SIGCHLD

Signal 20. Automatically called when a child exits.

Example Signal Handler

void sigchld_handler(int sig) {
  // Use waitpid() with WNOHANG to reap children
  int status;
  int pid;
  while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
    if (WIFEXITED(status)) write(2,"reaped\n", 7);
    else perror("statusexit\n");
  } 
}