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sigqueue(3RT)		  Realtime Library Functions		 sigqueue(3RT)

       sigqueue	- queue	a signal to a process

       cc [ flag... ] file... -lrt [ library...	]
       #include	<sys/types.h>
       #include	<signal.h>

       int sigqueue(pid_t pid, int signo, const	union sigval value);

       The sigqueue() function causes the signal specified by signo to be sent
       with the	value specified	by value to the	process	specified by  pid.  If
       signo is	0 (the null signal), error checking is performed but no	signal
       is actually sent. The null signal can be	used to	check the validity  of

       The  conditions	required  for  a process to have permission to queue a
       signal to another process are the same as for the kill(2) function.

       The sigqueue() function returns immediately. If SA_SIGINFO is  set  for
       signo and if the	resources were available to queue the signal, the sig-
       nal is queued and sent to the receiving process.	If SA_SIGINFO  is  not
       set  for	 signo,	 then  signo  is  sent	at least once to the receiving
       process;	it is unspecified whether value	will be	sent to	the  receiving
       process as a result of this call.

       If  the	value  of  pid	causes	signo  to be generated for the sending
       process,	and if signo is	not blocked for	the calling thread and	if  no
       other thread has	signo unblocked	or is waiting in a sigwait(2) function
       for signo, either signo or at least the pending,	unblocked signal  will
       be  delivered  to the calling thread before the sigqueue() function re-
       turns. Should any of multiple pending signals in	the range SIGRTMIN  to
       SIGRTMAX	 be selected for delivery, it will be the lowest numbered one.
       The selection order between realtime and	non-realtime signals,  or  be-
       tween multiple pending non-realtime signals, is unspecified.

       Upon successful completion, the specified signal	will have been queued,
       and the sigqueue() function returns  0. Otherwise, the function returns
       -1 and sets errno to indicate the error.

       The sigqueue() function will fail if:

	     No	 resources  are	available to queue the signal. The process has
	     already queued SIGQUEUE_MAX signals that are still	pending	at the
	     receiver(s), or a system wide resource limit has been exceeded.

	     The value of signo	is an invalid or unsupported signal number.

	     The sigqueue() function is	not supported by the system.

       EPERM The  process  does	not have the appropriate privilege to send the
	     signal to the receiving process.

       ESRCH The process pid does not exist.

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE	TYPE	     |	    ATTRIBUTE VALUE	   |
       |MT-Level		     |Async-Signal-Safe		   |

       kill(2),	sigwaitinfo(3RT), attributes(5), siginfo(3HEAD), signal(3HEAD)

SunOS 5.9			  22 Jun 1998			 sigqueue(3RT)


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