Re: [Jack-Devel] Stack preallocation issues

On Tue, Mar 15, 2011 at 04:24:01PM +0200, Sampo Savolainen wrote:

> Volatile sounds like a good idea. This
> 
>  memset(&foo + ASSUMED_MEMSET_STACK_SIZE, 0, JACK_THREAD_STACK_TOUCH -
> ASSUMED_MEMSET_STACK_SIZE);
> 
> should work as well. Volatile is however much more elegant if it indeed
> works as assumed with all compilers.

It's two separate issues really.


AFAICS, somehting like this should work:

void touch_stack (void)
{
    volatile char [STACK_SIZE] p;
    int i;

    for (i = 0; i < STACK_SIZE); i += STEP) p [i] = 0;
}


void thr_main (...) // library code executed in new thread
{
// any local data required

   touch_stack ();

// put thread in RT mode

    user_thr_main (arg)
}


* local data in thr_main() is not touched.
* the compiler can't ignore 'volatile' and remove the p [i] = 0.
* touch_stack() and user_thr_main() have the same stack space.

Ciao,

-- 
FA

1300203877.27657_0.ltw:2,a <20110315154410.GB17058 at linuxaudio dot org>