" is never far away in Meyers (1996 item29 pp183-213) reference counting example, but neither is it directly mentioned. Meyers, Scott. 1996. More effective C++ : 35 new ways to improve your programs and design. Addison-Wesley, Boston, USA. ISBN 0-201-63371-X. Some ideas regarding the use of Boost.Any came from the following book (which I found both instructional and nicely written): Karlsson, Bjoern. 2006. Beyond the C++ Standard Library : an introduction to Boost. Addison-Wesley, Upper Saddle River, New Jersey, USA. ISBN 0-321-13354-4. The following web article offered some insights on solutions: Becker, Thomas. 2007. On the tension between object-oriented and generic programming in C++ : and what type erasure can do about it. C++ Source. [http://www.artima.com/cppsource/type_erasure1.html] Finally, Dattatri (2002 pp487-496) provides an implementation of counted pointers and discusses the design issues in some depth. Dattatri, Kayshav. 2002. C++ : effective-object oriented software construction : concepts, principles, industrial strategies and practices -- Second edition. Prentice Hall PTR, Upper Saddle River, New Jersey, USA. ISBN 0-13-086769-1. ABOUT THE AUTHOR I am a PhD student writing a policy-oriented energy system simulation at the Institute for Energy Engineering (IET), Technical University of Berlin (TU-Berlin), Germany. I have never coded professionally, but consider myself reasonably competent in terms of scientific programming. --- I am happy to take comments, suggestions, and patches and will post an update in due course. Please note that I will be checking my email only infrequently over the next four weeks or so. best wishes to all Robbie Morrison --- PhD student -- policy-oriented energy system simulation Technical University of Berlin (TU-Berlin), Germany University email (redirected) : morrison(a)iet.tu-berlin.de Webmail (preferred) : robbie(a)actrix.co.nz [from IMAP client]

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boost::enable_if, did I get it wrong ?
by topoden 19 Aug '09

19 Aug '09

Hello, I'm trying to use boost::enable_if to customize function declaration for a particular set of template arguments. But instead of using SFINAE to remove incorrect declaration it produces error. See the example below to see better what I mean: #include <boost/utility.hpp> #include <boost/type_traits.hpp> template<class A, class B> struct BaseListener { typename boost::disable_if<boost::is_void< B >, void>::type void virtual process(A *, B *) = 0; typename boost::enable_if<boost::is_void< B >, void>::type void virtual process(A *) = 0; }; struct Request { }; struct Response { }; typedef BaseListener<Response, void> BaseResponseListener; typedef BaseListener<Request, BaseResponseListener> BaseRequestListener; struct RequestListener : public BaseRequestListener { void process(Request *, BaseResponseListener *) { } }; struct ResponseListener : public BaseResponseListener { void process(Request *) { } }; int main(int argc, char * argv[]) { RequestListener reqListener; ResponseListener resListener; return 0; } error message: error C2039: 'type' : is not a member of 'boost::enable_if<Cond,T>' 1> with 1> [ 1> Cond=boost::is_void<BaseResponseListener>, 1> T=void 1> ] 1> c:\!projects\temp\consoleeventhandler\consoleeventhandler.cpp(134) : see reference to class template instantiation 'BaseListener<A,B>' being compiled 1> with 1> [ 1> A=Request, 1> B=BaseResponseListener 1> ] -- View this message in context: http://www.nabble.com/boost%3A%3Aenable_if%2C-did-I-get-it-wrong---tp250279… Sent from the Boost - Users mailing list archive at Nabble.com.

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[Proto] Building a mpl::vector from an expression
by christophe henry 19 Aug '09

19 Aug '09

Hi, I am trying to build a mpl::vector from an expression like (string(),ClassA(),ClassB()) To get a mpl::vector<string,ClassA,ClassB> With string, ClassA and ClassB being not enough under control to protoify them with a proto::extends. I naively tried the following grammar struct BuildFlags : proto::or_< proto::when < proto::terminal<proto::_>, boost::mpl::vector<proto::_child>() >, proto::when < proto::comma<BuildFlags,BuildFlags >, boost::mpl::push_back< BuildFlags(proto::_left),proto::_right>() > > {}; Or some typeof variants of it, with no more success and I start wondering if I got on a rocky way leading me to unavoidable doom. Is there a way to do this or I should give up the idea? Thanks, Christophe _________________________________________________________________ Share your memories online with anyone you want. http://www.microsoft.com/middleeast/windows/windowslive/products/photos-sha…

