Knowledge Base

How to determine if a PHP function is available

This article describes how to use the function_exists() function to determine whether or not a function is available for your PHP installation.

Determine if a PHP function is available

You can determine whether or not a PHP function is enabled for your web site by using the function_exists() function.

To determine if a function is available:

  1. Create a file that contains the following code. This sample code checks to see if the fsockopen() function is available. To check for another function, change the $function_name variable's value:
    <?php
        $function_name = "fsockopen";
        if ( function_exists($function_name ) ) {
            echo "$function_name  is enabled";
        }
        else {
            echo "$function_name  is not enabled";
        }
    ?>
    
  2. Save the file as function.php or something similar.

  3. Upload the file to your public_html directory.

  4. Use your browser to go to http://example.com/function.php, where example.com represents your web site's domain name. The page displays whether or not the function is enabled for your web site.

More Information

For more information about the function_exists() function, please visit http://us3.php.net/manual/en/function.function-exists.php.