sigdelset(3)                                               sigdelset(3)

  sigsetops()

  NAME

    sigemptyset(), sigfillset(), sigaddset(), sigdelset(), sigismember() -
    manipulate signal sets

  SYNOPSIS

    #include 

    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)

  DESCRIPTION

    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 .
    Actual functions are available if their names are undefined (with #undef
    name

  RETURN VALUES

    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.

  ERRORS

    sigaddset(3), sigdelset(3), and sigismember(3) (that is, all execpt
    sigemptyset(3) and sigfillset(3)) may fail because:

    [EINVAL]
        The specified signo is invalid.

  SEE ALSO

    kill(2)

    sigaction(2)

    sigprocmask(2)

    sigsuspend(2)

  USAGE NOTES

    All of these functions are thread safe.

    The following functions are async-signal safe: sigaddset, sigdelset,
    sigemptyset, sigfillset, sigismember. The sigsetops function is not async-
    signal safe.