define

Function • Params changed in PHP 8.1

Defines a named constant.

PHP 5
PHP 7
PHP 8.0
Improved
PHP 8.1
Improved
PHP 8.2
PHP 8.3
PHP 8.4
PHP 8.5

define Function synopsis

define(
    string $constant_name,
    mixed $value,
    bool $case_insensitive = false
  ): bool

Parameters

$constant_name

Typestring

The name of the constant.

$value

Typemixed

The value of the constant. In PHP 5, $value must be a scalar value (int, float, string, bool, or null). In PHP 7, array values are also accepted.

$case_insensitive

OptionalTypeboolDefault valuefalse

If set to true, the constant will be defined case-insensitive. The default behavior is case-sensitive; i.e. CONSTANT and Constant represent different values.

Return value

Typebool

Returns true on success, false on failure

Changes to the define Function

PHP 8.1

  • Parameter type added for parameter #2 ($value): mixed
  define(
      string $constant_name,
-     $value,
+     mixed $value,
      bool $case_insensitive = false
    ): bool

PHP 8.0

  • Return type added: bool
  • Parameter type added for parameter #1 ($constant_name): string
  • Parameter type added for parameter #3 ($case_insensitive): bool
  • Parameter default value added for position #3 ($case_insensitive): false
  define(
-     $constant_name,
+     string $constant_name,
      $value,
-     $case_insensitive
+     bool $case_insensitive = false
-   )
+   ): bool

define Function Availability

PHP VersionAvailability
PHP 8.5Future Release Yes
PHP 8.4Upcoming Release Yes
PHP 8.3Supported (Latest) Yes
PHP 8.2Supported Yes
PHP 8.1Security-Fixes Only Yes
PHP 8.0Unsupported Yes
PHP 7.4Unsupported Yes
PHP 7.3Unsupported Yes
PHP 7.2Unsupported Yes
PHP 7.1Unsupported Yes
PHP 7.0Unsupported Yes
PHP 5.6Unsupported Yes
PHP 5.5Unsupported Yes
PHP 5.4Unsupported Yes
PHP 5.3Unsupported Yes