NAME    [Toc]    [Back]

       sigqueue - Queues a signal and data to a running process

SYNOPSIS    [Toc]    [Back]

       #include <signal.h>

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

LIBRARY    [Toc]    [Back]

       Realtime Library (librt.so, librt.a)

PARAMETERS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

       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
       option  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    [Toc]    [Back]

       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    [Toc]    [Back]

       If sigqueue fails, no signal is sent, and errno is set  to
       one of the following values: 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 signo parameter is not a valid signal number.
  The signo parameter is SIGKILL, SIGSTOP, SIGTSTP, or
       SIGCONT,  and  the pid parameter is 1 (process 1 -- init).
       No process can be found corresponding to that specified by
       the  pid  parameter.   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.

SEE ALSO    [Toc]    [Back]

       Headers: siginfo(5)

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

       Guide to Realtime Programming



                                                      sigqueue(3)