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From: mouse@mcgill-vision.UUCP (der Mouse)
Newsgroups: net.lang.c
Subject: unterminated .h files, __CAT__, etc.
Message-ID: <470@mcgill-vision.UUCP>
Date: Mon, 28-Jul-86 18:54:11 EDT
Article-I.D.: mcgill-v.470
Posted: Mon Jul 28 18:54:11 1986
Date-Received: Wed, 30-Jul-86 01:43:20 EDT
References: <5722@think.COM> <2244@brl-smoke.ARPA>
Organization: McGill University, Montreal
Lines: 64

> Recently, through no fault of my own (honest, guv'nor!) I wound up
> including a header file with no terminating newline.

Fun, ain't it?

> My questions are directed more toward the handling of the missing
> newline itself:
> What do other preprocessors do in this kind of situation?

Well, in my preprocessor (yes, I rewrote cpp), a # is not special
except at the beginning of a line.  Hence we have the following:

x.c contains
	#include "y.c"
	#include "z.c"
	#include "y.c"
	this is x.c contents
y.c contains, without a terminating newline
	this is y.c contents
z.c contains
	this is z.c contents
then cc -E (with my preprocessor) produces
	# 1 "y.c"
	this is y.c 
	# 2 "x.c"
	contents#include "z.c"
	# 1 "y.c"
	this is y.c 
	# 4 "x.c"
	contentsthis is x.c contents
Notice that the last token has migrated from the included file into the
including file, and that the first #include has been output literally.

> What *should* X3J11 say about these cases, if anything?

I see nothing wrong with leaving it implementation-dependent (it is an
error if the file does not end with a newline).

On another topic,

> __STR__ and __CAT__ were suggested by Tom Plum in a late-night
> working session to resolve the remaining preprocessor issues,

> The Reiser CPP is definitely out.

I don't see what's wrong with Reiser cpp's answer to the str and cat
problems (formal substitution in strings and /**/).  Could someone
enlighten me?  The former (formals inside ""s) can bite, but only if
you're not aware of it (using the same name for a formal and a global
within the macro can bite too, so the possibility of being bitten will
not go away with __STR__).  The only thing I can see wrong with /**/
for __CAT__ is that cc -E -C, such as is used by lint, won't do
contatenation, but the preprocessor could easily be made to strip /**/
even under -C).
-- 
					der Mouse

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