April 2012 - Boost-users - lists.preview.boost.org

How to terminate a specific thread among other threads
by Master 15 Apr '12

15 Apr '12

Hello all . i have been trying to selectively dispose a thread among some other threads , but so far i wasnt successful in finding a way to do it . suppose i have a simple function which identifies any threads which gets into it and if a specific one is located ,it is disposed . simply sth like this : #include <boost/signal.hpp> #include <iostream> #include <boost/thread.hpp> using namespace std; boost::thread threadarray[3]; int t(int x) { boost::id id(); switch(boost::this_thread::get_id()) { case threadarray[0].get_id(): cout<<"thread 1"; break; case threadarray[1].get_id(): * DISPOSE THIS THREAD or CHANGE OWNERSHITP, OR GET ANOTHER JOB TO IT , OR CHECK IF IT WAS SUCCESSFUL OR NOT* break; case threadarray[3].get_id(): cout<<"thread 3"; break; default: cout<<"default"; } return 0; } int main() { boost::thread t1(t,5), t2(t,6),t3(t,7); threadarray[0] = t1.move(); threadarray[1] = t2.move(); threadarray[2] = t3.move(); for(int i = 0; i <3;i++) { threadarray[i].join(); } system("pause"); } i cant either use a switch statement to identify which thread im dealing with at the moment , nor can i find any means to keep track of my threads , and manage them in situations like this ( i already tried vector(boost::thread> my vect; and tries to use std::for_each(vect.begin(),vect.end(),somefunction_accepting boost::thread) , this doesnt work !! ) any idea how i can achieve sth similar? Thanks in advance

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[Boost State Chart] Where to include, where to declare?
by Philipp Bender 15 Apr '12

15 Apr '12

Hi all, today I face some major problems with the state charts. Mostly this comes from incorrect forward declarations and so on. I use this scheme for e.g. decaring a state which has orthogonal substates. I hope my pseudocode is readable. ############# Outer.h ############## struct Inner1 struct Inner2 struct Outer < Context, InnerDefaults< Inner1, Inner2> > { // implementation } #include Inner1 // this is the really important part #include Inner2 ############## Inner(1|2).h ######## struct Inner(1|2) < Outer > { // implementation } ################################# Doing so, I am able to use Outer in the Inner files without including something and so on -- but as soon as I start to create a file called "Inner1.cpp" and only write '#include "Inner.h" ' the problems start and the compiler complains that "Outer" ist not declared (what is true I guess). What works is to include the "Outermost" which is the state machine in my case ... but this would mean that every state knows about my state machine. Also, in my approach the cpp files need to be recompiled completely every time I think also if only the header of a completely unrelated state changes (because each cpp includes the complete state chain). So ... what's the suggested way to go? I'd like to have as little dependencies as possible, so not "all_forward_declarations.h" or some such. I had it like that, and it was a big mess. And I like the states to be separated ... Best regards, Philipp

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Set fusion::vector value with boost::shared_ptr
by Stefan Troeger 15 Apr '12

15 Apr '12

Hello alltogether, I've posted this already in Stackoverflow a week ago with no answer up to now, so I thougth I try it here again. I want to set a value in a fusion::vector at a specific location. This works normaly very well with fusion::at_c(seq) = value, as at_c returns a reference to the object at this position. However, this is not garanted, the documentation only states about the return type: "In most cases, this is a reference". I've encounterd a case where it is not a reference, when the objects are of type boost::shared_ptr<anytype>. Therefore I cant set the values as I'm only overriding a temporary. Minimal example: struct Object1{}; struct Object2{}; typedef fusion::vector<boost::shared_ptr<Object1>, boost::shared_ptr<Object2> > seq_type; seq_type seq; boost::shared_ptr<Object1> value(new Object1()); fusion::at_c<0>(seq) = value; assert(fusion::at_c<0>(seq) ); //assert will be executed because the default constructed empty pointer was not overridden with a valid one BOOST_MPL_ASSERT(( boost::is_reference< result_of::at_c<seq_type, 0>::type > )) //compilation fails because the returned type is not a reference What is a valid alternative of setting the pointers in an fusion sequence? Any help would be appreciated! Thanks, Stefan

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[Boost] List of not header-only libraries (requiring linking).
by Klaim - Joël Lamotte 14 Apr '12

