July 2010 - Boost-users - lists.preview.boost.org

OpenMPI cannot get the results from workers
by Jack Bryan 06 Jul '10

06 Jul '10

Dear All : I designed a master-worker framework, 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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[Boost.Uuid] Passing UUIDs with MPI
by Didier Devaurs 06 Jul '10

06 Jul '10

Hello, I'm having troubles trying to pass a uuid with MPI routines. Since a uuid is serialized as a primitive type, I was expecting it could be declared as an MPI datatype using: BOOST_IS_MPI_DATATYPE(boost::uuids::uuid) and sent via MPI routines. I've written a short program to illustrate the problem. It compiles but produces a "segmentation fault" error when I'm trying to run it: #include <iostream> #include <boost/mpi.hpp> #include <boost/uuid/uuid.hpp> #include <boost/uuid/uuid_io.hpp> #include <boost/uuid/uuid_generators.hpp> #include <boost/uuid/uuid_serialize.hpp> BOOST_IS_MPI_DATATYPE(boost::uuids::uuid) int main() { boost::mpi::environment env; boost::mpi::communicator world; if (world.rank() == 0) { boost::uuids::uuid u; u = boost::uuids::random_generator()(); std::cout << "u = " << u << std::endl; world.send(1, 0, u); } else { boost::uuids::uuid v; world.recv(0, 0, v); std::cout << "v = " << v << std::endl; } return 0; } Does anybody have an idea whether passing uuids would be possible, and if yes what is wrong in my code? Thank you, Didier Devaurs

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Boost UUIDS: string generator is crashing
by Carla Strembicke 06 Jul '10

06 Jul '10

I am using the following in my program for proof of concept. ( This was extracted straight from the documentation) boost::uuids::string_generator gen; boost::uuids::uuid u1 = gen("{01234567-89ab-cdef-0123456789abcdef}"); crashing in : template <typename CharIterator> uuid operator()(CharIterator begin, CharIterator end) const crashing at : *it_byte = get_value(c) Is this a bug or am I doing something wrong. When I remove the dashes it seems to work...... CONFIDENTIAL INFORMATION NOTICE: The information contained in this e-mail is privileged, confidential and intended solely for the use of the addressee named above. If the reader of this e-mail is not the intended recipient, you are hereby notified that any dissemination, distribution or copying of this e-mail is strictly prohibited. If you received this in error, please contact the sender and destroy all copies of this e-mail. Thank you.

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Is there any existing/similar C++ lib for Java FileChannel class?
by Bo Xie 05 Jul '10

05 Jul '10

Hello, Java FileChannel ( http://java.sun.com/j2se/1.4.2/docs/api/java/nio/channels/FileChannel.html) supports to lock a region of the file [e.g.lock(long position, long size, boolean shared)]. Is there any existing/similar C++ lib for it (so than I need not to reinvent the wheel)? Best Regards, Bo Xie

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Boost utility to get const value_type for const std containers?
by Mostafa 05 Jul '10

05 Jul '10

Hi all, Is there a boost utility that will return the "correct" value_type for std containers? i.e., for: typedef std::vector<char> const CharVector; is there SomeBoostUtility<CharVector>::Type == char const ? Thanks, -Mostafa

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checking whether a variable is between two values using boost.interval
by Sean Farrow 05 Jul '10

05 Jul '10

Hi: I have a variable, can I use boost.interval to check whether it is between two values? If so how would I go about doing this? Cheers Sean.

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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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