get_defined_constants()
get_defined_constants() — Returns an associative array with the names of all the constants and their values.
Built-in function of PHP 8.5. The manual lists it as available in PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.
What it does
Returns the names and values of all currently defined constants. This includes constants defined by extensions and those created using the define() function. However, it excludes magic constants, which resolve at compile time.
Signature
get_defined_constants(bool $categorize = false): array
Parameters
| Parameter | Type | What it takes |
|---|---|---|
| $categorize | bool | Causing this function to return a multi-dimensional array with categories in the keys of the first dimension and constants and their values in the second dimension. <?php define("MY_CONSTANT", 1); print_r(get_defined_constants(true)); ?> The above example will output something similar to: Array ( [Core] => Array ( [E_ERROR] => 1 [E_WARNING] => 2 [E_PARSE] => 4 [E_NOTICE] => 8 [E_CORE_ERROR] => 16 [E_CORE_WARNING] => ... |
Return value
Returns an array of constant name => constant value array, optionally grouped by extension name registering the constant.
Example
A runnable snippet:
print_r(get_defined_constants());
Output:
Array ( [E_ERROR] => 1 [E_WARNING] => 2 [E_PARSE] => 4 [E_NOTICE] => 8 [E_CORE_ERROR] => 16 [E_CORE_WARNING] => 32 [E_COMPILE_ERROR] => 64 [E_COMPILE_WARNING] => 128 [E_USER_ERROR] => 256 [E_USER_WARNING] => 512 [E_USER_NOTICE] => 1024 [E_ALL] => 30719 [TRUE] => 1 )
See also
defined(), constant(), get_loaded_extensions(), get_defined_functions(), get_defined_vars()
All PHP 8.5 built-in functions
Reference card built from the PHP manual page get_defined_constants() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.