No external libraries are needed to build this extension.
There is no installation needed to use these functions; they are part of the PHP core.
The behaviour of these functions is affected by settings in php.ini.
Table 1. Network Configuration Options
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 define_syslog_variables().
This extension has no resource types defined.
The constants below are always available as part of the PHP core.
Table 2. openlog() Options
Table 3. openlog() Facilities
Table 4. syslog() Priorities (in descending order)
Table 5. dns_get_record() Options