Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!hoptoad!gnu
From: gnu@hoptoad.uucp (John Gilmore)
Newsgroups: comp.lang.c
Subject: ! operator in constant expressions
Message-ID: <3813@hoptoad.uucp>
Date: 10 Jan 88 10:46:03 GMT
Organization: Nebula Consultants in San Francisco
Lines: 27

I just wrote an interesting test program for ! and haven't yet found
a compiler that correctly implements the draft ANSI standard for it.
Try it on yours, and let me know (if it works -- I already believe it
will fail).  If anyone can show me how this program is not fully
conformant to the draft standard, I would also like to know.


int install = !0;	/* Gcc 1.16 said "initializer is not constant" */
			/* Gcc 1.17 gets wrong answer! */
char foo = !1;
int bar = !3.14156;	/* SunOS 3.3 cc said "Illegal initialization" */
int pno = ! &bar;	/* Gcc 1.17 said "initializer for static variable
			   uses complex arithmetic" */
int pyes = !(char *)0;

main() {
	if (install && !foo && !bar && pyes && !pno)
		printf("Test passed\n");
	else
		printf("FAILED, install=%d, foo=%d, bar=%d, pno=%d, pyes=%d\n",
			install, foo, bar, pno, pyes);
}
-- 
{pyramid,ptsfa,amdahl,sun,ihnp4}!hoptoad!gnu			  gnu@toad.com
  I forsee a day when there are two kinds of C compilers: standard ones and 
  useful ones ... just like Pascal and Fortran.  Are we making progress yet?
	-- ASC:GUTHERY%slb-test.csnet