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what are movable objects
by Abbhishek Misra 06 Jul '10

06 Jul '10

Hello Boost Users, I'm trying to learn multi threading in C++. http://www.boost.org/doc/libs/1_39_0/doc/html/thread/thread_management.html says "Objects of type boost::thread are movable, however, so they can be stored in move-aware containers, and returned from functions." Please help me understand what are movable objects. reagrds Abhishek

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using system:error_code
by Lloyd 06 Jul '10

06 Jul '10

Hi, How can I interpret and use the error_code in my application? As an example my ASIO async_read "handler function" receives one argument as error, as shown below void MyClass::AsyncReadHandler(const boost::system::error_code& error,std::size_t bytes_transferred) { } How can I inrterpret the "error" in a meaningful way? error.message() returns the meaning of the error and and error.value() returns an integer code associated with the error. So far fine, but how can I use it in a comparison operator in a portable way... if(error.value()==2) //Not readable { } if(error.value()==END_OF_FILE) //More readable { } So how can I get the respective "enum" associated with the error Thanks a lot, Lloyd ______________________________________ Scanned and protected by Email scanner

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[tuple] set_open manipulator
by Hicham Mouline 06 Jul '10

06 Jul '10

Hello I am trying to remove the ( bracket from the output of a tuple. So I've called stream << boost::tuples::set_open( static_cast<char>(0) ) << boost::tuples::set_close( static_cast<char>(0) ) << tuple; however, the brackets are still printed. PS: when I used '' instead of static_cast<char>(0), gcc complained about empty character constant. Rds,

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Is there any asynchronous file read/write Boost lib?
by Bo Xie 06 Jul '10

06 Jul '10

Hello, As I know, Boost.Asio is for asynchronous network socket, not asynchronous file read/write. Is there any asynchronous file read/write Boost (or other cross platform) lib? Best Regards, Bo Xie

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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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