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Priority of io_service in a multithreaded application
by Gözde Bahar KOŞ 05 Jul '10

05 Jul '10

Hi, I have a question about priority of io_service in a multithreaded application. I'm using async_read function to read some bytes from serial port in one thread. And application has other threads. Does this io_service inherit the priority of the calling thread? If not how can i set the priority of this io_service? Thanks, Best Regards, Gözde Koş ###################################################################### Dikkat: Bu elektronik posta mesaji kisisel ve ozeldir. Eger size gonderilmediyse lutfen gondericiyi bilgilendirip mesaji siliniz. Firmamiza gelen ve giden mesajlar virus taramasindan gecirilmekte, guvenlik nedeni ile kontrol edilerek saklanmaktadir. Mesajdaki gorusler ve bakis acisi gondericiye ait olup Aselsan A.S. resmi gorusu olmak zorunda degildir. ###################################################################### Attention: This e-mail message is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. E-mails to and from the company are monitored for operational reasons and in accordance with lawful business practices. Any views or opinions presented are solely those of the author and do not necessarily represent the views of the company. ######################################################################

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[date_time] How to parse "5th" into day of month?
by Adam Nielsen 05 Jul '10

05 Jul '10

Hi all, I'm a bit stuck with the date_time module. I found a few examples (ironically from bug reports) since I couldn't find any on the Boost documentation site, as I am trying to parse a string in the format "Fri 5th March 2010, 05:01pm" into a boost::gregorian::date structure. Unfortunately I can't figure out how to get it to recognise "5th". It works fine if the day is two digits, but for a single digit it returns the error "Day of month value is out of range 1..31" My date string is "%a %e.. %B %Y" (not sure if the ".." is correct but it was the only way I could get it to ignore the "th" after the day - again, I couldn't find anything about doing that in the docs.) Does anyone know whether it's possible to parse a date with a single digit day in it? Some of the docs hint that it's possible and give sample dates in that format, but they don't include the matching format specifiers to use. Here is my code: std::string strDate = "Fri 5th March 2010, 05:01pm"; std::string format("%a %e.. %B %Y"); boost::date_time::format_date_parser<boost::gregorian::date, char> parser(format, std::locale("C")); boost::date_time::special_values_parser<boost::gregorian::date, char> svp; boost::gregorian::date d = parser.parse_date(strDate, format, svp); std::cout << "Converted date from \"" << strDate << "\" to " << d << std::endl; Any suggestions would be much appreciated, or pointers to the correct documentation because I'm having real trouble finding where this sort of thing is explained :-( Many thanks, Adam.

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Deadlock with boost::asio::ip::tcp::iostream‏
by Jeff Pai 05 Jul '10

05 Jul '10

Hi everyone, I took the daytime example and add a request this iostream, and it starts deadlocking in windows environment. Is this the wrong way to do it? int main(int argc, char* argv[]) { try { if (argc != 2) { std::cerr << "Usage: daytime_client <host>" << std::endl; return 1; } tcp::iostream s(argv[1], "daytime"); s << "request"; std::string line; std::getline(s, line); std::cout << line << std::endl; } catch (std::exception& e) { std::cout << "Exception: " << e.what() << std::endl; } return 0; } void server() { try { boost::asio::io_service io_service; tcp::endpoint endpoint(tcp::v4(), 13); tcp::acceptor acceptor(io_service, endpoint); for (;;) { tcp::iostream stream; acceptor.accept(*stream.rdbuf()); std::string req; stream >> req; stream << make_daytime_string(); } } catch (std::exception& e) { std::cerr << e.what() << std::endl; } } _________________________________________________________________ The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with Hotmail. http://www.windowslive.com/campaign/thenewbusy?tile=multicalendar&ocid=PID2…

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How to get tuple member type ?
by Timothy Madden 05 Jul '10

05 Jul '10

Hello I have constructed a type of STL containers and tuples in my prgogram, and even though I have a typedef for it, when I use it I often need the inner types involved. Now STL has the value_type declarations for all containers, but for tuples is there a documented way to get the type of a tuple member ? Or the type of the tuple<>::get<>() function ? Thank you, Timothy Madden

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Some results for planar graph coloring algorithm
by Mike Douglass 04 Jul '10

