Re: [Xenomai-help] native heap services and overloading new

[Philippe Gerum <rpm@xenomai.org>]

On Wed, 2006-08-02 at 21:09 +0200, Jan Kiszka wrote:
> Brandt Erickson wrote:
> > I have some code where I'd like to be able to dynamically allocate memory
> > in realtime.  Since the code is written in C++, I was thinking of just
> > making a huge global RT_HEAP and overloading the new and delete operators
> > to use the rt_heap_alloc and rt_heap_free functions.  First off, I'm
> > wondering if there are any caveats to this sort of thing that wouldn't be
> > obvious to someone new to xenomai like myself.  Second, if I fail to call
> > rt_heap_delete before the program terminates, does the heap remain
> > registered hang potentially causing problems when I try to re-allocate the
> > heap when the program is run again?  Thanks.
> 
> For now: yes, the heap will stay, no automatic cleanup (the posix skin
> already have this). You could then run into naming conflicts and you
> lose memory, of course.
> 
> But you could install some signal handler for cleaning up. We do so in
> our native-skin-based framework (also C++, but no "evil" ;) features in
> use). We even catch SIGSEGV this way.
> 

Another simple option: the binding operation is particularly useful for
recycling/discarding lingering objects.

RT_HEAP app_heap;

void init_heap (void)
{
	RT_HEAP old_heap;

	if (rt_heap_bind(&old_heap, "foo", TM_NONBLOCK) == 0)
		rt_heap_delete(&old_heap);

	rt_heap_create(&app_heap, "foo", ...);
}

-- 
Philippe.