Re: [Bug fortran/35916] problem running gfortran 4.4.0 in Vista

[Tobias Burnus <burnus at net-b dot de>]

Jerry DeLisle wrote:
> > However, some large Fortran libraries which were built a decade or so 
> > ago for g77, are still very much in use, with very little chance of 
> > them ever being updated. I have tried to build one of these from 
> > source, with the provided make files, using gfortran, but gave up 
> > very quickly after being inundated with errors and warnings.
> >   
> Regarding g77 and gfortran compatibility.  We would really like to see 
> examples of code that is causing the issues.
gfortran should be able to compile about any g77 code; there are very 
few things of g77 which gfortran does not support. On the other hand, 
gfortran contains several vendor extensions which g77 did not. Thus, in 
total, gfortran should be able to compile more legacy programs than g77. 
(At least this is my experience.)

As Jerry already said: We are very interested to see Fortran code which 
g77 compiles but gfortran does not; and with very few exceptions, we 
intent to implement those missing bits in gfortran.

> > In my experience, one of the main differences is the definition of 
> > structures, and the structure syntax (e.g. the use of "%" instead of 
> > "."). Is there a way (compiler option or something) to compile old 
> > code with old structure definitions, using gfortran, and without 
> > replacing them in the source code?

This sounds like DEC's STRUCTUREs. This is something which gfortran will 
almost certainly never support. (The reason is that it is very difficult 
to support such that it works with user-defined operators which also use 
dots. Additionally, Fortran 90 introduced TYPE which does the same - and 
even more. Intel's ifort supports STRUCTURE and Intel struggled for 
quite a while to get it properly working with user-defined operators.)

However, to my knowledge g77 did not support STRUCTURE, UNION, RECORD, 
MAP neither. (Which both a quick test and the g77 manual confirmed.)

For gfortran, the answer is to replace STRUCTURE by Fortran 90's TYPE as 
written at
  http://gcc.gnu.org/onlinedocs/gfortran/STRUCTURE-and-RECORD.html

Since you wrote that it works with g77, I'm curious about what exactly 
you have; as STRUCTURE is not supported by g77 it must be something 
else, but what?

If you have STUCTURE, it is relatively easy to replace it by Fortran 90 
syntax using, e.g., "sed" or "perl" or anything else which supports 
regular expressions.

Tobias

PS: No idea about your Windows Vista problem -- I also use Linux; 
hopefully someone else will find out how to get gfortran running on your 
machine.