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



NAME
     sigprocmask - examine and change blocked signals

SYNOPSIS
     #include <signal.h>

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

DESCRIPTION
     sigprocmask allows the calling process to examine or change
     (or both) its signal mask.  If set is not NULL, it points to
     a set of signals to be used to change the currently blocked
     set.

     how indicates what effect set has on the signal mask.  how
     can have one of the following values:

     SIGBLOCK           The new signal mask is the union of the
                         current set and the signal set indicated
                         by set.

     SIGUNBLOCK         The new signal mask is the intersection
                         of the current set and the complement of
                         the signal set indicated by set.

     SIGSETMASK         The new signal mask is the signal set
                         indicated by set.

     If oset is not NULL, the previous mask is stored at the
     location indicated by oset.  If set is NULL, how is not sig-
     nificant and the process' signal mask is unchanged by the
     call.  A process can enquire about the currently blocked
     signals by setting set to NULL.

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

     SIGKILL and SIGSTOP cannot be blocked.  This restriction is
     silently enforced.

     If any of the SIGFPE, SIGILL, or SIGSEGV signals are gen-
     erated while they are blocked, the result is undefined,
     unless the signal was generated by a call to kill.

RETURN VALUES
     Upon successful completion, 0 is returned.  Otherwise, -1 is
     returned and errno is set to indicate the error.





                         Printed 1/15/91                   Page 1

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



ERRORS
     If any of the following conditions occur, sigprocmask
     returns -1 and sets errno to the corresponding value:

     [EINVAL]            how is not one of the defined values.

     [EFAULT]            set or oset points outside the process'
                         allocated address space.

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

SEE ALSO
     sigaction(2), sigpending(2), sigsetops(2), sigsuspend(2).









































 Page 2                  Printed 1/15/91