PHP: Get All User Constants

Last updated May 9th, 2024 at 03:02 pm

Sometimes I want to see all the constants I have defined. Here is some diagnostic PHP I use for displaying all user-defined constants.

function diag_defined_user_constants( $sort = true, $echo = true ) {
	$constants = get_defined_constants(true);
	$u_constants = $constants['user'];
	if ( $sort ) {
		ksort($u_constants);
	}
	if ( $echo ) {
		echo 'User Constants:<pre>' . print_r($u_constants, true) . '</pre>';
	} else {
		return $u_constants;
	}
}

The native PHP function get_defined_constants returns an associative array of all defined constants, including user-defined constants and those defined in PHP core and by its extensions. By including the optional categorize parameter and setting it to true, the function returns a multidimensional array whose first-dimension keys are the categories.

Since I care only about user-defined constants, line 3 defines the variable $u_constants accordingly. Note the use of the ksort function here, since the keys of the $constants['user'] array are associative.

I would call the function like this:

diag_defined_user_constants(); // using default arguments

I get a result that looks like this (with values hidden):

User Constants:

Array
(
	[ADD_HISTORY_PAGE] => [value_goes_here]
	[ADMIN_INCLUDES_PATH] => [value_goes_here]
	[CRM_ADD_HISTORY_PAGE] => [value_goes_here]
	[CRM_EDIT_CONTACT_PAGE] => [value_goes_here]
	[CRM_EDIT_HISTORY_PAGE] => [value_goes_here]
	[CRM_EDIT_RESULT_CODES_PAGE] => [value_goes_here]
	[HISTORY_REPORT_PAGE] => [value_goes_here]
	[MODULE_INCLUDES_PATH] => [value_goes_here]
	[MODULE_ROOT_DIR] => [value_goes_here]
	[ROOT_DIR] => [value_goes_here]
	[SHOW_DIAGS] => [value_goes_here]
	[SITE_FOOTER] => [value_goes_here]
	[SITE_HEADER] => [value_goes_here]
	[VIEW_HISTORY_PAGE] => [value_goes_here]
)

If you have questions or comments about this snippet of diagnostic PHP — or if you have some of your own diagnostic PHP to share — feel free to leave a comment.