PHP Magic Constants

There are various predefine PHP Magic Constants. It starts with underscore(__) and ends with double underscore.

Magic Constant	Description
__LINE__	To check current line number of the file.
__FILE__	To check full path and filename of the file.
__FUNCTION__	To check function name.
__CLASS__	To check class name.
__METHOD__	To check class method name.
PHP_VERSION	To check PHP version.
PHP_INT_MAX	To check PHP integer value limit. etc

Let us take an example of Magic Constants Example1.

<!DOCTYPE html>
<html>
<body>
<?php
echo "Used of [ __LINE__ ] Magic Constant"."<br>";
  echo "The Line number : ". __LINE__;
?>
</body>
</html>

Example 2.

<?php
class test{
  function test(){
              echo "Function of test class : ". __FUNCTION__ ."<br/>";
  }
  functiontestme(){
              echo "Method of test class : ". __METHOD__ ."<br/>";
              echo "Class : ". __CLASS__;                                
  }
}
$object=new test();
$object->test();
$object->testme();
?>

Output Function of test class : test Function of test class : test Method of test class : test::testme Class : test