get pending signals
function returns a mask of the signals pending for delivery to the calling
process in the location indicated by set. Signals may
be pending because they are currently masked, or transiently before delivery
(although the latter case is not normally detectable).
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error.
sigpending() function does not
currently detect any errors.
sigaction(2), sigprocmask(2), sigaddset(3)
sigpending() function is defined by
IEEE Std 1003.1-2008 (“POSIX.1”).