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Graph and external properties
by g4hx 24 Nov '11

24 Nov '11

Hello everyone, I am currently trying to implement a graph algorithm using boost::graph but I ran into a problem which I don't know how to fix. I already asked this question http://stackoverflow.com/questions/8234910/external-property-map-tied-to-st… but I got no answer yet, apart from someone telling me that "Boost.Graph" is borderline unusable. I thought that you people wouldn't let this stand, so I am just asking you: I need some variables stored in a vector to be accessible via an operator[](edge_descriptor&), I think that this could be done using external properties, but since I already use bundled internal properties, I am not sure how to go ahead. I basically need something as in http://www.boost.org/doc/libs/1_36_0/libs/property_map/iterator_property_ma…. I would very much appreciate it someone would just drop me a few lines of code to illustrate how to solve the problem. g4hx

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[Thread] program crashes from time to time when deleting unique_future<void>
by Soderback, Johan 24 Nov '11

24 Nov '11

Hi, I have a small example program that crashes from time to time. I would appreciate some help to understand why. In function run() executed on the main thread I create a packaged_task (pt), put it in a queue (_q) and wait for it to get executed (fu.get()). In another thread the tasks are executed when the queue _q is populated. The task I'm running always throws/rethrows intentionally. It results (from time to time) in an access violation when the unique_future, fu, is deleted. See the stack trace at the bottom. Anybody see any flaws in this design? I have tried 1.47.0 and 1.48.0, MSVC 2005. Here's the code. ***************************************************** #include <boost/exception/all.hpp> #include <boost/thread.hpp> #include <sstream> #include <iostream> struct Exception : public virtual std::exception , public virtual boost::exception { }; struct TheException : public virtual Exception {}; void throwf() { try { BOOST_THROW_EXCEPTION(TheException()); } catch (...) { boost::current_exception_diagnostic_information(); throw; } } struct Test { Test() { _t.reset(new boost::thread(boost::bind(&Test::executor, this))); } ~Test() { _t->join(); } void executor() { for (;;) { boost::unique_lock<boost::mutex> lk(_mx); while(_q.empty()) { _cv.wait(lk); } boost::shared_ptr< boost::packaged_task<void> > pt = _q.front(); _q.pop_front(); lk.unlock(); (*pt)(); } } void run() { for (;;) { const int N = 20000; for (int j = 0; j < N; ++j) { boost::shared_ptr< boost::packaged_task<void> > pt(new boost::packaged_task<void>(throwf)); boost::unique_future<void> fu = pt->get_future(); { boost::unique_lock<boost::mutex> lk(_mx); _q.push_back(pt); pt.reset(); } _cv.notify_one(); try { fu.get(); assert(false); } catch (const TheException& ) { } catch (const boost::exception& ) { assert(false); } catch (...) { assert(false); } } std::cout << "."; } } private: boost::mutex _mx; std::list< boost::shared_ptr< boost::packaged_task<void> > > _q; boost::shared_ptr<boost::thread> _t; boost::condition_variable_any _cv; }; int main(int, char*) { Test test; test.run(); } ***************************************************** Here is the callstack, program terminated with access violation. Unhandled exception at 0x0043196b in crasher.exe: 0xC0000005: Access violation reading location 0xdddddded. > crasher.exe!boost::exception_detail::refcount_ptr<boost::exception_detail::error_info_container>::release() Line 78 + 0x18 bytes C++ crasher.exe!boost::exception_detail::refcount_ptr<boost::exception_detail::error_info_container>::~refcount_ptr<boost::exception_detail::error_info_container>() Line 35 C++ crasher.exe!boost::exception::~exception() Line 278 + 0xb bytes C++ crasher.exe!boost::exception_detail::clone_impl<TheException>::`vbase destructor'() + 0x41 bytes C++ crasher.exe!boost::exception_detail::clone_impl<TheException>::`scalar deleting destructor'() + 0x2b bytes C++ crasher.exe!boost::checked_delete<boost::exception_detail::clone_base const >(const boost::exception_detail::clone_base * x=0x006f7d10) Line 34 + 0x35 bytes C++ crasher.exe!boost::detail::sp_counted_impl_p<boost::exception_detail::clone_base const >::dispose() Line 78 + 0xc bytes C++ crasher.exe!boost::detail::sp_counted_base::release() Line 102 + 0xf bytes C++ crasher.exe!boost::detail::shared_count::~shared_count() Line 309 C++ crasher.exe!boost::shared_ptr<boost::exception_detail::clone_base const >::~shared_ptr<boost::exception_detail::clone_base const >() + 0x2e bytes C++ crasher.exe!boost::exception_ptr::~exception_ptr() + 0x2b bytes C++ crasher.exe!boost::detail::future_object_base::~future_object_base() Line 106 + 0x9c bytes C++ crasher.exe!boost::detail::future_object<void>::~future_object<void>() + 0x2b bytes C++ crasher.exe!boost::detail::task_base<void>::~task_base<void>() + 0x2b bytes C++ crasher.exe!boost::detail::task_object<void,void (__cdecl*)(void)>::~task_object<void,void (__cdecl*)(void)>() + 0x2b bytes C++ crasher.exe!boost::detail::task_object<void,void (__cdecl*)(void)>::`scalar deleting destructor'() + 0x2b bytes C++ crasher.exe!boost::checked_delete<boost::detail::task_object<void,void (__cdecl*)(void)> >(boost::detail::task_object<void,void (__cdecl*)(void)> * x=0x006f7b10) Line 34 + 0x34 bytes C++ crasher.exe!boost::detail::sp_counted_impl_p<boost::detail::task_object<void,void (__cdecl*)(void)> >::dispose() Line 78 + 0xc bytes C++ crasher.exe!boost::detail::sp_counted_base::release() Line 102 + 0xf bytes C++ crasher.exe!boost::detail::shared_count::~shared_count() Line 309 C++ crasher.exe!boost::shared_ptr<boost::detail::future_object<void> >::~shared_ptr<boost::detail::future_object<void> >() + 0x2e bytes C++ crasher.exe!boost::unique_future<void>::~unique_future<void>() Line 644 + 0x2b bytes C++ crasher.exe!Test::run() Line 95 + 0xc bytes C++ crasher.exe!main(int __formal=1, int __formal=1) Line 112 C++ crasher.exe!__tmainCRTStartup() Line 597 + 0x19 bytes C crasher.exe!mainCRTStartup() Line 414 C kernel32.dll!7c817067() [Frames below may be incorrect and/or missing, no symbols loaded for kernel32.dll] ________________________________ Please consider the environment before printing this e-mail. 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2 2

