(PHP 7 >= 7.1.0)
pcntl_async_signals — Enable/disable asynchronous signal handling or return the old setting
$on = NULL
] ) : bool
If the on parameter is omitted,
pcntl_async_signals() returns whether asynchronous signal
handling is enabled. Otherwise, asynchronous signal handling is enabled or
disabled.
onWhether asynchronous signal handling should be enabled.
When used as getter (that is without the optional parameter) it returns whether asynchronous signal handling is enabled. When used as setter (that is with the optional parameter given), it returns whether asynchronous signal handling was enabled before the function call.