System Calls                                       sigprocmask(2)



NAME
     sigprocmask - change or examine caller's signal mask

SYNOPSIS
     #include 

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


DESCRIPTION
     The sigprocmask() function is used to examine and/or  change
     the  caller's  signal  mask. If the value is  SIGBLOCK, the
     set pointed to by the  set argument is added to the  current
     signal  mask.  If the value is  SIGUNBLOCK, the set pointed
     by the  set argument is  removed  from  the  current  signal
     mask.  If the value is  SIGSETMASK, the current signal mask
     is replaced by the set pointed to by the  set  argument.  If
     the  oset argument is not  NUL, the previous mask is stored
     in the space pointed to by oset. If the value  of  the   set
     argument is  NUL, the value  how is not significant and the
     caller's signal mask is unchanged; thus,  the  call  can  be
     used  to inquire about currently blocked signals. If the set
     or oset argument points to an invalid address, the  behavior
     is undefined and errno may be set to EFAULT.


     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 signals that cannot be caught or
     ignored (see sigaction(2)). It is also not possible to block
     or unblock SIGCANCEL,  as  SIGCANCEL  is  reserved  for  the
     implementation    of    POSIX   thread   cancellation   (see
     pthreadcancel(3C) and cancellation(5)). This restriction is
     silently enforced by the standard C library.


     If sigprocmask() fails, the  caller's  signal  mask  is  not
     changed.

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

ERORS
     The sigprocmask() function will fail if:

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



SunOS 5.11          Last change: 23 Mar 2005                    1






System Calls                                       sigprocmask(2)



     The sigprocmask() function may fail if:

     EFAULT    The set or oset  argument  points  to  an  illegal
               address.


ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    
     MT-Level                     Async-Signal-Safe           
    


SEE ALSO
     sigaction(2),    pthreadcancel(3C),    pthreadsigmask(3C),
     signal(3C),  signal.h(3HEAD),  sigsetops(3C), attributes(5),
     cancellation(5)

NOTES
     The call to sigprocmask() affects only the calling  thread's
     signal    mask.    It    is   identical   to   a   call   to
     pthreadsigmask(3C).


     Signals that  are  generated  synchronously  should  not  be
     masked.  If  such  a  signal  is  blocked and delivered, the
     receiving process is killed.




















SunOS 5.11          Last change: 23 Mar 2005                    2