Valgrind disagree with pop_front() on received zmqpp::message
pavel-orekhov opened this issue · 2 comments
When I call pop_front() on message after sock.receive() valgrind starts to worry.
I use 4.2.0+ version at intel64 (ubuntu 17.10)
Please confirm the bug.
commit 818f9c3 (HEAD -> develop, origin/develop, origin/HEAD)
Author: Ben Gray ben@benjamg.com
Date: Fri Nov 3 11:29:06 2017 +0000
shifted tests to use last_endpoint to avoid port collisions (#203)
commit f8ff127 (tag: 4.2.0)
A sample is here:
popfront.cpp.txt
I found a sentence:
If you do use zmq_msg_recv(), always release the received message as soon as you're done with it, by calling zmq_msg_close().
Queue to check it with pop_front()
The problem here is a bug in the move assignment operator of the frame class.
frame& frame::operator=(frame&& other)
{
zmq_msg_init( &_msg ); <-- this line needs to go
zmq_msg_move( &_msg, &other._msg );
std::swap( _sent, other._sent );
return *this;
}
The call to zmq_msg_init() at the beginning clears the zmq_msg_t object without closing it. Since zmq_msg_move() does that closing on the supplied _msg the solution is simple: just remove the zmq_msg_init() line.
Btw, the reason why valgrind is complaining about message::pop_front() is that this method erases the first element of the message from a std::vector<frame>. When doing this the vector needs to move all remaining frames thereby leaking memory for each of them.