alignof – Tarik Billa

What’s the difference between sizeof and alignof?

July 9, 2023 by Tarik

Well, “memory” is basically a huge array of bytes. However, most larger things like integers need more than 1 byte to store them — a 32 bit value, for example, would use 4 consecutive bytes of memory. Now, the memory modules in your computer aren’t usually “bytes”; they are also organized with a few bytes … Read more

Is it always the case that sizeof(T) >= alignof(T) for all object types T?

May 22, 2023 by Tarik

At least in standard C++, for anything you can make an array of (with length > 1), this will have to be true. If you have Foo arr[2]; and alignof(Foo) > sizeof(Foo), then arr[0] and arr[1] can’t both be aligned. As Zalman Stern’s example shows, though, at least some compilers will allow you to declare … Read more