Definition
Specifies the left-most position of the file extension for those operating systems that present the file name extension separated from the main file name.
Required Values
For Fixed list line format, enter the column number, counting the first column at the extreme left as column 1. For Blank Delimited list line format, enter the field number, counting the first field at the far left as field 1. If there is no file extension (as on UNIX systems) set the value to zero (0).