由于指针算术是在同一个数组中定义的,我怀疑我们是否可以NULL
从另一个NULL
. 我担心以下方面的实施:
//first and second can both either be from the same array
//or be both NULL
prtdiff_t sub(void *first, void *second){
//Do I really need this condition?
if(!first && !second)
return (ptrdiff_t) 0;
return second - first;
}