Xref: utzoo comp.lang.c:22135 comp.unix.ultrix:1757
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From: penneyj@servio.UUCP (D. Jason Penney)
Newsgroups: comp.lang.c,comp.unix.ultrix
Subject: Type of expression sizeof(x)
Summary: (DECStation 3100 bug) Is it Unsigned?
Message-ID: <256@servio.UUCP>
Date: 19 Sep 89 21:28:06 GMT
Reply-To: penneyj@servio.UUCP (D. Jason Penney)
Organization: Servio Logic Development Corp.; Beaverton, OR
Lines: 29

Consider the following simple program?
#include <stdio.h>

main()
{
if (3 - sizeof(long) < 0)
  printf("passed\n");
else
  printf("failed\n");
}

On our DECStation-3100 running Ultrix, this program returns "failed" instead
of "passed".  It seems that the sizeof() is promoting the expression to be
unsigned.  By the way, changing 3 to 3L does NOT make the problem disappear.

I am posting this quirk to comp.lang.c because I would be VERY interested to
hear (by e-mail, please) from anyone who thinks that this is acceptable 
behavior.

I am posting this to comp.unix.ultrix because I think you poor implementors
ought to be forewarned.

Our conversation with DEC re this bug was extremely unhelpful.  They claim that
the return type of a sizeof() expression is system-dependent.
-- 
D. Jason Penney                  Ph: (503) 629-8383
Beaverton, OR 97006              uucp: ...uunet!servio!penneyj
STANDARD DISCLAIMER:  Should I or my opinions be caught or killed, the
company will disavow any knowledge of my actions...