#include
static void sig_usr(int);int main(void){ if (signal(SIGUSR1, sig_usr) == SIG_ERR) { printf("can't catch SIGUSR1\n"); return 1; } if (signal(SIGUSR2, sig_usr) == SIG_ERR) { printf("can't catch SIGUSR2\n"); return 2; } while(1) { pause(); }}static void sig_usr(int signo){ if (signo == SIGUSR1) { printf("received SIGUSR1\n"); } else if (signo == SIGUSR2) { printf("received SIGUSR2\n"); } else { printf("received signal %d\n", signo); } return;}