Initializing an array with NULL pointer with GCC throw error

I am using GCC and IAR to compile some C code.

#include <stdio.h>#include <stdint.h>#include <stddef.h>uint8_t tab[] = NULL;

this exmple code throw this error with GCC : error: invalid initializer

With IAR compiler the syntax is accepted

What is wrong here with GCC and why it is accepted by IAR compiler?