SIGPROCMASK(2-SVR4) RISC/os Reference Manual  SIGPROCMASK(2-SVR4)



NAME
     sigprocmask - change or examine signal mask

SYNOPSIS
     #include <signal.h>

     int sigprocmask(int how, const sigsett *set, sigsett
     *oset);

DESCRIPTION
     The sigprocmask function is used to examine and/or change
     the calling process's signal mask.  If the value is
     SIG_BLOCK, the set pointed to by the argument set is added
     to the current signal mask.  If the value is SIG_UNBLOCK,
     the set pointed by the argument set is removed from the
     current signal mask.  If the value is SIG_SETMASK, the
     current signal mask is replaced by the set pointed to by the
     argument set.  If the argument oset is not NULL, the previ-
     ous mask is stored in the space pointed to by oset.  If the
     value of the argument set is NULL, the value how is not sig-
     nificant and the process's signal mask is unchanged; thus,
     the call can be used to enquire about currently blocked sig-
     nals.

     If there are any pending unblocked signals after the call to
     sigprocmask, at least one of those signals will be delivered
     before the call to sigprocmask returns.

     It is not possible to block those signals that cannot be
     ignored [see sigaction(2)]; this restriction is silently
     imposed by the system.

     If sigprocmask fails, the process's signal mask is not
     changed.

     sigprocmask fails if any of the following is true:

     EINVAL         The value of the how argument is not equal to
                    one of the defined values.

     EFAULT         The value of set or oset points outside the
                    process's allocated address space.

SEE ALSO
     sigaction(2), signal(2), sigsetopts(3C), signal(5).

DIAGNOSTICS
     On success, sigprocmask returns zero.  On failure, it
     returns -1 and sets errno to indicate the error.






                        Printed 11/19/92                   Page 1