#include "apue.h"#include <errno.h>voidpr_mask(const char *str){	sigset_t	sigset;	int			errno_save;	errno_save = errno;		/* we can be called by signal handlers */	if (sigprocmask(0, NULL, &sigset) < 0)		err_sys("sigprocmask error");	printf("%s", str);	if (sigismember(&sigset, SIGINT))   printf("SIGINT ");	if (sigismember(&sigset, SIGQUIT))  printf("SIGQUIT ");	if (sigismember(&sigset, SIGUSR1))  printf("SIGUSR1 ");	if (sigismember(&sigset, SIGALRM))  printf("SIGALRM ");	/* remaining signals can go here  */	printf("\n");	errno = errno_save;}