The behaviour of these functions is affected by settings in php.ini.
Network Configuration Options
For further details and definitions of the
PHP_INI_* constants, see the php.ini directives
Here's a short explanation of
the configuration directives.
Whether or not to define the various syslog variables (e.g. $LOG_PID,
$LOG_CRON, etc.). Turning it off is a good idea performance-wise. At
runtime, you can define these variables by calling