PHP openlog() Function

The PHP openlog() function opens the connection to system logger. The use of openlog() is optional. It will automatically be called by syslog() if necessary, in that case prefix will default to false.

Syntax

openlog(prefix, flags, facility)

Parameters

`prefix`	`Required.` Specify the string prefix is added to each message.
`flags`	`Required.` Specify what logging options will be used when generating a log message. Possible values are: LOG_CONS - if there is an error while sending data to the system logger, write directly to the system console LOG_NDELAY - open the connection to the logger immediately LOG_ODELAY - (default) delay opening the connection until the first message is logged LOG_PERROR - print log message also to standard error LOG_PID - include PID with each message one or more of these options can be used. For multiple options OR (\|) is used. For example - to open the connection immediately, write to the console and include the PID in each message, the flags will be: LOG_CONS \| LOG_NDELAY \| LOG_PID
`facility`	`Required.` Specify what type of program is logging the message. This allows to specify how messages coming from different facilities will be handled. Possible values are: LOG_AUTH - security/authorization messages (use LOG_AUTHPRIV instead in systems where that constant is defined) LOG_AUTHPRIV - security/authorization messages (private) LOG_CRON - clock daemon (cron and at) LOG_DAEMON - other system daemons LOG_KERN - kernel messages LOG_LOCAL0 ... LOG_LOCAL7 -reserved for local use, these are not available in Windows LOG_LPR -line printer subsystem LOG_MAIL - mail subsystem LOG_NEWS - USENET news subsystem LOG_SYSLOG - messages generated internally by syslogd LOG_USER - generic user-level messages LOG_UUCP - UUCP subsystem Note: LOG_USER is the only valid log type under Windows operating systems

Return Value

Returns true on success or false on failure.

Example:

The example below shows the usage of openlog() function.

<?php
//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);

//code lines

if (authorized_client()) {
  //code lines
} else {
  //unauthorized client! - attempt to log
  $access = date("Y/m/d H:i:s");
  syslog(LOG_WARNING, 
         "Unauthorized client: $access {$_SERVER['REMOTE_ADDR']} ({$_SERVER['HTTP_USER_AGENT']})");
}

//closing the system logger
closelog();
?>

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