PHP Manual: pcntl_sigprocmask

function pcntl_sigprocmask(int $mode, array $signals, array &$old_signals = null): bool

The pcntl_sigprocmask() function adds, removes or sets blocked signals, depending on the mode parameter.

mode

Sets the behavior of pcntl_sigprocmask(). Possible values:

SIG_BLOCK: Add the signals to the currently blocked signals.
SIG_UNBLOCK: Remove the signals from the currently blocked signals.
SIG_SETMASK: Replace the currently blocked signals by the given list of signals.

signals

List of signals.

old_signals

The old_signals parameter is set to an array containing the list of the previously blocked signals.

Returns true on success or false on failure.

Version	Description
8.4.0	A ValueError is thrown if `signals` is empty, unless `mode` is `SIG_SETMASK`.
8.4.0	A TypeError is thrown if `signals` value is not an int.
8.4.0	A ValueError is thrown if `signals` value is invalid.
8.4.0	A ValueError is thrown if `mode` value is not `SIG_BLOCK`, `SIG_UNBLOCK` or `SIG_SETMASK`.

Example #1 pcntl_sigprocmask() example

<?php
pcntl_sigprocmask(SIG_BLOCK, array(SIGHUP));
$oldset = array();
pcntl_sigprocmask(SIG_UNBLOCK, array(SIGHUP), $oldset);
?>

pcntl_sigprocmask