Re: [avr-gcc-list] OT Generic C question

[David Brown]

----- Original Message -----
From: "Trampas" <address@hidden>
> I was helping a friend debug some code, he is new to C,  using the Keil
> version of GCC for ARM. Anyway I found the following:
>
> int i;
>
> i=0;
> i=i++;
> //i was still zero that
>
> That is i=i++ never incremented i, now I would have thought the line would
> be the same as:
>
> i=i;
> i=i+1;
>
> So you guys are the smartest people I know when it comes to C so I thought
I
> would ask you guys if this is a compiler bug or is my understanding of C
> just been shaken.
>
> Regards,
> Trampas
>
>

I'd agree with you that i should be 1 after "i = i++", despite the sillyness
of the statement.  However, how did you check that i was still 0?  If the
compiler had no reason to actually carry out the incrementation, and you
used a debugger to view "i", then it's quite likely that it remained at 0
due to legitimate compiler optomisations.