Index: phpdoc/en/functions/pcntl.xml
+++ phpdoc/en/functions/pcntl.xml
Process Control FunctionsPCNTL
Process Control support in PHP is not enabled by default. You
will need to use the --enable-pcntl
configuration option when compiling PHP to enable Process Control
support.
The following list of signals are supported by the Process Control
functions. Please see your systems signal(7) man page for details
of the default behavior of these signals.
Process Control Example
This example forks off a daemon process with a signal handler.
Process Control Example
<?php
$pid = pcntl_fork();
if ($pid == -1) {
die("could not fork");
} else if ($pid) {
exit(); // we are the parent
} else {
// we are the child
}
// detatch from the controlling terminal
if (!posix_setsid()) {
die("could not detach from terminal");
}
// setup signal handlers
pcntl_signal(SIGTERM, "sig_handler");
pcntl_signal(SIGHUP, "sig_handler");
// loop forever performing tasks
while(1) {
// do something interesting here
}
function sig_handler($signo) {
switch($signo) {
case SIGTERM:
// handle shutdown tasks
exit;
break;
case SIGHUP:
// handle restart tasks
break;
default:
// handle all other signals
}
}
?>
pcntl_forkForks the currently running processDescriptionint pcntl_fork
The pcntl_fork function creates a child
process that differs from the parent process only in it's PID and
PPID. Please see your system's fork(2) man page for specific details as to
how fork works on your system.
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.
See also pcntl_waitpid and
pcntl_signal.
pcntl_waitpidWaits on or returns the status of a forked childDescriptionint pcntl_waitpidint pidint statusint options
The pcntl_waitpid function suspends execution
of the current process until a child as specified by the
pid argument has exited, or until a signal
is delivered whose action is to terminate the current process or
to call a signal handling function. If a child as requested by
pid has already exited by the time of the
call (a so-called "zombie" process), the function returns
immediately. Any system resources used by the child are
freed. Please see your system's waitpid(2) man page for specific
details as to how waitpid works on your system.
pcntl_waitpid returns the process ID of the
child which exited, -1 on error or zero if WNOHANG was used and no
child was available
The value of pid can be one of the following:
< -1
wait for any child process whose process group ID is equal to
the absolute value of pid.
-1
wait for any child process; this is the same behaviour that
the wait function exhibits.
0
wait for any child process whose process group ID is equal to
that of the calling process.
> 0
wait for the child whose process ID is equal to the value of
pid.
pcntl_waitpid will store status information
in the status parameter which can be
evaluated using the following functions:
pcntl_wifexited,
pcntl_wifstopped,
pcntl_wifsignaled,
pcntl_wexitstatus,
pcntl_wtermsig and
pcntl_wstopsig.
The value of options is the value of zero
or more of the following two global constants
ORed together:
WNOHANG
return immediately if no child has exited.
WUNTRACED
return for children which are stopped, and whose status has
not been reported.
See also pcntl_fork,
pcntl_signal,
pcntl_wifexited,
pcntl_wifstopped,
pcntl_wifsignaled,
pcntl_wexitstatus,
pcntl_wtermsig and
pcntl_wstopsig.
pcntl_signalInstalls a signal handlerDescriptionbool pcntl_signalint signomixed handle
The pcntl_signal function installs a new
signal handler for the signal indicated by
signo. The signal handler is set to
handler which may be the name of a user
created function, or either of the two global constants SIG_IGN
or SIG_DFL.
pcntl_signal returns &true; on success or
&false; on failure.
See also pcntl_fork and
pcntl_waitpid.