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[bind] How do I....?
by Robert Jones 19 Aug '09

19 Aug '09

Use bind to call a free function on a vector of shared_ptrs? struct A { }; void f(const A&); std::vector<boost::shared_ptr<A> > v; for_each(v.begin(), v.end(), boost::bind(f, ???? ) ); what goes where ???? is? Thanks, Rob.

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[GRAPH]write_graphviz and setS edges
by Matthieu BOUSSARD 18 Aug '09

18 Aug '09

Hi, I'd like to use the simple write_graphviz function write_graphviz(std::cout,g); but since my graph doesn't allow multiple edges between two vertices, the graph type is defined by : typedef adjacency_list <listS,setS, directedS,...>Graph; but then I can't use the write_graphviz function anymore (compilation error). If I declare my graph with typedef adjacency_list <listS,vecS, directedS,...>Graph; it is fine, but have multiple edges... So my question is : is there a way to use write_graphviz with the setS edges representation ? Thank you, Matthieu

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[function] equivalent of std::binary_function
by alfC 18 Aug '09

18 Aug '09

Does Boost have the technology to define the equivalent of std::binary_function<double, double, double> eg something like boost::nary_function<double(double, double)> Note that I am not interested in storing any function pointer, so using boost::function<double(double, double)> would be a waste. But I want to use the nice syntax "<double(double,double)>" that boost::function uses, instead of "<double, double, double>". The objective is to inherit from this class and instead of class op : std::binary_function<double, double, double>{ ... } to have class op: nary_function<double(double, double)>{ ... } if possible. Thank you, Alfredo

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Linker error
by vikas chandra 18 Aug '09

18 Aug '09

Hi,I was using boost version 1.33.1 earlier. Recently I have downloaded the src file of boost_1.39. Built the regx library and replaced the old libs and header files in my project. But while linking it gives the error: "fatal error LNK1104: cannot open file 'libboost_regex-vc80-mt-sgd-1_33_1.lib'". I dont understand why it is still looking for old 1_33_1.lib. I tried to rebuild the project also but doesnt work. Can anyone help me out? -- Thank You. Regards, Vikas Chandra

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boost 1.40 beta, serialization via base pointer crashes
by Avi Bahra 18 Aug '09

18 Aug '09

The following example works on Linux/gcc but crashes on latest AIX v10.1 compiler #include <fstream> #include <assert.h> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/string.hpp> // no need to include <string> #include <boost/serialization/export.hpp> // explicit code for exports (place last) class RepeatBase { public: RepeatBase() {} virtual ~RepeatBase() {} virtual const std::string& name() const = 0; private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) {} }; class RepeatDerived : public RepeatBase { public: RepeatDerived( const std::string& name) : name_(name) {} RepeatDerived() {} virtual const std::string& name() const { return name_;} private: std::string name_; friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { // save/load base class information ar & boost::serialization::base_object<RepeatBase>(*this); ar & name_; } }; class Defs { public: Defs(const std::string& f) : fileName_(f), repeat_(new RepeatDerived(f)) {} Defs() : repeat_(NULL) {} ~Defs() { delete repeat_;} bool operator==(const Defs& rhs) const { return fileName_ == rhs.fileName_;} const std::string& fileName() const { return fileName_;} private: std::string fileName_; RepeatBase* repeat_; friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int /*version*/) { ar & fileName_; ar & repeat_; } }; BOOST_CLASS_EXPORT(RepeatBase); BOOST_CLASS_EXPORT(RepeatDerived); BOOST_SERIALIZATION_ASSUME_ABSTRACT(RepeatBase) int main() { // With this explicit cast we get a bit further, but still crashes on AIX // i.e crash on ar.save_pointer(vp, bpos); // // boost::serialization::void_cast_register<RepeatDerived, RepeatBase>(0,0); const Defs saveDefs("saveFile.txt"); { // Save the defs file std::ofstream ofs( saveDefs.fileName().c_str() ); boost::archive::text_oarchive oa( ofs ); oa << saveDefs; } { // Restore the defs file Defs loadDefs; std::ifstream ifs(saveDefs.fileName().c_str()); boost::archive::text_iarchive ia(ifs); ia >> loadDefs; assert( saveDefs == loadDefs ); } return 0; } //========================================================================================= This bug was present in boost 1.39 and is still broken in boost 1.40. The code above shows that base/derived relationship work on one compiler but is _competely_ broken another. Explicitly registering the base/derived relationship just moves the crash to a later point. template<class T> struct polymorphic { static void save( Archive &ar, T & t ){ ...... // convert pointer to more derived type. if this is thrown // it means that the base/derived relationship hasn't be registered vp = serialization::void_downcast( *true_type, *this_type, static_cast<const void *>(&t) ); if(NULL == vp){ boost::serialization::throw_exception( archive_exception(archive_exception::unregistered_cast) //< crash1 here ); } ..... ar.save_pointer(vp, bpos); //< crashe2 here after explicit base/derived registration I thought this bug had been fixed, so I am not sure if this is a regression ? Is there any way I can help, as this is show stopper bug for us. Best regards, Ta, Avi

