Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
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:

       EAGAIN	       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.

       EINVAL	       The value of signo is an	invalid	or unsupported	signal

       ENOSYS	       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	   |
       |Interface Stability	     |Standard			   |
       |MT-Level		     |Async-Signal-Safe		   |

       kill(2),	 siginfo.h(3HEAD),  signal.h(3HEAD),   sigwaitinfo(3RT),   at-
       tributes(5), standards(5)

SunOS 5.10			  28 Jun 2002			 sigqueue(3RT)


Want to link to this manual page? Use this URL:

home | help