>> Many folks try and cast ptr to volatile, but that's an abuse because >> GCC considers volatile something for memory mapped hardware. Volatile >> should not be used in an attempt to tame the optimizer. > > GCC does not consider volatile to be something for memory mapped > hardware. OK, this appears to be creating a moving definition (or the definition has changed since I took note of it). I took the last definition from Ian Lance Taylor. See http://www.airs.com/blog/archives/154 and, for example, https://gcc.gnu.org/ml/gcc-help/2012-03/msg00257.html. > ... > If you don't mind being nonportable, a memoryclobber should do it: > > memset(ptr, 0x00, n); > asm volatile("": : : "memory"); > > or even: > > memset(ptr, 0x00, n); > __atomic_thread_fence(__ATOMIC_RELAXED); Perfect, thanks. Jeff
