PHP 手冊
前一頁 | 章 21. References Explained | 下一頁

# Spotting References

Many syntax constructs in PHP are implemented via referencing mechanisms, so everything told above about reference binding also apply to these constructs. Some constructs, like passing and returning by-reference, are mentioned above. Other constructs that use references are:

## global References

When you declare variable as global $var you are in fact creating reference to a global variable. That means, this is the same as:

`<?php $var =& $GLOBALS["var"]; ?>`

That means, for example, that unsetting $var won't unset global variable.

## $this

In an object method, $this is always reference to the caller object.

前一頁 | 內容 | 下一頁
Unsetting References | 上一層 | 安全性