Xref: utzoo comp.misc:11949 alt.folklore.computers:10652
Newsgroups: comp.misc,alt.folklore.computers
Path: utzoo!censor!comspec!scocan!tom
From: tom@sco.COM (Tom Kelly)
Subject: Re: "Invalid null command"
Organization: SCO Canada, Inc. (formerly HCR Corporation)
Date: Wed, 03 Apr 1991 01:09:09 GMT
Message-ID: <1991Apr03.010909.28628@sco.COM>
References: <1991Apr2.005620.11434@ico.isc.com>
Sender: news@sco.COM (News administration)

In article <1991Apr2.005620.11434@ico.isc.com> rcd@ico.isc.com (Dick Dunn)
pedantically derives the C version of good old IEFBR14.  In that spirit,
here are some pedantic comments:

First try:

>	main()
>	{
>	}
 ...

>Here's the first correction:
>	main()
>	{
>		exit(0);
>	}
>But to make this proper in today's brave new world, we need <stdlib.h>.

Actually, no you don't.  The ANSI C Standard, Section 2.1.2.2
"Hosted Environment", subparagraph titled "Program termination" says:

	A return from the initial call to the main function is equivalent
	to calling the exit function with the value returned by the
	main function as its argument ... [Jan 11 '88 draft]

So, we can replace "exit(0)" with "return(0)".

>Also, for formality's sake and international propriety, we should add the
>normally-obligatory setlocale() call (actually not necessary--this may be
>the *only* program for which that's true--but it's hard to pass up poking
>fun at a requirement to set a default explicitly), and this in turn
>requires <locale.h>.  OK, so here's the penultimate version of IEFBR14.c,
>our properly ANSI and internationalized (unless I screwed up) program-to-
>do-nothing:
>
>	#include <stdlib.h>
>	#include <locale.h>
>
>	#ifndef	lint
>	static char *sccsid = "%W% - %E%";
>	#endif
>
>	/*ARGSUSED*/
>	main(argc,argv)
>	int	argc;
>	char	**argv;
>	{
>		setlocale(LC_ALL, "");
>		exit(0);
>	}

Not really.  Section 4.4.1.1 says:

	At program startup, the equivalent of "setlocale(LC_ALL, "C")"
	is executed.

This is the responsibility of the implementation, (e.g., done by crt0)
so there is a well-defined default locale.  Since this program produces no
locale-dependent output, there is no need to change the locale from the
default.

Furthermore, the declaration of main could be "int main(void)":

	#ifndef	lint
	static char *sccsid = "%W% - %E%";
	#endif

	int
	main(void)
	{
		return(0);
	}


That doesn't look quite so bad.  Unfortunately, it is not strictly
conforming, because the termination status is implementation defined.
This is because the committee could not agree that a return (or exit)
value of zero means "success"; there are systems on which this is not
true.  [I won't say more, they know where I live].  So, we have
to change "return(0)" to "return(EXIT_SUCCESS)", which, tragically,
requires "#include <stdlib.h>".  But this is not required if you
only want to run on Unix (and _probably_ POSIX-conforming systems).

>To create the final version, all you need is your local draconian
>corporate screenful of copyright notice and disclaimer.

You forgot the 40 pounds of paperwork to get it included in the
release ...

Tom Kelly  (416) 922-1937
SCO Canada, Inc. (formerly HCR) 130 Bloor St. W., Toronto, Ontario, Canada
{utzoo, utcsri, uunet}!scocan!tom or tom@sco.com