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Path: utzoo!mnetor!seismo!rutgers!ames!amdahl!drivax!socha
From: socha@drivax.UUCP (Henri J. Socha (x6251))
Newsgroups: comp.lang.c
Subject: Re: Function prototypes (enforced)
Message-ID: <1460@drivax.UUCP>
Date: Fri, 1-May-87 18:26:47 EDT
Article-I.D.: drivax.1460
Posted: Fri May  1 18:26:47 1987
Date-Received: Sun, 3-May-87 03:52:52 EDT
References: <18346@ucbvax.BERKELEY.EDU> <7973@utzoo.UUCP> <796@rtech.UUCP>
Reply-To: socha@drivax.UUCP (Henri J. Socha (x6251))
Organization: Digital Research, Monterey
Lines: 55
Summary: compiler should force prototype definitions on all functions

In article <796@rtech.UUCP> jas@rtech.UUCP (Jim Shankland) writes:
>Henry Spencer (utzoo!henry) notes in passing:

>> [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 only one I can think of is that an implicit coercion will not be
>done when there is no function prototype in scope.  I would resolve
>that by requiring compilers to emit a fairly strongly worded warning
>whenever a program called a function without a prototype in scope.  

>Are there additional arguments against function prototypes?  If so,
>what are they?

 Well, just to back up (give an example) of what you said:

The Macintosh Lightspeed C (development environment!) from Think Technologies
has an option called  "Function Prototypes Required".  It can be
set as a default that is always enforced (unless explicitly disabled).

They also have a non-standardism (which I feel is a bug) in that
when a function is defined, the prototype form CAN NOT be used.

Therefore if this option is enabled, you must say:

	int main(int argc, char *argv[]);

	int main(argc, argv)	/* can't use prototype form here! (bug) */
	int argc;
	char * argv[];
	{
	.....
	}

Or you will get a compile error that the prototype for main was not given.

YES, (before you flame me) a prototype declaration at function definition
should be allowed but (and finally this is the point):

I WOULD RATHER BE FORCED TO DO UNNECESSARY DECLARATIONS THAN 
NOT KNOW IF ALL FUNCTIONS AND CALLS HAVE BEEN CORRECTLY CODED.

I have been burned more than once by the missing declaration of an external
LONG returning function or a mis-typed call argument.

How about it compiler writers?  Will you also install a switch
that DEMANDS prototype definitions for all functions so that
at least a minimum of type checking can be performed?

Disclaimer:  This is not (necessarily) the view of my employer.
--
-- 
UUCP:...!amdahl!drivax!socha                                      WAT Iron'75
"Everything should be made as simple as possible but not simpler."  A. Einstein