Initializing PHP’s Logging Facility - PHP

Thedefine_syslog_variables()function initializes the constants necessary for using theopenlog(),closelog(), andsyslog()functions. Its prototype follows:

void define_syslog_variables(void)

You need to execute this function before using any of the following logging functions.

Opening the Logging Connection

Theopenlog()function opens a connection to the platform’s system logger and sets the stage for the insertion of one or more messages into the system log by designating several parameters that will be used within the log context. Its prototype follows:

int openlog(string ident, int option, int facility)

Several parameters are supported, including the following:

ident: Identifies messages. It is added to the beginning of each entry. Typically this value is
set to the name of the program. Therefore, you might want to identify PHP-related messages such as “PHP” or “PHP5.”

option: Determines which logging options are used when generating the message. A list of available options is offered in Table 8-2. If more than one option is required, separate each option with a vertical bar. For example, you could specify three of the options like so:
LOG_ODELAY | LOG_PERROR| LOG_PID.

facility: Helps determine what category of program is logging the message. There are several categories, includingLOG_KERN,LOG_USER,LOG_MAIL,LOG_DAEMON,LOG_AUTH,LOG_LPR, andLOG_LOCALN,whereN is a value ranging between 0 and 7. Note that the designated facility determines the message destination. For example, designatingLOG_CRONresults in the submission of subsequent messages to thecronlog, whereas designatingLOG_USERresults in the transmission of messages to themessagesfile. Unless PHP is being used as a command-line interpreter, you’ll likely want to set this toLOG_USER. It’s common to useLOG_CRONwhen executing PHP scripts from acrontab.See the syslog documentation for more information about this matter.

Table 8-2. Logging Options  

Closing the Logging Connection

Thecloselog()function closes the connection opened byopenlog(). Its prototype follows:

int closelog(void)