define
Description
Defines a named constant
Syntax
define(string $constant_name, mixed $value): bool
Parameters
constant_nameThe name of the constant.
Note: It is possible to define() constants with reserved or even invalid names, whose value can (only) be retrieved with constant(). However, doing so is not recommended.
valueThe value of the constant.
Warning: While it is possible to define resource constants, it is not recommended and may cause unpredictable behavior.
Return
Returns TRUE on success or FALSE on failure.
Examples
1 · constant_name value · null
<?
define("MYCONSTANT", null);
var_export(MYCONSTANT);
?>NULL
2 · constant_name value · boolean
<?
define("MYCONSTANT", true);
var_export(MYCONSTANT);
?>true
3 · constant_name value · float
<?
define("MYCONSTANT", 0.1);
echo MYCONSTANT;
?>0.1
4 · constant_name value · integer
<?
define("MYCONSTANT", 1);
echo MYCONSTANT;
?>1
5 · constant_name value · string
<?
define("MYCONSTANT", "Hello World!");
echo MYCONSTANT;
?>Hello World!
6 · constant_name value · array
<?
define("MYCONSTANT", array(0, 1));
print_r(MYCONSTANT);
?>Array
(
[0] => 0
[1] => 1
)
7 · Return
<?
$return = define("MYCONSTANT", array(0, 1));
var_export($return);
?>true
