php predefined constants
<?php
// EXAMPLE (a superglobal is a variable that is predefined within the environment)
echo "This is line " . __LINE__ . " of the [" . __FILE__ . "] file";
// OUTPUT: This is line 31 of the [C:/MadeUpFolder/MadeUpFile.php] file
// Superglobals
/******************+***************************************************
| <<< VARIABLE >>> |<<< DESCRIPTION >>>
+******************+***************************************************
| __FILE__ | The current line number of the file.
+------------------+---------------------------------------------------
| __LINE__ | The full path and filename of the file
+------------------+---------------------------------------------------
| __DIR__ | The directory of the file
+------------------+---------------------------------------------------
| __FUNCTION__ | The function name
+------------------+---------------------------------------------------
| __CLASS__ | The class name
+------------------+---------------------------------------------------
| __METHOD__ | The class method name
+------------------+---------------------------------------------------
| __NAMESPACE__ | The name of the current namespace (case-sensitive)
+------------------+---------------------------------------------------
*/
?>