/* * See how many realtime signals we can queue. */#include	"unpipc.h"static void	sig_rt(int, siginfo_t *, void *);intmain(int argc, char **argv){	int		j;	pid_t	pid;	sigset_t	newset, oldset;	union sigval	val;	if ( (pid = Fork()) == 0) {			/* 4block all signals except SIGALRM */		Sigfillset(&newset);		Sigdelset(&newset, SIGALRM);		Sigprocmask(SIG_SETMASK, &newset, &oldset);			/* establish signal handler with SA_SIGINFO set */		Signal_rt(SIGRTMIN, sig_rt);		sleep(6);		/* let parent send all the signals */		Sigprocmask(SIG_SETMASK, &oldset, NULL);	/* unblock */		sleep(3);		/* let all queued signals be delivered */		exit(0);	}	sleep(3);		/* let child block all signals */		/* 4parent sends signals to child */	for (j = 0; j <= 1000000; j++) {		val.sival_int = j;		Sigqueue(pid, SIGRTMIN, val);		/* this should fail, eventually */		printf("sent SIGRTMIN (%ld), val = %d\n", (long) SIGRTMIN, j);	}	Waitpid(pid, NULL, 0);		/* wait for child */	exit(0);}static voidsig_rt(int signo, siginfo_t *info, void *context){	printf("received signal #%d, code = %d, ival = %d\n",		   signo, info->si_code, info->si_value.sival_int);}