define Defines a named constant php函数


define

(PHP 4, PHP 5)

defineDefines a named constant

说明

bool define ( string $name , mixed $value [, bool $case_insensitive = false ] )

Defines a named constant at runtime.

参数

name

The name of the constant.

value

The value of the constant; only scalar and null values are allowed. Scalar values are integer, float, string or boolean values. It is possible to define resource constants, however it is not recommended and may cause unpredictable behavior.

case_insensitive

If set to TRUE, the constant will be defined case-insensitive. The default behavior is case-sensitive; i.e. CONSTANT and Constant represent different values.

Note:

Case-insensitive constants are stored as lower-case.

返回值

成功时返回 TRUE, 或者在失败时返回 FALSE.

范例

Example #1 Defining Constants

<?php
define
("CONSTANT""Hello world.");
echo 
CONSTANT// outputs "Hello world."
echo Constant// outputs "Constant" and issues a notice.

define("GREETING""Hello you."true);
echo 
GREETING// outputs "Hello you."
echo Greeting// outputs "Hello you."

?>

参见

  • defined() - Checks whether a given named constant exists
  • constant() - Returns the value of a constant
  • The section on Constants



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