(3.0.7 - 3.0.18 only, PHP 4 >= 4.0.0)
function_exists -- Return TRUE if the given function has been definedChecks the list of defined functions for function_name. Returns TRUE if the given function name was found, FALSE otherwise.
if (function_exists('imap_open')) { echo "IMAP functions are available.<br>\n"; } else { echo "IMAP functions are not available.<br>\n"; } |
See also method_exists().