NAME

thr_sigsetmask − change and/or examine calling thread’s signal mask

SYNOPSIS

#include <thread.h>
#include <signal.h>

int thr_sigsetmask(int how, const sigset_t ∗set, sigset_t ∗oset);

MT-LEVEL

MT-Safe

DESCRIPTION

thr_sigsetmask() examines and/or changes the calling thread’s signal mask.  If the value of the argument set is not NULL, it points to a set of signals to be used to change the currently blocked set.  The value of the argument how determines the manner in which the set is changed.  how may have one of the following values:

SIG_BLOCK set represent a set of signals to block.  They are added to the current signal mask. 

SIG_UNBLOCK
set represents a set of signals to unblock.  These signals are deleted from the current signal mask. 

SIG_SETMASK
set represents the new signal mask.  The current signal mask is replaced by set.

If the value of oset is not NULL, it points to space where the previous signal mask is stored.  If the value of set is NULL, the value of how is not significant and the thread’s signal mask is unchanged; thus, thr_sigsetmask() can be used to enquire about the currently blocked signals. 

RETURN VALUES

Zero is returned when successful.  A non-zero value indicates an error. 

ERRORS

If any of the following conditions are detected, thr_sigsetmask() fails and returns the corresponding value:

EINVAL set is not NULL and the value of how is not defined. 

EFAULT set or oset are not valid addresses

SEE ALSO

sigaction(2), sigprocmask(2)

NOTES

It is not possible to block those signals that cannot be ignored (see sigaction(2)).  In addition, if using the threads library, it is not possible to block the signal SIGLWP, reserved by the threads library, and it is not possible to unblock the signal
SIGWAITING, which is always blocked on all threads. This restriction is silently imposed by the threads library. 

SunOS 5.4  —  Last change: 22 Jan 1993