On 03/12/17 02:14, Andrew Makhorin wrote: >> No, that is not how it works. 6.2.4/2 says: [...] "The value of a >> pointer becomes indeterminate when the object it points to (or just >> past) reaches the end of its lifetime." >> >> It does not matter whether the value of p changes in *your* system, >> or in most systems. Using the value of p after deallocating the object >> it pointed to is undefined behaviour. >> > > Does this mean that the following fragment is invalid? (I think it > isn't.) > > void *p, *q; > p = malloc(123); > q = p; > free(p); > if (p == q) ... > > Thanks. > Yes, as well as this: char *p, *q; p = malloc(123); q = p + 123; free(p); if (q == p + 123) ... Bernd.
