sigsetops(3C)

sigsetops: sigemptyset, sigfillset, sigaddset, sigdelset, sigismember -- manipulate sets of signals

Synopsis

   #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 (const sigset_t set, int signo);

Description

sigemptyset- initialize empty signal set

sigfillset- initialize signal set to all signals

sigaddset- add to signal set

sigdelset- delete from signal set

sigismember- query signal set

These functions manipulate sigset_t data types, representing the set of signals supported by the implementation.

sigemptyset initializes the set pointed to by set to exclude all signals defined by the system.

sigfillset initializes the set pointed to by set to include all signals defined by the system.

sigaddset adds the individual signal specified by the value of signo to the set pointed to by set.

sigdelset deletes the individual signal specified by the value of signo from the set pointed to by set.

sigismember checks whether the signal specified by the value of signo is a member of the set pointed to by set.

Any object of type sigset_t must be initialized by applying either sigemptyset or sigfillset before applying any other operation.

Return values

Upon successful completion, the sigismember function returns a value of one if the specified signal is a member of the specified set, or a value of zero if it is not. Upon successful completion, the other functions return a value of zero. Otherwise a value of -1 is returned and errno is set to indicate the error.

Errors

In the following conditions, sigaddset, sigdelset and sigismember will fail and set errno to:

EINVAL: The value of the signo argument is not a valid signal number.

References

sigaction(2), signal(5), sigpending(2), sigprocmask(2), sigsuspend(2)