Iterate over template arguments
by Allan Nielsen 24 Nov '11

24 Nov '11

Hi, I have a set of old classes which I use for inter process communication: Example: template<typename T0, typename T1> class Interface2: public InterfaceBase { public: Interface2( const std::string & name, IPCManager * ipcmanager) : InterfaceBase(name, ipcmanager){ } Interface2( const std::string & name, boost::function<void ( const T0 & t0, const T1 & t1 ) > _f, IPCManager * ipcmanager) : InterfaceBase(name, ipcmanager), f(_f) { } virtual ~Interface2() { } boost::function<void ( const T0 & t0, const T1 & t1 ) > f; protected: void handler(IpcMsg & m) { if(! f.empty()){ if( m.value_size() != 2 ) { m.set_type(IpcMsg_Type_RESPONSE_FAILED_WRONG_VALUE_NUMBERS); return; } GMB_ARGUMENT_DESERILIZE(T0, 0); GMB_ARGUMENT_DESERILIZE(T1, 1); try { f(t0, t1); m.set_type(IpcMsg_Type_RESPONSE_OK); } catch (std::exception e) { m.set_type(IpcMsg_Type_RESPONSE_FAILED_EXCEPTION); } }else{ m.set_type(IpcMsg_Type_RESPONSE_FAILED_NO_FUNCTION_ATTACHED); } } IPCManager * ipc; }; It works fine, but it might not be the most elegant solution, and I would very much like to improve it. Today I have Interface0-10 which accept from 0 to 10 arguments, and InterfaceCaller0-10 which call an interface with 0-10 arguments. And another set of classes with an return value as well. What I would like is an interface where the following would be valid (much like boost function): Interface< int (int, std::string ) > if1(...) ; I known this might not be easy or the intension of c++99, but I would like to give it a try anyway... So, I would appreciate it if somebody could give me some pointers on how I can process each of the templates arguments. I do not have access to a c++0x compiler on the target where this is used. Best regards Allan W. Nielsen

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[locale] 1.48+stlport5.2.1: invalid conversion from `int' to `stlp_std::ctype_base::mask'
by Bogdan Slusarczyk 24 Nov '11

24 Nov '11

Hi, I tried to build boost1.48 with stlport5.2.1 (linux). I noticed such problem: libs/locale/src/posix/numeric.cpp:215: error: invalid conversion from `int' to `stlp_std::ctype_base::mask' This is simple problem like this one: enum Test { value } Test test; test|=value; //error is here I could use -fpermissive, however I think it's very intrusive. If you know other solutions let me know please. Best regards, Bogdan

2 2

multi_index_container + composite key
by Uthpal Urubail 24 Nov '11

24 Nov '11

All, Is it possible create a multi_index_container with keys in non sequenced order? i.e, in the below example while extracting the element book entry can I send the node1 and node2 in different order than how it is created? elementbook pb; Elem_entry fc1 = Elem_entry(1,90,99); Extracting: elementbook::iterator it; it = pb.find(boost::make_tuple(99,90)); ????? Is it possible to simulate this requirement? typedef multi_index_container< Elem_entry, indexed_by< //non-unique as some might have more than ids ordered_unique< composite_key< Elem_entry, member<Elem_entry,unsigned int,&Elem_entry::node1>, member<Elem_entry,unsigned int,&Elem_entry::node2> > >, ordered_unique< member<Elem_entry,unsigned int,&Elem_entry::faceid> > > > elementbook;

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Vertex Weights!!!
by Nouf M. 24 Nov '11

24 Nov '11

Hello, I have a graph that contains: - Vertices with 1.name 2.weight - Edges with 1.name 2.weight I couldnt figure out how to store the weights of the vertices. Is it possible to do that? if yes, then please tell me how... Thank you...

3 2

How to use mpl::count and function_types
by Allan Nielsen 24 Nov '11

24 Nov '11

Hi I'm trying to count the number of parameters in a function-type: cout << boost::mpl::count< boost::function_types::parameter_types< void() > >::value << endl; cout << boost::mpl::count< boost::function_types::parameter_types< void(int) > >::value << endl; cout << boost::mpl::count< boost::function_types::parameter_types< void(int, int) > >::value << endl; This prints: 0 0 0 I would have expected: 0 1 2 What have I done wrong? -- Allan W. Nielsen

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[iostreams] 7-zip filters
by Igor R 24 Nov '11

24 Nov '11

Hello, I tried to google around the subj, but couldn't find anything useful. Is it realy unavailble or have I just overlooked it? :) Thanks.

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Trivial logging with boost.log
by Konstantin Ribel 24 Nov '11

24 Nov '11

3 3

Question about boost.log (from Andrey Semashev )
by Steve Ong 23 Nov '11

23 Nov '11

Does anyone know why the boost.log never made it into the library? Thanks, Steve

3 2