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shared_ptr questions
by John Dlugosz 18 Aug '09

18 Aug '09

I'm looking at shared_ptr and weak_ptr as a TR1 standard approach. It is hard to follow the implementation, but I'm wondering about some specific issues. My set of classes (<http://www.dlugosz.com/Repertoire/refman/Classics/Smart%20Pointers%20Overvi…>), published over ten years ago, has similar features. My class "baro" is like your weak_pointer. I recall a threading issue where one thread is dropping the last owned reference at the same time another thread is realizing a weak_pointer. The first decrements the refcount to zero, and the second increments it again. Is the object destructed? I'm using a specific mechanism to support this and related features, and I don't see that in your code. Is the Boost implementation for Windows (32 and 64-bit) robust and lock-free in cases like this? How does it work? --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

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boost 1.40 beta libs, no longer include compiler version/boost version ?
by Avi Bahra 18 Aug '09

18 Aug '09

Volodya wrote: > The default naming of libraries in Unix-like environment now matches system conventions, and does > not include various decorations. > > Does this answer your question? Ok so it was done deliberately. Why the change, the decorations were useful in denoting the kind of library ? How stable is this decision is likely to change, between now and the release.? -- Best regards, Ta, Avi

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Random library, discrete distribution
by Kevin Martin 18 Aug '09

18 Aug '09

I made a post sometime last year about requiring a distribution that could generate enums with specified probabilities. I find I am regularly requiring a discrete distribution like this - where I specify the probabilities. Am I the only one who requires it, or would it be useful to a wider audience? I'm just wondering whether to submit a feature request for it or not? Thanks, Kevin Martin This is what I'm using at the moment: template<class IntType = int> class discrete_distribution { public: typedef boost::uniform_int<>::input_type input_type; typedef IntType result_type; template<size_t N> discrete_distribution(const boost::array<int, N> &outputs, const boost::array<int, N> &weights) : outputs_(outputs.begin(), outputs.end()), weights_(weights.begin(), weights.end()) { for(int i=1;i!=weights_.size();++i) weights_[i] += weights_[i-1]; } inline void reset() {} template<class Engine> result_type operator()(Engine& eng) { boost::uniform_int<> ui(0, weights_.back()-1); boost::variate_generator<Engine&, boost::uniform_int<> > vg(eng, ui); int idx = std::lower_bound(weights_.begin(), weights_.end(), vg()) - weights_.begin(); return outputs_[idx]; } private: std::vector<int> outputs_; std::vector<int> weights_; };

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Re: [Boost-users] Iterating over the seconds of a list of pairs
by Hicham Mouline 17 Aug '09

