Boost Thread: Use of deleted function Error

问题:

I am trying to use a multi-threading in boost to handle multiple requests and upon the reception of a specific message I will create a new thread to handle it as below:

main.cpp

/**
* Destination Machine Request Handler.
*
* @param msg Received message.
* @param ec Error code.
*/
void handover_request_handler(odtone::mih::message &msg, const boost::system::error_code &ec)
{
    if (ec)
    {
        log_(0, FUNCTION, " error: ", ec.message());
        return;
    }
    // Do some stuff
}

void event_handler(odtone::mih::message &msg, const boost::system::error_code &ec)
{
    if (ec)
    {
        log_(0, FUNCTION, " error: ", ec.message());
        return;
    }

switch (msg.mid())
{
    // Destination Cloud Server received HO Commit Message
    case odtone::mih::indication::n2n_ho_commit:
    {
        boost::thread thrd(boost::bind(&handover_request_handler,  msg, ec));
        thrd.join();
    }
    break;
     }

}

When I try to compile it using b2 tool, I get the following errors:

gcc.compile.c++ ../../bin.v2/app/lte_mih_usr/gcc-4.6/debug/link-static/runtime-link-static/main.o main.cpp: In function ‘void event_handler(odtone::mih::message&, const boost::system::error_code&)’: main.cpp:189:69: error: use of deleted function ‘odtone::mih::message::message(const odtone::mih::message&)’ In file included from ../../inc/odtone/mih/request.hpp:24:0, from main.cpp:11:

So how to solve this problem?

Thanks a lot.

回答1:

The thread constructor copies its arguments, and the message type is not copyable. To pass a reference to the target function you need to use boost::ref(msg)

Also note that using bind with thread is unnecessary:

boost::thread thrd(&handover_request_handler, boost::ref(msg), boost::ref(ec));

The thread constructor implements the same semantics as bind, so using bind just adds unnecessary additional copying.