| I. | Na początek | |
| II. | Instalacja i konfiguracja | |
| III. | Opis języka | |
| IV. | Bezpieczeństwo | |
| V. | Możliwości | |
| VI. | Opis funkcji | |
| VII. | Zend API | |
| VIII. | PHP API: Interfejs rozszerzeń | |
| X. | Dodatki | |
Copyright © 1997-2006 the PHP Documentation Group
Returns TRUE if the named constant given by name has been defined, FALSE otherwise.
Notatka: If you want to see if a variable exists, use isset() as defined() only applies to constants. If you want to see if a function exists, use function_exists().
See also define(), constant(), get_defined_constants(), function_exists(), and the section on Constants.