#include <signal.h>
int sigqueue(
pid_t pid,
int signo,
const union sigval value
);
STATUS CODES:
EAGAIN
No resources available to queue the signal. The process has already
queued SIGQUEUE_MAX signals that are still pending at the receiver
or the systemwide resource limit has been exceeded.
EINVAL
The value of the signo argument is an invalid or unsupported signal
number.
EPERM
The process does not have the appropriate privilege to send the signal
to the receiving process.
RTEMS POSIX API User's Guide