Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!ucsd!ucbvax!KARRON.MED.NYU.EDU!karron
From: karron@KARRON.MED.NYU.EDU
Newsgroups: comp.sys.sgi
Subject: Re: Mixing ANSI and K & R 1 code.
Message-ID: <9011171557.AA16135@karron.med.nyu.edu>
Date: 17 Nov 90 15:57:39 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: karron%CMCL2.NYU.EDU@cunyvm.cuny.edu
Organization: The Internet
Lines: 52

>>Seems you can't have newstyle argument lists (ANSI) receiving parameters
>>from old styles,non prototyped code.
>>
>>I first tried to write all my new stuff in ANSI code, but it would
>>always get float (Coord) arguments wrong.
>
>...
>
>>This is something that should be fixed.
>
>Fine, hop in your time machine, go back to the ANSI C meetings where
>they decided that if you have a routine declared with prototypes with
>arguments that are "float", that it really gets passed "float"s, not
>"double"s, and convince them otherwise.  That should fix it....
>
>If that's not possible, you're out of luck unless you can convince SGI
>or whoever to have "float" just mean "double", which is unlikely given
>the number of other things it'll probably break....
>
>If you have a routine that is to have prototypes, is to be passed
>floating-point arguments, and is to be called by old-style C, make its
>arguments "double" - even if that means not giving them type "Coord".
>

Sgi has make a weak attempt to address this "standard" problem. There is a
 cc -float flag to stop default promotion to doubles in argument/parameter
lists. Just seems not to work they way I hoped in spliced code...

I am not finished testing this out, so if anyone has any more insight, I
would like for you to speak up.

My design goal is to mix a library of K & R 1 code with ANSI C, and when the
K & R stuff is upgraded, not change my ANSI C code. I guess that there
is no performance penalty for passing by value floats as doubles, but I am
not certain of it. It is more bytes to push to the stack. Another suggested
solution is to make ANSI headers for K & R 1 code. This is a slippery issue
and I am not certain  about a robust answer. At least the run time code really
breaks when the problem arises ! (Only with floats).

Cheers!

dan.

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