PHP5中文手册·Returns the value of a constant -- 追寻梦想＞编程乐园＞PHP 编程

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

define()
defined()
The section on Constants


	PHP5中文手册 connection_timeout define 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 define() defined() The section on Constants connection_timeout define Misc. PHP Manual