Pet peeve alert: sizeof is not a function. It's a unary operator. The parenthesis you usually see after it are part of the argument, which for type names looks

Pet peeve alert: sizeof is not a function. It's a unary operator. The parenthesis you usually see after it are part of the argument, which for type names looks like a cast to the type in question. Like any other cast, the syntax is the type name in parenthesis. Apologies if you already knew this.