Constants PHP Manual Prev Next Chapter 8.
Constants PHP defines several constants and provides a mechanism for defining more at run-time.
The name of the script file presently being parsed. If used within a file which has been included or required, then the name of the included file is given, and not the name of the parent file. The number of the line within the current script file which is being parsed. If used within a file which has been included or required, then the position within the included file is given. TRUE A true value.