syslog()

syslog() — Generate a system log message.

Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

syslog() generates a log message that will be distributed by the system logger.

Signature

syslog(int $priority, string $message): true

Parameters

Parameter	Type	What it takes
$priority	int	One of the LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, LOG_DEBUG constants.
$message	string	The message to send.

Return value

Always returns true.

Example

A runnable snippet:

// open syslog, include the process ID and also send // the log to standard error, and use a user defined // logging mechanism openlog("myScriptLog", LOG_PID | LOG_PERROR, LOG_LOCAL0); // some code if (authorized_client()) { // do something } else { // unauthorized client! // log the attempt $access = date("Y/m/d H:i:s"); syslog(LOG_WARNING, "Unauthorized client: $access {$_SERVER['REMOTE_ADDR']} ({$_SERVER['HTTP_USER_AGENT']})"); } closelog();