在调用函数 syslog ，则应调用 openlog 并指定"syslog标记".在此框架下，消息将被标记，您可以使用系统记录器(rsyslog，syslog-ng等)将这些消息发送到特定的日志文件，将它们发送到特定的日志服务器，发送紧急消息的电子邮件，等

Before calling the function syslog, you should call openlog and specify the "syslog tag". With this framework, the messages are tagged and you can use the system logger (rsyslog, syslog-ng, etc.) to send these messages to a specific log file, send them to a specific log server, send an email for emergency messages, etc.

此博客文章将syslog用于您的php应用程序".详细介绍了如何设置整个程序.

This blog post "Using syslog for your php applications" gives more details on how to setup the whole thing.