PHP Custom Global constants and class constants

Source: Internet
Author: User
/** * 1, define (name,value,case_insensitive) custom global constants, default case Sensitive * 2, Const defines class constants. * 3, the constant name do not use "$" * 4, the name of the constant all use uppercase letters. *///defines global constants Languagedefine (' LANGUAGE ', ' China '); Echo language;//languageecho language;//China//define Global constants Cndefine (' CN ', ' China ', TRUE) echo cn;//China echo cn;//China//define class constant classes Consttest{const VERSION = ' 1.0 '; function consttest () {//class internally using "Self:: constant name" Call, Cannot use $thisecho ' self::version= '. self::version;}} Instantiate Consttest, the purpose is to call the constructor new Consttest ();//External call class constant, through the "class name:: Constant name" directly called, do not need to instantiate. Echo ' version= '. (consttest::version); Echo ' <br> ';//array get_defined_constants ([bool $categorize = false]) returns all defined constants//print_r (Get_defined_constants (true));//bool defined (string $name) checks that the constant for the name is defined. Echo defined (' CN ')? ' True ': ' false ';

Printing results:

Language
China
China
China
self::version=1.0
version=1.0
True

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