Question

I have a pthread that runs in a loop, calling accept() in a blocking manner. Is there any way to interrupt that call from another thread? Everything points to sending the thread a signal, but apparently you can only send a process a signal.

I can’t just kill the thread because then it leaves the socket open. And that’s not very clean anyway. Is there really no way to do this?

Answer 1

You can signal a thread using pthread_kill(3).

The pthread_kill() function sends the signal sig to thread, another
thread in the same process as the caller.

If a signal handler is installed, the handler will be invoked in the
thread thread.

Note, you don’t have to kill the thread; you can send a signal that simply makes accept fail with EINTR.