CODEWITHSUNDEEP
c++c++14
CoffeeTableEspresso
CoffeeTableEspresso

Reputation: 2652

prevent `sizeof` operator being called for a complete type in C++14

In C++, you can prevent a function from being used on T using the = delete syntax. You can't call sizeof using an incomplete type.

However, I was wondering, is there a way to prevent sizeof from being used on a complete type?

My initial attempts went something like this:

size_t operator sizeof(T) = delete;

Which obviously didn't work.

Now, from research online, I wasn't able to find anything suggesting that it was possible to prevent sizeof from being used on a type, unless that type was incomplete.

So, is there any way to prevent the sizeof operator from being used with a class (either using the = delete syntax or otherwise), that results in a compile-time error?

Anything is appreciated, no matter how hacky, and a solution that works most of the time is fine, too. C++14 compatible and no external libraries, though.

Upvotes: 0

Views: 185

Answers (1)

kriss
kriss

Reputation: 24177

Unlikely. sizeof is not a function, it's a builtin operator. As it's necessary under the hood for the correct behavior of new (memory size to allocate for some object), I can't see how you could remove it.

But if the goal is to hide implementation size you could add some indirection layer and hide the actual type behind some facade of fixed size, but it wouldn't be a zero cost abstraction.

Upvotes: 3

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