17 Aug '09

> > -----Original Message----- > > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users- > > bounces(a)lists.boost.org] On Behalf Of Björn Karlsson > > Sent: 08 August 2009 18:12 > > To: boost-users(a)lists.boost.org > > Subject: Re: [Boost-users] Iterating over the seconds of a list of pairs > > > > You're right -- transform_iterator is the right tool for the job. Try > > something like this. > > > > 1) Write a function object that extracts the second element of the pair. > > 2) Use the transform iterator adaptor to provide you with the type of > > the iterators for your class. > > 3) Use the helper function make_transform_iterator in your begin() and > > end() methods to create the iterators. > > > > Here's an example that does the above: > > > > #include <iostream> > > #include <list> > > #include <utility> > > > > #include "boost/iterator/transform_iterator.hpp" > > > > // Extract the second element of a pair > > template <typename T> class pair_second_t { > > public: > > typedef T result_type; > > > > template <typename U> T operator()(const std::pair<U,T>& element) > > const > > { > > return element.second; > > } > > }; > > > > class some_class > > { > > public: > > typedef std::list<std::pair<double,float> > container_type; > > typedef boost::transform_iterator<pair_second_t<float>, > > container_type::iterator> iterator_type; > > Bjorn Karlsson Hello bjorn, I have a similar problem. I have a vector< pair<LeftT, RightT> >. I'm very happy to use vector< pair<LeftT, RightT> >::iterator The only extra is I'd like to name the functions GetLeft() and GetRight() and make them callable as: typedef vector< pair<LeftT, RightT> >::iterator stl_iterator; stl_iterator i = ...; i->GetLeft() and i->GetRight() // I can't do this obviously so: typedef boost::transform_iterator<functor, stl_iterator> my_iterator_type; Should functor provide GetLeft() and GetRight()? or should my_iterator_type derive from the result of transform_iterator<functor, stl_iterator> ? regards,

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Help in using smart (double) pointers
by Sundaram 17 Aug '09

17 Aug '09

Howdy I'm very new to Boost libraries, and this is my first try in using it, so pardon my naive questions. Now for the question: I'm trying to port a Java module to C++, as in a J2ME game to Windows Mobile. I've re-written all the classes that the game code depends on the J2ME packages using Windows Mobile's native methods. Now for the last difference between the two: memory. The game code has lots of new and obviously no deletes, since Java has automatic garbage collection. So for the C++ equivalent , I thought of going for smart pointers, so that I needn't bother about memory leaks and to call delete for all news. I've no problem in using smart pointers for normal dumb pointers. While it is the double pointers that I'm confused of. Say if I have: int **palette = new int* [5]; palette[0] = new int[10]; palette[1] = new int[7]; ... ... what is the boost equivalent that I can use, so that when all references to palette's are released, all memory allocated in the name of palette should be freed i.e. both the single (palette[0], etc.) and double pointer (**palette) should be freed. If yes, can you please show me how? Thanks! Sundaram

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[1.40.0] Beta 1 available
by Beman Dawes 17 Aug '09

17 Aug '09

Boost release 1.40.0 beta 1 is available from SourceForge: http://sourceforge.net/projects/boost/files/ This release contains no new libraries, but contains numerous bug fixes for existing libraries. Boost source files with types .bz2 and .gz are created with POSIX-style (\n) line endings. Source files with types .7z and .zip are created with Windows-style (\r\n) line endings. The content is otherwise identical. Be sure to download a file with the appropriate line endings for your platform. If you are new to Boost, be sure to read the Getting Started Guide. See www.boost.org There are three known issues with beta 1: * boost/detail/scoped_enum_emulation.hpp, used by Boost.Filesystem, has a name conflict (enum_t) with Unix header rpc/types.h. Fixed in trunk, but not yet merged into the release. * Boost.Python has fixes in trunk not yet merged into to the release. * Boost.Signals has has fixes in trunk not yet merged into to the release. These issues will be resolved for the final 1.40.0 release. Other than these three known issues, please report any problems with the beta on the developers or users mailing lists. Unless unexpected problems arise, the plan is to ship the final 1.40.0 release in a week to ten days. Thanks, --The Boost release team

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[random] Singleton engine
by Diederick C. Niehorster 17 Aug '09

