C :: Setting Values To Pointers

This function below takes a pointer as an argument. What I expect to happen is, since expr++ has higher precedence than *expr, that is, the primary expression operators have higher precedence than the unary operators, pointer arithmetic should occur where we increment to the second address pointed to by dbuf, and then we should dereference the value at that address. Given that logiv, when i print dbuf[3] it should print the value pointed to at the 4th address in dbuf. However, the value it returns is 0x0 not 0x3. Why doesn't it dereference the value 0x3?

Code: void dfill(unsigned char *dbuf)
{
dbuf = (unsigned char*)malloc(4);
memset(dbuf, 0, 4);
*dbuf = 0x0;
*dbuf++ = 0x1;
*dbuf++ = 0x2;
*dbuf++ = 0x3;
printf("dbuf val: 0x%x
", dbuf[3]);
}