Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!uwm.edu!rpi!uupsi!sunic!tut!tukki.jyu.fi!sakkinen
From: sakkinen@tukki.jyu.fi (Markku Sakkinen)
Newsgroups: comp.lang.fortran
Subject: Re: Dates for the different versions of FORTRAN?
Message-ID: <1990Aug17.123818.8951@tukki.jyu.fi>
Date: 17 Aug 90 12:38:18 GMT
References: <3093.26c6b1cd@cc.curtin.edu.au> <9008151155.AA11309@thep.lu.se> <140686@sun.Eng.Sun.COM>
Reply-To: sakkinen@jytko.jyu.fi (Markku Sakkinen)
Organization: University of Jyvaskyla, Finland
Lines: 29

Note: This is the second posting of an article that apparently
did not go out at first.  Sorry if somebody receives it twice.

In article <140686@sun.Eng.Sun.COM> wsb@boise.Eng.Sun.COM (Walt Brainerd) writes:
>In article <9008151155.AA11309@thep.lu.se>, magnus@THEP.LU.SE (Magnus Olsson) writes:
>> 
>> The later versions of Fortran (IV, 66, 77) are reasonably downward
>> compatible with each other, even though there are some discrepancies,
>> such as the handling of a degenerate DO loop (DO 10 I=1,0 ...).
>
>The STANDARD Fortran 77 was compatible with the STANDARD Fortran 66
>because "zero-trip" DO loops were not legal in Fortran 66. [...]
> ...

There is at least one true incompatibility in DO loops.
STANDARD Fortran 66 allowed jumps into DO loops from the outside
under the rather complicated "extended range" rules.
STANDARD Fortran 77 prohibits such jumps completely.
However, as I mentioned in this newsgroup (almost a year ago?),
most compiler writers haven't taken notice yet - well, what
can you expect in mere 12 years?

Markku Sakkinen
Department of Computer Science
University of Jyvaskyla (a's with umlauts)
Seminaarinkatu 15
SF-40100 Jyvaskyla (umlauts again)
Finland
          SAKKINEN@FINJYU.bitnet (alternative network address)