Path: utzoo!attcan!uunet!mailrus!uflorida!mephisto!prism!sun13!gw.scri.fsu.edu!pepke
From: pepke@gw.scri.fsu.edu (Eric Pepke)
Newsgroups: comp.sys.sgi
Subject: 3.3 C Weirdness
Message-ID: <761@sun13.scri.fsu.edu>
Date: 24 Sep 90 15:25:51 GMT
Sender: news@sun13.scri.fsu.edu
Organization: Florida State University, but I don't speak for them
Lines: 74

There is a weirdness in the C that comes with 3.3 when the -prototypes 
argument is supplied.

I like to put prototypes in the .h file associated with each .c file, and 
then use old style definitions in the .c file.  That way, if I want to 
compile on a 3030, I just hack out the prototypes and it compiles fine.

With the new C, however, I sometimes get some odd error messages of the 
form

old/new style declaration and definition of <function name> argument  <#> 
mismatch: change the definition to the new (function prototype) style.

As far as I can tell, this does not in any way affect code generation; 
everything compiles fine.  It only seems to occur when the argument type 
in the prototype is a different size from the type it is promoted to when 
normally passed on the stack.  

For example, an int is the same size as a long, and a short is shorter.  
Integer arguments are normally passed as ints, so shorts and chars are 
ordinarily promoted to ints when passed.

This fragment would compile fine:

void bork(int);

void bork(i)
int i;
{
}

These would fail:

void face(char);

void face(c)
char c;
{
}

void fat(short);

void fat(s)
short s;
{
}

However, both of these would work:

void face(char c)
{
}

void fat(short s)
{
}

This behavior puzzles me, because by the time the parser gets to the open 
bracket, which is where the error is detected, it has enough semantic 
information to do the right thing no matter whether new- or old-style 
definitions are used.  Selectively to reject old-style definitions seems 
needlessly purist.

Does there exist a fix or workaround for this?  I would call the hotline, 
were it not for the difficulty in explaining things like this in detail 
over the phone.

Eric Pepke                                    INTERNET: pepke@gw.scri.fsu.edu
Supercomputer Computations Research Institute MFENET:   pepke@fsu
Florida State University                      SPAN:     scri::pepke
Tallahassee, FL 32306-4052                    BITNET:   pepke@fsu

Disclaimer: My employers seldom even LISTEN to my opinions.
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