> memcpy(void* ptr1, void* ptr2, int n)
Copy n bytes from ptr1 to ptr2. UNDEFINED if ptr1 is NULL or ptr2 is NULL
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It might also have come from a "explicit better than implicit" opinion, as in "it is better to have developers explicitly handle cases where the null pointer is involved
Of course, someone needs to check in the layers of abstraction. The user, programmer, compiler, cpu, architecture.. They chose for the programmer, who like to call themselves "engineers" these days.
>It's pretty much a tiny wrapper around assembler
Assebler has zero problem with adding "null + 4" or computing "null-null". C does, because it's not actually a tiny wrapper.
NULL doesn't exist in assembler, and in C, NULL is only a defined as a macro. It's not something built-in.
C doesn't have any problems adding 4 to NULL nor subtracting NULL from NULL.
#include <stddef.h>
int main() {
if (NULL + 4) {}
if (NULL - NULL) {}
return 0;
}"Having problems" is not a fair description of what's at stake here. The C standard simply says that it doesn't guarantee that such operations give the results that you expect.
Also please note that the article and this whole thread is about the address zero, not about the number zero. If NULL is #defined as 0 in your implementation and you use it in an expression only involving integers, of course no UB is triggered.