sigemptyset(), sigfillset(), sigaddset(), sigdelset(), sigismember() - manipulate signal sets
#include <signal.h>
int sigemptyset (sigset_t *set)
int sigfillset (sigset_t *set)
int sigaddset (sigset_t *set, int signo)
int sigdelset (sigset_t *set, int signo)
int sigismember (sigset_t *set, int signo)
These functions manipulate signal sets stored in a sigset_t. You must call either sigemptyset(3) or sigfillset(3) for every object of type sigset_t before any other use of the object.
The sigemptyset(3) function initializes a signal set to be empty of the POSIX signals.
The sigfillset(3) function initializes a signal set to contain all of the POSIX signals.
The sigaddset(3) function adds the specified signal signo to the signal set.
The sigdelset(3) function deletes the specified signal signo from the signal set.
The sigismember(3) function returns whether a specified signal signo is contained in the signal set.
These functions are provided as macros in the include file <signal.h>. Actual functions are available if their names are undefined (with #undef name
The sigismember(3) function returns 1 if the signal is a member of the set, 0 otherwise. The other functions return 0 upon successful completion; otherwise, they return -1 and set errno to indicate the error.
sigaddset(3), sigdelset(3), and sigismember(3) (that is, all execpt sigemptyset(3) and sigfillset(3)) may fail because:
kill(2)
sigaction(2)
sigprocmask(2)
sigsuspend(2)