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(PHP 3, PHP 4 )

define -- Defines a named constant.


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

Defines a named constant, which is similar to a variable except:

  • Constants do not have a dollar sign '$' before them;

  • Constants may be accessed anywhere without regard to variable scoping rules;

  • Constants may not be redefined or undefined once they have been set; and

  • Constants may only evaluate to scalar values.

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 1 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." ?>       

Define() returns TRUE on success and FALSE if an error occurs.

See also defined() and the section on Constants.