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SIGQUEUE(2)		   Linux Programmer's Manual		   SIGQUEUE(2)

NAME
       sigqueue	- queue	a signal and data to a process

SYNOPSIS
       #include	<signal.h>

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

DESCRIPTION
       sigqueue()  sends  the signal specified in sig to the process whose PID
       is given	in pid.	 The permissions required to send  a  signal  are  the
       same  as	for kill(2).  As with kill(2), the null	signal (0) can be used
       to check	if a process with a given PID exists.

       The value argument is used to specify an	accompanying item of data (ei-
       ther an integer or a pointer value) to be sent with the signal, and has
       the following type:

	 union sigval {
	     int   sival_int;
	     void *sival_ptr;
	 };

       If the receiving	process	has installed a	handler	for this signal	 using
       the  SA_SIGINFO	flag to	sigaction(2), then it can obtain this data via
       the si_value field of the siginfo_t structure passed as the second  ar-
       gument  to  the handler.	 Furthermore, the si_code field	of that	struc-
       ture will be set	to SI_QUEUE.

RETURN VALUE
       On success, sigqueue() returns 0, indicating that the signal  was  suc-
       cessfully queued	to the receiving proces.  Otherwise -1 is returned and
       errno is	set to indicate	the error.

ERRORS
       EAGAIN The limit	of signals which may be	queued has been	reached.  (See
	      signal(7)	for further information.)

       EINVAL sig was invalid.

       ESRCH  No process has a PID matching pid.

       EPERM  The  process  does not have permission to	send the signal	to the
	      receiving	process.  (See kill(2) for further information.)

NOTES
       If this function	results	in the sending of a signal to the process that
       invoked	it, and	that signal was	not blocked by the calling thread, and
       no other	threads	were willing to	handle this signal (either  by	having
       it  unblocked,  or  by  waiting for it using sigwait(3)), then at least
       some signal must	be delivered to	this thread before this	 function  re-
       turns.

CONFORMING TO
       POSIX 1003.1-2001

SEE ALSO
       kill(2),	sigaction(2), signal(2), sigwait(3), signal(7)

Linux 2.4.18			  2002-06-07			   SIGQUEUE(2)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | NOTES | CONFORMING TO | SEE ALSO

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