04 Jul '10

I have uploaded Planar6_July3.tz to http://groups.google.com/group/graph_coloring_program (README_July3) . It contains 100 maximal planar graphs of 50 vertices each. The graphs were generated using LEDA's function maximal_planar_graph(graph, number_of_vertices). I applied my graph coloring program "pl" in batch mode (using a perl script) to a directory containing the 100 graphs and it succeeded in finding a proper 4 coloring for EVERY SINGLE GRAPH. Average solution time per graph - about 1 second, of which a large part was probably disk read/writes. Does anyone have a favorite planar graph of <= 50 vertices that I can try my algorithm on? 50 vertices is not very large, but soon I hope to try graphs of 60, 70 or more vertices. I ran fr_layout on the 100 graphs but the resulting layout was not very clear. I think what I really need is a layout on a sphere and a way to look at the sphere from any angle. Does anyone know of such a thing. In the not too distant future I hope to be looking at graphs of up to 100 vertices. Anything but a spherical layout i believe would be too messy. You can find a clear graphical depiction of the algorithm at http://groups.google.com/group/graph_coloring_B1

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vector iterator element-wise operation
by Max S. Kaznady 04 Jul '10

04 Jul '10

I'm using this example: http://stackoverflow.com/questions/773667/element-wise-operations-with-boos… and for some reason the function std::fill compiles and works just fine, but functions std::for_each and std::transform do no compile - saying that there is no compatible function found for the iterator type. using namespace boost::numeric::ublas; // Create a 30 element vector of doubles vector<double> vec(30); // Assign 8.0 to each element. std::fill(vec.begin(), vec.end(), 8.0); // Perform the "Gamma" function on each element and assign the result back // to the original element in the vector. // The next line does not compile, but the fill function compiles and executes just fine: std::transform(vec.begin(), vec.end(), vec.begin(), boost::math::tgamma); What's wrong? Cheers, Max

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boost MPI, cannot get the results from workers
by Jack Bryan 04 Jul '10

04 Jul '10

Dear All : I designed a master-worker framework with boost MPI, in which the master can schedulemultiple tasks (numTaskPerWorkerNode) to each worker and then collects results from workers. if the numTaskPerWorkerNode = 1, it works well. But, if numTaskPerWorkerNode > 1, the master cannot get the results from workers. But, the workers can get the tasks from master. why ? I have used different taskTag to distinguish the tasks, but still does not work. Any help is appreciated. Thanks, Jack July 4 2010 _________________________________________________________________ Hotmail has tools for the New Busy. Search, chat and e-mail from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:…

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Re: [Boost-users] [boost.tuple] issue
by Niels Dekker - address until 2010-10-10 04 Jul '10

04 Jul '10

On 2010-07-04-Sun 16:14, Sean Farrow wrote: > boost::make_tuple(false, NULL); NULL is typically defined as an int (0)! HTH, Niels -- Niels Dekker http://www.xs4all.nl/~nd/dekkerware Scientific programmer at LKEB, Leiden University Medical Center

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Re: [Boost-users] [boost.tuple] issue
by Niels Dekker - address until 2010-10-10 04 Jul '10

04 Jul '10

On 2010-07-04-Sun 15:18, Sean Farrow wrote: > I’ve got a tuple defined as: > Boost::tuple<bool, HWND> > > And when I do: > Boost::make_tuple(true, TempWindow); > > I get the error > C2440 cannot convert from int to hwnd__* > > Anyone got any ideas? > Visual c++ 2008, and boost 1.43. I guess the type of your TempWindow might not be HWND...? Otherwise maybe you should post a code snippet to clarify what you're trying to compile! HTH, Niels -- Niels Dekker http://www.xs4all.nl/~nd/dekkerware Scientific programmer at LKEB, Leiden University Medical Center

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[boost.tuple] issue
by Sean Farrow 04 Jul '10

04 Jul '10

Hi: I've got a tuple defined as: Boost::tuple<bool, HWND> And when I do: Boost::make_tuple(true, TempWindow); I get the error C2440 cannot convert from int to hwnd__* Anyone got any ideas? Visual c++ 2008, and boost 1.43. Cheers Sean.

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