define

Defines a named constant (PHP 3, PHP 4, PHP 5)
bool define ( string name, mixed value [, bool case_insensitive] )

Defines a named constant. See the section on constants for more details.

The name of the constant is given by name; the value is given by value.

The optional third parameter case_insensitive is also available. If the value TRUE is given, then the constant will be defined case-insensitive. The default behaviour is case-sensitive; i.e. CONSTANT and Constant represent different values.

例 1147. 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."

?>

如果成功则返回 TRUE,失败则返回 FALSE

See also defined(), constant() and the section on Constants.