Php constant define () constant (), defined ()

Php constant define () constant (), defined () define -- defines a constant. if true is defined, booldefine (stringname, mixedvalue [, boolcase_insensitive]) is not case sensitive during read. constants can only contain scalar data (B php constants define () constant (), defined ()

Define -- defines a constant. if it is set to true, the read process is case insensitive.

Bool define (string name, mixed value [, bool case_insensitive])

Constants can only contain scalar data (Boolean,Integer,FloatAndString).

Define ("CONSTANT", "Hello world .");
Echo CONSTANT; // outputs "Hello world ."
Echo Constant; // outputs "Constant" and issues a notice.

Define ("GREETING", "Hello you.", true );
Echo GREETING; // outputs "Hello you ."
Echo Greeting; // outputs "Hello you ."

?

?

==========================================================

Constant () -- read a constant

MixedConstant(String name)

?

Define ("MAXSIZE", 100 );

Echo MAXSIZE;
Echo constant ("MAXSIZE"); // same thing as the previous line

?

====================================

?

Defined -- determine whether a constant is defined

?

BoolDefined(String name)

?

If (defined ('constant ')){
???? Echo CONSTANT;
}

?

========================================================== ====================

?

Predefined Constants

?

_ FILE __?? Obtain the physical address of a file? Note: There are two underscores (_) between the left and right.

?

Echo _ FILE __??? // C: \ wamp \ www \ T1 \ 1.php

?

?

?

?