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# define

(PHP 3, PHP 4, PHP 5)

define -- Defines a named constant

## Description

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

Defines a named constant at runtime. 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.

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." ?>`

Returns `TRUE` on success or `FALSE` on failure.

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

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