[zeromq-dev] blocking zmq_close?

[Whitney Jackson]

Hi,

I'm using the ZMQ_FD getsockopt feature to integrate ZeroMQ into an
event loop that I don't control and don't have the source code for.
This works quite well except when I want to close a ZeroMQ socket.
Since zmq_close is non-blocking, control gets returned to the event
loop before the socket is fully shutdown causing this error:

Bad file descriptor (epoll.cpp:69)

gdb on the core file shows

#0  0xf77bf430 in __kernel_vsyscall ()
#1  0x45d7395f in raise () from /lib/libc.so.6
#2  0x45d752b3 in abort () from /lib/libc.so.6
#3  0xf36f719c in zmq::zmq_abort (errmsg_=0x45eaf393 "Bad file
descriptor") at err.cpp:76
#4  0xf36f5f0a in zmq::epoll_t::add_fd (this=0x9029a10, fd_=14,
events_=0x902a2b0) at epoll.cpp:69
#5  0xf370c3d7 in zmq::socket_base_t::start_reaping (this=0x902a210,
poller_=0x9029a10) at socket_base.cpp:717
#6  0xf3705a87 in zmq::reaper_t::process_reap (this=0x90287e0,
socket_=0x902a210) at reaper.cpp:101
#7  0xf36fbfd4 in zmq::object_t::process_command (this=0x90287e0,
cmd_=...) at object.cpp:120
#8  0xf370591f in zmq::reaper_t::in_event (this=0x90287e0) at reaper.cpp:72
#9  0xf36f64f7 in zmq::epoll_t::loop (this=0x9029a10) at epoll.cpp:161
#10 0xf36f65c5 in zmq::epoll_t::worker_routine (arg_=0x9029a10) at epoll.cpp:174
#11 0xf3710792 in thread_routine (arg_=0x9029a54) at thread.cpp:75
#12 0xf7749adf in start_thread () from /lib/libpthread.so.0
#13 0x45e3655e in clone () from /lib/libc.so.6

I can prevent the error by doing a zmq_term on the context or just
sleeping before returning control to the event loop but obviously
these solutions aren't optimal.

Is there some way to block until zmq_close is really done?

Whitney