Question

These two functions are both infinite loops,

and the programe hangs once called in the same thread.

gtk_main(); 
...
pcap_loop(adhandle, 0, packet_handler, NULL);

When I click the “start” button,I want pcap to start working;And if I press the “stop” button,pcap stop.

How do I create a child thread and run pcap_loop(adhandle, 0, packet_handler, NULL); instead?

Answer 1

Unless I am missing something, your problem is that both GTK+ and
libpcap are organized around events fired from a main loop. Without
looking through the documentation, I don’t know about GTK+, but there
is another mode of operation for libpcap: You can use pcap_next() or
pcap_next_ex() without giving up control over your program flow.

It should be possible to register a function that periodically calls
one of these two functions using g_timeout_add() or g_idle_add(),
removing the need to mess around with threads and mutex mechanisms
altogether.