Warning Behavior

Warning Behavior

[Ivan Novick]

Hello,

How come the following code would not be considered a Warning?

Surely there is no possible way this would be intentional?

if (x<4);
	x++;

Cheers,
Ivan

Re: Warning Behavior

[Paolo Bonzini]

Ivan Novick wrote:
> Hello,
> 
> How come the following code would not be considered a Warning?
> 
> Surely there is no possible way this would be intentional?
> 
> if (x<4);
> 	x++;

When you consider macro expansion, it could:

#if SIZEOF_LONG == 4
#define WARN_FOR_BIG_VALUES \
   printf ("hey, x is too big, keeping low bits only!")
#else
#define WARN_FOR_BIG_VALUES /* nothing */
#endif

...

long f (long long x)
{
   if (x > LONG_MAX)
     WARN_FOR_BIG_VALUES;

   return x & LONG_MAX;
}

(I'm not saying this is good code).

Paolo

Re: Warning Behavior

[Andreas Schwab]

Ivan Novick <Ivan.Novick@makoglobal.com> writes:

> How come the following code would not be considered a Warning?

Try -Wextra.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: Warning Behavior

[jlh]

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Andreas Schwab wrote:

> Try -Wextra.

Ah thanks!  I have already lost time several times due to this
almost invisible mistake and I didn't know -Wextra would catch it.
However, it seems to only work for the C compiler, not for C++.

(Using GCC 3.4.4)

(Oops, sorry Andreas, I actually meant to only send the message
to the list)

jlh


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