Online PHP Function(s){ #Test PHP functions online!; }

  •  
 

function_exists

(PHP 4, PHP 5)

function_existsReturn TRUE if the given function has been defined

Description

bool function_exists ( string $function_name )

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

More info
Hide info

Parameters

function_name

The function name, as a string.

Return Values

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

Note:

This function will return FALSE for constructs, such as include_once() and echo().

Examples

Example #1 function_exists() example

<?php
if (function_exists('imap_open')) {
    echo 
"IMAP functions are available.<br />\n";
} else {
    echo 
"IMAP functions are not available.<br />\n";
}
?>

Notes

Note:

A function name may exist even if the function itself is unusable due to configuration or compiling options (with the image functions being an example).

See Also

 

 

 


Comments

 
 
      © 2019 OnlinePHPFunctions.com | Disclaimer |       PHP versions: 7.3.5, 7.2.18, 7.2.4, 7.1.29, 7.1.0, 7.0.14, 7.0.5, 7.0.4, 7.0.3, 7.0.2, 7.0.1, 5.6.29, 5.6.20, 5.6.19, 5.6.18, 5.6.17, 5.6.2, 5.5.34, 5.5.33, 5.5.32, 5.5.31, 5.5.18, 5.5.5, 5.5.0.a6, 5.5.0.a.5, 5.5.0.a.2, 5.4.34, 5.4.21, 5.4.13, 5.4.12, 5.4.11, 5.4.10, 5.4.9, 5.4.8, 5.4.7, 5.4.6, 5.4.5, 5.4.4, 5.4.3, 5.4.2, 5.4.1, 5.4.0, 5.3.29, 5.3.27, 5.3.23, 5.3.22, 5.3.21, 5.3.20, 5.3.19, 5.3.18, 5.3.17, 5.3.16, 5.3.15, 5.3.14, 5.3.13, 5.3.12, 5.3.11, 5.3.10, 5.3.2, 5.3.1, 5.3.0, 5.2.17, 5.2.16, 5.1.6, 5.1.5, 5.0.5, 5.0.4, 4.4.9