Recognize system Constants

System constants are defined by PHP. They can be used directly. common systems are:

(1) _ file _: PhP program file name. It helps us to obtain the physical location of the current file on the server.

(2) _ line _: Number of PHP program files. It tells us the number of lines in the current Code.

(3) php_version: version number of the current parser. It tells us the version number of the current PHP parser. We can know in advance whether our PHP code can be parsed by the PHP parser.

(4) php_ OS: name of the operating system for executing the current PHP version. It tells us the name of the operating system used by the server, and we can optimize our code based on the operating system.

<? PHP

Echo _ file __;

Echo "<br/> ";

Echo _ line __;

Echo "<br/> ";

Echo php_version;

Echo "<br/> ";

Echo php_ OS;

Echo "<br/> ";

?>

 
./Index. php45.3.28linux
 

Recognize system Constants