How to list the functions in a PHP file

When debugging your PHP code you often run into an issue where you’re trying to find the scope of what variables are available. Whether you’re taking over a project from someone, or you’re using a CMS or framework, being able to list in an array all the functions comes handy.

Here’s the simple PHP function to get all the functions available to you:

function myfunc() {
echo 'Hello World!';
}
$list = get_defined_functions();
print_r($list);

This will output something like:

Array
(
[internal] => Array
(
[1] => func_num_args
[2] => func_get_arg
[3] => func_get_args
[4] => strlen
[5] => strcmp
[6] => strncmp
...
[750] => bcscale
[751] => bccomp
)
[user] => Array
(
[0] => myfunc
)
)

That gives you the internal, php core functions, and user defined functions (the ones you or your CMS defines). Let’s take this a step further and make a function that gets only the user defined functions.

function get_functions() {
$list = get_defined_functions();
$user_list = array_flip($list['user']);
return $user_list;
}
$list = get_functions();
print_r($list);

You can rename get_functions() to whatever you want it to be. I usually prefix my functions based on the specific CMS or framework I’m using.

Conclusion

You’ve just learned something pretty basic, but handy. Use with care.