17 Aug '09

Hi All, I have been writing a wrapper around the variate_generator as I always want to use the same number generator, but do want to use different distributions. As I want to use only one instance of the engine instance for all instanced of my random number generator class, I used a singleton pattern. as is my first time using it, I decided to test it generously, to try and see if the same instance of the enigine is used. So not only did i check if the engine pointer for different instances of my random class is the same, but i also checked if the destructor for the engine (does not) get called (i've added a constructor to the boost header file temporarily) and whether the random numbers generated are indeed not the same. It seems my code does not work, the destructor gets called weirdly often, e.g., 4 times every time i initialize my random class. Also, the numbers generated by the two generators are the same, indicating the engine is reinitialized for every instance of my random class. Yet, the pointer to the engine is the same (note that it is also the same if i dont call the destructor in between). I am using MSVC 2008 on windows XP 32 bit. What am I doing wrong? As I am learning, any other feedback is also very welcome. Best, Diederick ---- output of run of code below: check 0 00000000 ctor 1 destructor destructor destructor destructor after ctor 1 003462E0 random: 8148 dtor 1 destructor ctor 2 destructor destructor destructor destructor after ctor 2 003462E0 random: 8148 destructor destructor ---- code // includes #include <boost/random.hpp> #include <time.h> #include <iostream> using namespace std; // declaration template<class Dist> class CRandom { public: /** use for Dist: CRandomI Ci(min,max); uses uniform_int<int> - integral types CRandomR Cr(min,max); uses uniform_real<double> - floating point types for other ditributions or types, use: CRandom<distribution<optional type>> Cr(0--3 params, depending on distribution); for distributions and params, see: http://www.boost.org/doc/libs/1_39_0/libs/random/random-distributions.html */ // forwarding constructors explicit CRandom() : Gen(*EngineSingleton::Eng(), Dist()) { } template<class P> explicit CRandom(const P & p1) : Gen(*EngineSingleton::Eng(), Dist(p1)) { } template<class P> explicit CRandom(const P & p1, const P & p2) : Gen(*EngineSingleton::Eng(), Dist(p1, p2)) { } template<class P> explicit CRandom(const P & p1, const P & p2, const P & p3) : Gen(*EngineSingleton::Eng(), Dist(p1, p2, p3)) { } ~CRandom(void) {}; typedef typename Dist::result_type result_type; result_type operator()() { return Gen(); } template<class T> result_type operator()(T value) { return Gen(value); } private: boost::variate_generator<boost::mt19937,Dist> Gen; }; // end declaration // shorthand typedefs typedef CRandom<boost::uniform_int<int>> CRandomI; // even int is default type , specify it in case it ever changes typedef CRandom<boost::uniform_real<double>> CRandomR; // even double is default type, specify it in case it ever changes /** engine wrapper class following singleton pattern, so every instantiation of CRandom uses the same engine based on: http://www.aristeia.com/Papers/DDJ_Jul_Aug_2004_revised.pdf */ // declaration class EngineSingleton { public: static boost::mt19937* Eng(); static boost::mt19937* GetEngPoint() {return pEng;}; // for test only protected: // disallow (copy) construction and assignment operator EngineSingleton(); EngineSingleton(const EngineSingleton&); EngineSingleton& operator=(const EngineSingleton&); private: static boost::mt19937* pEng; }; // end declaration // implementation boost::mt19937* EngineSingleton::pEng = NULL; boost::mt19937* EngineSingleton::Eng() { if (pEng == NULL) { pEng = new boost::mt19937(/*unsigned int(time(NULL))*/); // initialize with same seed always, for test only } return pEng; } // end implementation //main int main(int argc, char* argv[]) { cout << "check 0" << endl; cout << EngineSingleton::GetEngPoint() << endl; cout << "ctor 1" << endl; CRandomI Cr(1,10000); cout << "after ctor 1" << endl; cout << EngineSingleton::GetEngPoint() << endl; int test = Cr(); cout << "random: " << test << endl; cout << "dtor 1" << endl; Cr.~CRandom(); cout << "ctor 2" << endl; CRandomI Cr2(1,10000); cout << "after ctor 2" << endl; cout << EngineSingleton::GetEngPoint() << endl; int test2 = Cr2(); cout << "random: " << test2 << endl; // exit return 1; }

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