Je was op zoek naar: undefined (Koreaans - Frans)

constants may not be redefined or undefined once they have been set; and
le troisième paramètre optionnel case_insensitive est une valeur booléenne.

calculate (base raised into power exp) modulo mod. if exp is negative, result is undefined.
si exp est négatif, le résultat est indéfini.

all registered variables are serialized after the request finishes. registered variables which are undefined are marked as being not defined. on subsequent accesses, these are not defined by the session module unless the user defines them later.
les options de configuration track_vars et register_globals influencent la manière de stockage et déstockage des variables.

call_user_function() returns success on success, and failure in case the function cannot be found. you should check that return value! if it returns success, you are responsible for destroying the retval pval yourself (or return it as the return value of your function). if it returns failure, the value of retval is undefined, and you mustn't touch it.
si la réponse est failure, la valeur de retval est indéfinie, et vous ne devez pas y toucher.