zmq_close hanging on unused socket

Description

Connecting to a non existent host, then calling zmq_close causes a block

Sample code:

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#include "zmq.h"

static bool keepRunning = true;

void sig_handler(int signo) {
        keepRunning = false;
}

int main ( int argc, char *argv[] )
{
        if (signal(SIGINT, sig_handler) == SIG_ERR)  printf("\ncan't catch SIGINT\n");

        void *context = zmq_ctx_new ();
        void *sender = zmq_socket (context, ZMQ_PUSH);
        uint64_t linger = 0;
        zmq_setsockopt( sender , ZMQ_LINGER, &linger, sizeof(linger));
        int rc = zmq_connect (sender, "tcp://8.8.8.8:2120");

        if (rc == -1) {
                printf ("E: bind failed: %s\n", strerror (errno));
                return -1;
        }

        while(keepRunning) {
                printf("Send message\n");
                zmq_send (sender, "test", 4, 0);
                sleep(1);
        }

        printf("Shutting down...\n");

        zmq_close (sender);
        printf("Closed\n");
        zmq_ctx_destroy (context);

        return 0;
}

Where IP 8.8.8.8 is used to demonstrate a host blocking connections on port 2120.

Compiled like so:

gcc -Wall -o test -lzmq test.c

When I run this, I get the following output:

# ./test
Send message
Send message
Send message
Send message
Send message
^CShutting down...               <--- hit CTRL+C here
Closed
                                             <---- blocking

Environment

Centos Linux 6.4, 64bit
kernel 2.6.32
glibc-2.12-1
libstdc++-4.4.7
zeromq-3.2.3

Activity

Show:

Guido G. August 29, 2013 at 10:07 AM

Might well be that the SO_LINGER option only works on a valid connection.
Which in this case never will happen.

Will have a look.

Details

Assignee

Unassigned

Reporter

Ian

Affects versions

3.2.3

Priority

Major

Created June 20, 2013 at 3:00 PM

Updated August 29, 2013 at 10:07 AM

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