/* Test ignoring, blocking, and raising SIGUSR1. */ #include "signal.h" int main(void) { sigset_t sigusr1; sigemptyset(&sigusr1); sigaddset(&sigusr1, SIGUSR1); sigprocmask(SIG_BLOCK, &sigusr1, NULL); signal(SIGUSR1, SIG_IGN); raise(SIGUSR1); return 0; }