Yes, I want the compiler to optimise it away, but I'd like it to do so
without complaining about the "timeout" variable. The following code
has similar problems:
void func(void)
{
return;
{
int timeout;
timeout = 0xFFFF;
while (timeout--);
}
}
Mary-Ann
Ken Jackson wrote:
> I don't know the answer, though I offer an observation.
>
> Most compilers will optimize away the delay that you are
> trying to implement. Therefore you should declare timeout this way:
>
> volatile int timeout;
>
> Also, when I do it that way, I don't get the warning.
>
> -Ken Jackson
>
> Mary-Ann Johnson writes:
> > If I compile the following code (SDCC 2.7.0):
> >
> > ------------------------------------------------
> > void func(void)
> > {
> > int timeout;
> >
> > return;
> >
> > timeout = 0xFFFF;
> > while (timeout--);
> > }
> > ------------------------------------------------
> >
> > SDCC produces the following warnings:
> > "src/test.c:8: warning 84: 'auto' variable 'timeout' may
> > be used before initialization
> > src/test.c:8: warning 84: 'auto' variable 'timeout' may be
> > be used before initialization
> > src/test.c:8: warning 84: 'auto' variable 'timeout' may be
> > used before initialization"
> >
> > Any idea why?
> >
> > And before someone says "Don't call 'return' there!" -
> > this scenario happens when a macro is set to "return" to
> > eliminate the 2nd half of a function.
> >
> > Thanks,
> > Mary-Ann
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