Re: NSK(OSS) compilation problem

[Matthew Woehlke]

Paul Eggert wrote:
> Matthew Woehlke <address@hidden> writes:
> > This simple test is OK on my Linux box and on NSK without -O. It does
> > not work /AT ALL/ (100% failure rate) on NSK with -O.
>
> OK, but the C standard does not require that it has to work, because
> it doesn't say what happens when you shift a negative integer right.
> So the test program is too strict.

Eh? How is testing if ((1<<1)>>1) == 1 "too strict"? This fails. So do 
(1<<2)>>2, (1<<3)>>3, ..., (1<<62)>>62, none of which involve negative 
numbers...

In fact...
1<<1 seems to be 576460752437645312
576460752437645312>>1 seems to be 154618822656
1<<2 seems to be -9214821626686108448
-9214821626686108448>>2 seems to be 163208757248
...
Eek!

btw, was I supposed to see something different from your version? It is 
admittedly much more platform-agnostic (I wasn't trying :-)), but I 
didn't see anything that would cause me to expect yours to give 
different results.

> What happens if you use the following test program instead?  That is,
> what is the output of this program, and its exit status?  (Also,
> assuming it outputs something and fails, what happens if you omit the
> printf?  Does it still exit with status 1?)

(Using 'echo $?' in all cases...)
With the printf I get:
shift 1 failed
1

Without the printf I get:
1

Without using -O, all is well of course:
0

--
Matthew
"Try to bring it back in one piece this time." -- Q (MI6)