> On Mon, Jul 16, 2007 at 02:39:39PM -0000, Wolfram Gloger wrote: > > > int *p; > > > p = malloc (4); > > > *p = 0; > > > p = realloc (p, 4); > > > *p = 1; > > > > By that reasoning, consider: > > > > int *p; > > p = malloc (4); > > *p = 0; > > free(p); > > p = malloc (4); > > *p = 1; > > Except that in the first sequence, the value of *p is retained across > the reallocation, so "*p = 0" is not dead. The two examples aren't > really the same at all.
I'm not saying they are the same. But, how does gcc determine that it can move "*p = 0" after realloc()? Does it treat realloc() specially and insert a run-time check to look at its result to compare it with the old pointer? That would seem like a dubious feature totally independent of __attribute_malloc__. Surely you agree that in my second example, "*p = 0" _cannot_ be moved after the call to destroy_something_and_allocate_anotherthing(p)? Regards, Wolfram.
