function_exists()

function_exists - Return

TRUE
if the given function has been defined

Syntax

bool function_exists (string $function_name)

Arguments

• function_name - The function name, as a string.

Description

Checks the list of defined functions, both built-in (internal) and user-defined, for function_name.

Version

PHP 4, 5

Return value

Returns TRUE if function_name exists and is a function, FALSE otherwise.