Misc.
PHP Manual

constant

(PHP 4 >= 4.0.4, PHP 5)

constant — Returns the value of a constant

说明

mixed constant ( string $name )

Return the value of the constant indicated by name .

constant() is useful if you need to retrieve the value of a constant, but do not know its name. I.e. it is stored in a variable or returned by a function.

This function works also with class constants.

参数

name

The constant name.

返回值

Returns the value of the constant, or NULL if the constant is not defined.

范例

Example#1 constant() example

<?php

define
("MAXSIZE"100);

echo 
MAXSIZE;
echo 
constant("MAXSIZE"); // same thing as the previous line

?>

参见


Misc.
PHP Manual