Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!uxc!uxc.cso.uiuc.edu!uxg.cso.uiuc.edu!uxe.cso.uiuc.edu!mcdonald
From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.lang.fortran
Subject: Re: Fortran graphics
Message-ID: <50500104@uxe.cso.uiuc.edu>
Date: 11 Feb 89 16:00:00 GMT
References: <4328@hubcap.UUCP>
Lines: 34
Nf-ID: #R:hubcap.UUCP:4328:uxe.cso.uiuc.edu:50500104:000:1658
Nf-From: uxe.cso.uiuc.edu!mcdonald    Feb 11 10:00:00 1989



>If and only
>if a comiler claims to produse object code compatible with that of
>another compiler should you attempt to link the two. Even then, as I
>said before, you usually must use a restricted subset of both languages.

Not entirely true. I have used assembly glue routines to link
Microsoft C and RyanMcFarland Fortran - and they use violently
different calling conventions. The restricted part is true:
you have to be sure that EITHER the run-time io systems are compatible,
OR make sure that one doesn't get loaded. 

With the Microsoft languages, there are relatively easy ways to
do this: compile with /Fa /Oil /Gs  to get rid of as many calls as
possible (remove stack check calls and use inline subroutines where
possible) and generate assembly output. Then edit the .asm files to
remove things like the __acrtused global. A MSC program done that way,
with NO floating arithmetic, and using no IO, only harmless 
calls like strcpy, etc, will be pretty generically useable. Floating
point is easy too, if you have an '87: use /FPi87 AND, and this
is bizarre in the extreme, make a dummy assembler routine containing
all those weird FISRQQ-like globals that appear in a link map you
get if you link without any run-time modules. That is, make variables
with those names and make them public, then assemble it and link with
your files. (Microsoft languages with /FPi87 generate actual '87
calls in their .obj modules. BUT, unless you do this bizarre thing,
Microsoft's LINKER REMOVES THOSE INSTRUCTIONS AND REPLACES THEM 
WITH SOFTWARE INTERRUPTS.)

If they would document things better, it would be easier to do 
links like this.

Doug McDonald