14 Apr '12

Hi, I was looking on the website about a list of the boost libraries that require linking/ are not header only. Is it correct that this list is what I'm looking for? http://www.boost.org/doc/libs/?view=filtered_autolink If it is, then I think the name is misleading. Automatic linking happens only with visual studio, right? Also, autolink doesn't really mean anything in this context, so maybe something like "Linking Required" would be better? I also found the list I was looking for there: http://www.boost.org/doc/libs/1_49_0/more/getting_started/windows.html But I had to remember it was there to find it. So I think that people wanting to know this don't go on this page first, they will look at some filter in the library list pages instead. Making it more clear would be helpful, in my opinion. Joël Lamotte

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Open Source Credit Rating Tool Using Boost
by Marc Joffe 14 Apr '12

14 Apr '12

I am looking for users and developers interested in collaborating on an open source sovereign rating model project. If you don't agree with your country's credit rating, here is a chance to do something about it! A pre-release version of the tool is available at http://www.publicsectorcredit.org/pscf.html. Source will be posted to GitHub on 2 May 2012. The tool uses a Monte Carlo simulation which includes calls to Boost's normal and Cauchy random number generators. There are many opportunities for improvement upon the initial version. A blog post explaining the need for this project can be found at: Rating Agency Models and Open Source http://expectedloss.blogspot.com/2012/04/credit-rating-agency-models-and-ope n.html Please contact me if interested. Regards, Marc Joffe Public Sector Credit Solutions marc(a)publicsectorcredit.org

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[Fwd: Error while typecasting the boost::variant ( need help)]
by Baba Prasad 13 Apr '12

13 Apr '12

Dear Friend due to hurry I did sent proper error message so pls have look now. my program is typedef std::vector<std::string> vec_name; struct network { boost::variant<vec_name> net_id; }; typedef std::vector<network>network_list; // create the instance for vector network_list net_list; for(int i=0; i<net_list.size(); ++i) { unsigned char* query_str = net_list[0].net_id; } ERROR is error: cannot convert boost::variant<std::vector<std::basic_string<char> > > to unsigned char* in assignment Best Regards BaBu -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

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Error while typecasting the boost::variant ( need help)
by Baba Prasad 13 Apr '12

13 Apr '12

Dear Friend my program is typedef std::vector<int> vec_name; struct network { boost::variant<vec_name> net_id; }; typedef std::vector<network>network_list; // create the instance for vector network_list net_list; for(int i=0; i<net_list.size(); ++i) { unsigned char* query_str = net_list[0].net_id; } ERROR is error: cannot convert boost::variant<odtone::mih::null, std::vector<std::basic_string<char> > > to unsigned char* in assignment Best Regards BaBu -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

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How to type cast the boost ::variant
by Baba Prasad 13 Apr '12

13 Apr '12

Dear Friends, I have almost similar kind of program typedef std::vector<int> vec_name; struct network { boost::variant<vec_name> net_id; }; typedef std::vector<network>network_list; in main when I am extracting content of network_list vector in the following manner // create the instance for vector network_list net_list; for(int i=0; i<net_list.size(); ++i) { unsigned char* query_str = net_list[0].net_id; } when I am doing like this in the above line of code the bellow error is giving , but what I understand is I am not properly typecasting. Please can any one will help me how get out of this problem Error is: error: cannot convert boost::variant<odtone::mih::null, std::vector<std::basic_string<char> > > to unsigned char* in assignment Best Regards BaBu -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

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Official boost Git repository?
by niXman 13 Apr '12

13 Apr '12

Hello list, Tell me please, is there an official boost Git repository? Thanks! -- Regards, niXman

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Interrupting interprocess::message_queue::receive
by Michael Herrmann 13 Apr '12

13 Apr '12

Hi all, I am receiving messages from a message_queue via the blocking receive(...)-method from a separate boost::thread. When I interrupt this thread, the receive(...)-method never returns (not even with an thread::thread_interrupted exception). Am i doing something wrong or could this be a bug in message_queue? The situation I am talking about is illustrated by the following program never returning: #include <boost/thread.hpp> #include <boost/interprocess/detail/config_begin.hpp> #include <boost/interprocess/ipc/message_queue.hpp> #include <iostream> #include <vector> using namespace boost::interprocess; void receive() { try { message_queue mq(open_or_create, "message_queue", 100, sizeof(int)); unsigned int priority; message_queue::size_type recvd_size; int number; std::cout << "Trying to receive one int..." << std::endl; mq.receive(&number, sizeof(number), recvd_size, priority); } catch(interprocess_exception &ex) { message_queue::remove("message_queue"); std::cout << "Exception occurred: " << ex.what() << std::endl; } catch(boost::thread_interrupted &ex) { std::cout << "Thread interrupted. " << std::endl; } } int main() { message_queue::remove("message_queue"); boost::thread t(receive); t.interrupt(); t.join(); } #include <boost/interprocess/detail/config_end.hpp> Thanks! Michael

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