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From: patrick@convex.COM (Patrick F. McGehearty)
Newsgroups: comp.lang.fortran,comp.unix.cray
Subject: Re: why has Cray dropped CPP support from cf77?
Message-ID: <1991Feb18.145116.3840@convex.com>
Date: 18 Feb 91 14:51:16 GMT
References: <1298@red8.qtp.ufl.edu>
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In article <1298@red8.qtp.ufl.edu> bernhold@qtp.ufl.edu (David E. Bernholdt) writes:
>
>The latest release of cf77 no longer supports automaticly running .F
>files through CPP before compiling them.  This move seems to be a step
>backward from the what I think is a _very_ useful feature common to
>_many_ unix-based fortran implementations.  Does anyone know why they
>did it?

I know nothing about Cray's support decisions, but I do know that
while using cpp works as a preprocessor for many programs, it also
has weaknesses since the tokenizing rules for fortran and C are so
different.  For example, any token (string, identifier, whatever) that is
spread over a continuation line is not recognized by CPP.  Similarly, any
token with embedded spaces is not recognized by CPP.  Comment lines
in the middle of continuation lines can cause strange behavior.
A blanket decision to run CPP over large "dusty-deck" unstructured Fortran
programs can reach up and bite you without giving any indication of what
happened.  Use with caution!