Send and catch signals to pthreads in C

Question

I know how to send signals to child process in C using the kill(pid_t pid, int sig) function. What about sending signals to threads? is it possible?. If so, how to catch signals on the "child" thread. For example, if the main thread sends me a terminate signal, how can I in the other thread catch it.

Answer 1

With POSIX threads, you have the functions pthread_cond_wait and pthread_cond_signal.

int pthread_cond_wait(pthread_cond_t *restrict cond, pthread_mutex_t *restrict mutex)
int pthread_cond_signal(pthread_cond_t *cond)

The signaled thread should block on a pthread_cond_wait call until another thread sends a signal using pthread_cond_signal, with the same condition variable.

Considering the analogy with signals delivered to processes, this is a bit different because the signaled thread has already suspended its execution waiting for a signal, unlike a process that simply gets interrupted and goes on.