更新时间:2023-11-27 23:30:40
首先,这些不是变量,而是常量.
First, these are not variables, but constants.
您可以使用 defined()
函数检查它们的存在:
And you can check their existence by using the defined()
function :
bool defined ( string $name )
检查给定常量是否存在并已定义.
Checks whether the given constant exists and is defined.