On Fri, Mar 10, 2017 at 11:57:28PM +0800, Liu Hao wrote: > >So does this mean, that the above C code uses undefined behavior? > Yes. > > 6.2.4 Storage durations of objects > 1 ... Allocated storage is described in 7.22.3. > 2 ... The value of a pointer becomes indeterminate when the object it > points to (or just past) reaches the end of its lifetime. > > 7.22.3 Memory management functions > 1 ... The lifetime of an allocated object extends from the allocation > until the deallocation. ... But a null pointer does not point to an (allocated) object. So the code has undefined behaviour only if ever the pointer is not a null pointer? What a mess :-) Segher
