How to leave (interrupt) the waitpid() function?

Question

Currently I am programming a shell and I use the waitpid() function for my children processes.

I also installed a signal handler so I can trap the SIGINT (CTRL+C) signal.

So what I want now is when someone presses the SIGINT (CTRL+C) signal it should leave the waitpid() functions and keep going as usually.

I am looking for a function who can help me about that.

Answer 1

Install your signal handler without the SA_RESTART flag:

void handler( int sig, siginfo_t *si, void *arg )
{
    ...
}

...

struct sigaction newact;
memset( &newact, 0, sizeof( newact ) );
sigemptyset( &newact.sa_mask );
newact.sa_flags = SA_SIGINFO;  // note that **lack** of SA_RESTART
newact.sa_siginfo = handler;

sigaction( SIGINT, &newact, NULL );

You'll have to add error checking to that, and note that you will now have to handle interrupted calls in your code.