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How to catch boost_queue returns false

I am using boost :: interprocess :: message_queue and as per the definition given at http://www.boost.org/doc/libs/1_35_0/doc/html/boost/interprocess/message_queue.html

message_queue(open_only_t open_only, const char * name);
  • Opens a previously created public message queue named "name". If no resources were created earlier or there are no free resources, the function returns false.

now what i can't figure out is how the constructor returns the value? although he claims that the function returns false ", but afaik message_queue must be a constructor.

and also if it returns false, can I catch this in a boolean variable?

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1 answer


Instead, it will select

A boost::interprocess::interprocess_exception

as the current documentation suggests.

So,

using namespace boost::interprocess;
try {
    //Create a message_queue. If the queue
    //exists throws an exception
    message_queue mq
        (create_only         //only create
         ,"message_queue"     //name
         ,100                 //max message number
         ,100                 //max message size
        );
} catch (interprocess_exception const& ipe)
{
    std::cerr << "Error: #" << ipe.get_error_code() << ", " << ipe.what() << "\n";
}


On restart it will print

Error: #9, File exists
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