int
pthread_sigmask(
int how
, const sigset_t * restrict set
, sigset_t * restrict oset
)
)
function examines and/or changes the calling thread's signal mask.
If
set
is not
NULL
,
it specifies a set of signals to be modified, and
how
specifies what to set the signal mask to:
SIG_BLOCK
set
.
SIG_UNBLOCK
set
.
SIG_SETMASK
set
.
If
oset
is not NULL, the previous signal mask is stored in the location pointed to by
oset
.
SIGKILL
and
SIGSTOP
cannot be blocked, and will be silently ignored if included in the signal mask.
)
returns 0.
Otherwise, an error is returned.
)
shall fail if:
EINVAL
]
how
is not one of the defined values.
)
conforms to
ISO/IEC 9945-1:1996 (``POSIX.1'')