SIGPROCMASK(2) | System Calls Manual | SIGPROCMASK(2) |
sigprocmask
—
manipulate current signal mask
#include
<signal.h>
int
sigprocmask
(int how,
const sigset_t *restrict set, sigset_t
*restrict oset);
The
sigprocmask
()
function examines and/or changes the current signal mask (those signals that
are blocked from delivery). Signals are blocked if they are members of the
current signal mask set.
If set is not null, the
action of
sigprocmask
()
depends on the value of the parameter how. The signal
mask is changed as a function of the specified set and
the current mask. The function is specified by how
using one of the following values from
⟨signal.h⟩:
SIG_BLOCK
SIG_UNBLOCK
SIG_SETMASK
If oset is not null, it is set to the previous value of the signal mask. When set is null, the value of how is insignificant and the mask remains unset providing a way to examine the signal mask without modification.
The system quietly disallows SIGKILL
or
SIGSTOP
to be blocked.
A 0 value indicated that the call succeeded. A -1 return value indicates an error occurred and errno is set to indicated the reason.
The sigprocmask
() call will fail and the
signal mask will be unchanged if one of the following occurs:
EINVAL
]The sigprocmask
() function call is
expected to conform to IEEE Std 1003.1-1988
(“POSIX.1”).
June 4, 1993 | macOS 14.6 |