sigqueueinfo(2) [netbsd man page]

SIGQUEUE(2)						      BSD System Calls Manual						       SIGQUEUE(2)

NAME

     sigqueue -- queue a signal to a process (REALTIME)

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <signal.h>

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

     int
     sigqueueinfo(pid_t pid, const siginfo_t *info);

DESCRIPTION

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

     The conditions required for a process to have permission to queue a signal to another process are the same as for the kill(2) system call.
     The sigqueue() system call queues a signal to a single process specified by the pid argument.

     The sigqueue() system call is implemented using sigqueueinfo() and passing the appropriate information in the info argument.

     The sigqueue() system call returns immediately.  If the resources were available to queue the signal, the signal will be queued and sent to
     the receiving process.

     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() system call for signo, either signo or at least the pending, unblocked signal will be
     delivered to the calling thread before sigqueue() returns.  Should any multiple pending signals in the range SIGRTMIN to SIGRTMAX be selected
     for delivery, it is the lowest numbered one.  The selection order between realtime and non-realtime signals, or between multiple pending non-
     realtime signals, is unspecified.

RETURN VALUES

     Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS

     The sigqueue() system call 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.

     [EEPERM]		The process does not have the appropriate privilege to send the signal to the receiving process.

     [EINVAL]		The value of the signo argument is an invalid or unsupported signal number.

     [ESRCH]		The process pid does not exist.

SEE ALSO

     sigaction(2), siginfo(2), sigpending(2), sigsuspend(2), sigtimedwait(2), sigwait(2), sigwaitinfo(2), pause(3), pthread_sigmask(3)

STANDARDS

     The sigqueue() system call conforms to IEEE Std 1003.1-2004 (``POSIX.1'').

HISTORY

     Support for POSIX realtime signal queue first appeared in NetBSD 6.0.

BSD
								  January 9, 2011							       BSD

Check Out this Related Man Page

sigqueue(3)						     Library Functions Manual						       sigqueue(3)

NAME

       sigqueue -  Queues a signal and data to a running process

LIBRARY

       Realtime Library (librt.so, librt.a)

SYNOPSIS

       #include <signal.h>

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

PARAMETERS

       pid     Specifies the ID of the target process.

       signo   Specifies  the  signal  to  be  queued. If the signo parameter is 0 (the null signal), error checking is performed but no signal is
	       sent. This can be used to check the validity of the pid parameter.

       value   Specifies the application-defined value to be queued to the receiving process.

DESCRIPTION

       The sigqueue function causes the signal specified by signo to be sent with the value specified by value to the process specified by pid.

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

       If the call is successful, the signal is queued to the specified process. If the process has the SA_SIGINFO flag  enabled  for  the  queued
       signal,	the  specified	value is delivered to its signal handler as the si_value field of the siginfo parameter. Nonprivileged callers are
       restricted  in  the  number  of	signals  they  can  have  actively  queued.  This  per-process	quota	value	can   be   returned   with
       sysconf(_SC_SIGQUEUE_MAX).

RETURN VALUES

       Upon  successful  completion,  the  sigqueue function returns a value of 0 (zero). Otherwise, a value of -1 is returned and errno is set to
       indicate the error.

ERRORS

       If sigqueue fails, no signal is sent, and errno is set to one of the following values:

       [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 signo parameter is not a valid signal number.

       [EINVAL]       The signo parameter is SIGKILL, SIGSTOP, SIGTSTP, or SIGCONT, and the pid parameter is 1 (process 1 -- init).

       [ESRCH]	      No process can be found corresponding to that specified by the pid parameter.

       [EPERM]	      The  real  or  saved user ID does not match the real or effective user ID of the receiving process, the calling process does
		      not have appropriate privilege, or the process is not sending a SIGCONT signal to one of its session's processes.

RELATED INFORMATION

       Headers: siginfo(5)

       Functions: kill(2), sigaction(2), sysconf(3)

       Guide to Realtime Programming delim off

																       sigqueue(3)

Linux and UNIX Man Pages

sigqueueinfo(2) [netbsd man page]

Check Out this Related Man Page