iOS – Ping with timeout

Apple sample code:

bytesSent = sendto(
    CFSocketGetNative(self->_socket),
    sock,
    [packet bytes],
    [packet length], 
    0, 
    (struct sockaddr *) [self.hostAddress bytes], 
    (socklen_t) [self.hostAddress length]
);

to change the timeout:

CFSocketNativeHandle sock = CFSocketGetNative(self->_socket);
struct timeval tv;
tv.tv_sec  = 0;
tv.tv_usec = 100000; // 0.1 sec
setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (void *)&tv, sizeof(tv));

bytesSent = sendto(
    sock,
    [packet bytes],
    [packet length], 
    0, 
    (struct sockaddr *) [self.hostAddress bytes], 
    (socklen_t) [self.hostAddress length]
);

See Apple’s docs: setsockopt

From the above referenced doc:

SO_SNDTIMEO is an option to set a timeout value for output operations. It accepts a struct timbal parameter with the number of seconds and microseconds used to limit waits for output operations to complete. If a send operation has blocked for this much time, it returns with a partial count or with the error EWOULDBLOCK if no data were sent. In the current implementation, this timer is restarted each time additional data are delivered to the protocol, implying that the limit applies to output portions ranging in size from the low-water mark to the high-water mark for output.