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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: comp.lang.c
Subject: Re: Function prototypes (was: miscellaneous unrelated stuff)
Message-ID: <8016@utzoo.UUCP>
Date: Mon, 11-May-87 15:24:41 EDT
Article-I.D.: utzoo.8016
Posted: Mon May 11 15:24:41 1987
Date-Received: Mon, 11-May-87 15:24:41 EDT
References: <18346@ucbvax.BERKELEY.EDU> <7973@utzoo.UUCP>, <796@rtech.UUCP>
Organization: U of Toronto Zoology
Lines: 29

> > [Function prototypes] have other problems, and I'm not sure they were a
> > good idea....
> 
> This got me curious:  what are the problems with function prototypes?

The three that immediately come to mind are:

1. Considerable disaster potential when moving code between environments
which differ in how they do prototyping.  Remember that many (most?)
prototypes will be picked up with header files, not explicitly typed by
the programmer.  What happens when that code gets moved to a system with
a non-prototyping compiler?  (Such compilers won't go away overnight.)
Less drastic and still more subtle, what happens when the code gets moved
to a system which doesn't declare quite the same set of functions in the
prototypes in its headers?  (Don't tell me this shouldn't happen, it will.)

2. Some of the coercions provided by function prototypes are distinctly
unsafe, e.g. the shortening ones.  Again, prototypes from header files
are a nice way to have this happen without the programmer noticing it --
and it's not clear that even lint will complain.

3. They are a significant change to C, implementation experience with them
is distinctly limited, and they aren't vitally needed.  There is room for
debate about whether X3J11 violated the "standardize the existing language,
not a new one" rule, and function prototypes are the most conspicuous
evidence for violation.
-- 
"The average nutritional value    Henry Spencer @ U of Toronto Zoology
of promises is roughly zero."     {allegra,ihnp4,decvax,pyramid}!utzoo!henry