Path: utzoo!attcan!uunet!lll-winken!ames!ncar!gatech!gitpyr!loligo!mccalpin
From: mccalpin@loligo.cc.fsu.edu (John McCalpin)
Newsgroups: comp.lang.fortran
Subject: Re: An exercise in futility
Message-ID: <454@loligo.cc.fsu.edu>
Date: 17 Jan 89 13:53:34 GMT
References: <587@mbph.UUCP>
Reply-To: mccalpin@loligo.cc.fsu.edu (John McCalpin)
Organization: Supercomputer Computations Research Institute
Lines: 40
Keywords:

In article <587@mbph.UUCP> hybl@mbph.UUCP (Albert Hybl 
Dept of Biophysics  SM) writes: Consider the following program:
>*  Increase the value of K until the program fails.
>      PARAMETER (K=24)
>      CHARACTER AND(K)*1,DNA*(K)
>      EQUIVALENCE (DNA,AND)
>      DNA(K-23:K) = 'An exercise in futility!'
>      PRINT *,K,(AND(J+K-24),J=1,24)
>      END
>What does the ANSI X3.9-1978 standard say are the maximum allowable
>sizes for the character array AND(K)*1 and the character variable
>DNA*(K)?
>Albert Hybl, PhD.              Office UUCP: uunet!mimsy!mbph!hybl

Of course *you* are wainting in the wings with the *right* answer to this
problem.  What number do you suggest?  It sounds like you want a number
of several millions so that you can fit your genome sequences in.  That
is nice, except that it means that in *your* world, no standard IBM PC
could ever have a valid Fortran language system, because there ain't enough
core....

The problem is NOT that the standard allows machine/implementation-
dependent features, but rather that the standard does not seem to require
that the vendor ever tell us what these implementation-dependent
features are!  I, for one, would like any standard-conforming Fortran
system to include a document page listing the implementation-dependent
limitations, e.g.:
	maximum size of character string (e.g. char*K string)
	maximum integer value
	maximum and minimum floating-point values
	maximum array size (e.g. 64kB on old IBM PC compilers)
	argument range limits for ALL intrinsic math functions
	etc....
I am sure I am forgetting many more.... Such info, available in one place,
woudl make porting of standard-conforming Fortran code much easier.
-- 
----------------------   John D. McCalpin   ------------------------
Dept of Oceanography & Supercomputer Computations Research Institute
mccalpin@masig1.ocean.fsu.edu		mccalpin@nu.cs.fsu.edu
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