dxf R12

Searching for the way fonts are working in dxf files I found something about the dxf format.
Once claus82 told about some problems regarding other cad software reading files from LCad:
http://forum.librecad.org/dimensions-reading-between-librecad-and-other-softwares-tp5708262.html
At this time I noticed the leading blanks in some lines:http://forum.librecad.org/dimensions-reading-between-librecad-and-other-softwares-tp5708262p5708347.html

And now I found this:
http://www.mediatel.lu/workshop/graphic/3D_fileformat/h_dxf12.html
And it says:
"A DXF file is composed of many groups, each of which occupies two lines in the DXF file. The first line of a group is a group code, which is a positive nonzero integer output in FORTRAN I3 - that is, right-justified and blank filled in a three-character field (the exception to this is the four-digit extended entity data group codes, which are output in FORTRAN I4)."

BUT in the pdf file for AutoCAD® 2002
http://usa.autodesk.com/adsk/servlet/item?id=12272454&linkID=10809853&siteID=123112
I can't find something about FORTRAN.
So does that mean the "FORTRAN I3" format is R12 only?

Hi,

I3 is a format for numbers in the programming language FORTRAN. I think it was used in the DXF documentation to specify the code format that it is better understood by the developers. In the early 90's, when R12 was released, FORTRAN was very popular I think.

The I3 format only says that the code must have 3 digits, with leading blanks if the code is smaller than 100. This format was used in DXF documentation up to and including 2004/2005/2006 (ACADVER AC1018).
Starting with DXF 2007 (AC1021) documentation, the examples uses group codes which are aligned left, without the leading blanks.

Modern DXF libraries should handle both versions, with or without leading blanks, independent of the used DXF file version.

Armin