pcntl_rfork
Manipulates process resources
Description
int pcntl_rfork(int $flags, int $signal = 0)
Parameters
-
flags
-
The flags parameter determines which resources of the invoking process (parent)
are shared by the new process (child) or initialized to their default values.
flags is the logical OR of some subset of:
-
RFPROC: If set a new process is created;
otherwise changes affect the current process.
-
RFNOWAIT: If set, the child process will be dissociated from the parent.
Upon exit the child will not leave a status for the parent to collect.
-
RFFDG: If set, the invoker's file descriptor table is copied;
otherwise the two processes share a single table.
-
RFCFDG: If set, the new process starts with a clean file descriptor table.
Is mutually exclusive with RFFDG.
-
RFLINUXTHPN: If set, the kernel will return SIGUSR1 instead of SIGCHILD upon thread exit for the child.
This is intended to do Linux clone exit parent notification.
-
signal
-
The signal number.
Return Values
On success, the PID of the child process is returned in the
parent's thread of execution, and a 0 is returned in the child's
thread of execution.
On failure, a -1 will be returned in the
parent's context, no child process will be created, and a PHP error is raised.
Examples
Example #1 pcntl_rfork example
<?php
$pid = pcntl_rfork(RFNOWAIT|RFTSIGZMB, SIGUSR1);
if ($pid > 0) {
// This is the parent process.
var_dump($pid);
} else {
// This is the child process.
var_dump($pid);
sleep(2); // as the child does not wait, so we see its "pid"
}
?>
The above example will output
something similar to:
Notes
Note:
This function is only available on BSD systems.
See Also
- pcntl_fork
- pcntl_waitpid
- pcntl_signal
- cli_set_process_title