Originální popis anglicky:
sigqueue - queue a signal and data to a process
Návod, kniha: Linux Programmer's Manual
#include <signal.h>
int sigqueue(pid_t pid, int sig, const union
sigval value);
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
(either 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 argument to the handler. Furthermore, the
si_code field of that
structure will be set to
SI_QUEUE.
On success,
sigqueue() returns 0, indicating that the signal was
successfully queued to the receiving proces. Otherwise -1 is returned and
errno is set to indicate the error.
- EAGAIN
- The limit of signals which may be queued has been reached.
(See signal(7) for further information.)
- EINVAL
- sig was invalid.
- EPERM
- The process does not have permission to send the signal to
the receiving process. For the required permissions, see
kill(2).
- ESRCH
- No process has a PID matching pid.
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 returns.
POSIX 1003.1-2001
kill(2),
sigaction(2),
signal(2),
sigwait(3),
signal(7)
