Pointers in Zig

Reilly,3/13/2026•zig systems

A variable stores a value.

For example:


var a: usize = 1;
const b = a;
a = 2;

just like in js:


a == 2;
b == 1;

But imagine we had this use case: we want b to always stay in sync with a. That is, we want to refer to a itself rather than a’s value.

We could manually update b every time we update a.

But what if, instead of copying a’s value, we could have b reference a directly?

That’s what pointers let us do!

A pointer is a value that stores an address.

Zig is statically typed, a pointer’s type also describes what it points to (pointee).

Here’s a more concrete example of creating a pointer.


var a: usize = 2;
const b = &a; // b is *usize (a pointer to an unsigned integer type)

2 obvious things:

So we can change a’s value, but we can’t change b’s. But there is a way to change a through the pointer b

Wait, how?

We can access and mutate the value at the address the pointer stores by dereferencing it with .*.


var a: usize = 2;
const b = &a;
b.* = 3;

You might be thinking: “but if b.* = 3, doesn’t that mean b changed?”

The reason it doesn’t is because b still stores the same address: the address of a.

What changed was the value stored at that address.

In other words, b points to a’s storage location, not to the number 2 or 3.

Now here’s the same example, but let’s make a immutable:


const a: usize = 2;
const b = &a;
b.* = 3; //error: cannot assign to constant

This fails because b is now pointing to immutable data.