   #PHP Manual Function Handling functions func_num_args
   get_defined_functions

   PHP Manual
   Prev  Next
   ______________________________________________________________________

                                function_exists

   (PHP 3>= 3.0.7, PHP 4 )
   function_exists --  Return 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. Returns TRUE on success or FALSE on
   failure.

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

   Note that 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). Also note that function_exists() will
   return FALSE for constructs, such as include_once() and echo().

   See also method_exists() and get_defined_functions().
   ______________________________________________________________________

   Prev          Home                  Next
   func_num_args  Up  get_defined_functions

