1const expect = @import("std").testing.expect;
 2
 3test "optional pointers" {
 4    // Pointers cannot be null. If you want a null pointer, use the optional
 5    // prefix `?` to make the pointer type optional.
 6    var ptr: ?*i32 = null;
 7
 8    var x: i32 = 1;
 9    ptr = &x;
10
11    try expect(ptr.?.* == 1);
12
13    // Optional pointers are the same size as normal pointers, because pointer
14    // value 0 is used as the null value.
15    try expect(@sizeOf(?*i32) == @sizeOf(*i32));
16}
17
18// test