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Discussion on: Type/pointer cheatsheet

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Karsten Schmidt Author

Maybe slightly unclear wording from my side on that extern section! I meant to say: optionals are only supported if in pointer form, but not as optional values, i.e. *?u8 or ?*u8 is supported, but ?u8 isn't. That didn't mean to imply that all pointers must be optional! Normal pointers are supported of course... Makes sense?

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orent

What is the logic behind this restriction? Something about the representation of non-pointer optionals?

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Karsten Schmidt Author

I'd think it's because there's no concept of optional values in C, yet optional pointers can be represented in the same amount of space (using 0 as indicator for a null pointer), whereas optional non-pointer values take up extra bytes, e.g. a ?u8 is actually 2 bytes, a ?u16 is 4 bytes, a ?u32 is 8 bytes...

An argument could be made that by that logic slices shouldn't be supported either (but they are), so I really don't know the reasons... :)