(PHP 4, PHP 5)
openlog — Open connection to system logger
说明bool openlog ( string $ident , int $option , int $facility )
openlog() opens a connection to the system logger for a program.
The use of openlog() is optional. It will automatically be called by syslog() if necessary, in which case ident will default to FALSE.
The string ident is added to each message.
The option argument is used to indicate what logging options will be used when generating a log message.
openlog() Options Constant Description 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
The facility argument is used to specify what type of program is logging the message. This allows you to specify (in your machine's syslog configuration) how messages coming from different facilities will be handled.
openlog() Facilities Constant Description 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
LOG_USER is the only valid log type under Windows operating systems
成功时返回 TRUE， 或者在失败时返回 FALSE.