[webkit-dev] Do we have a style preference about const member functions?

Yong Li yong.li.webkit at gmail.com
Thu Jun 2 07:56:15 PDT 2011

I think we should add a rule like "a const member function should
never return non-const pointer/reference".

I have seen the problem in many places that you can get non-const
reference on a const object.

For example, InlineTextBox has

InlineTextBox* prevTextBox() const;
InlineTextBox* nextTextBox() const;

Assume you have a function: void myFunction(const InlineTextBox* textBox)

When the text box has a sibling, you can easily get a non-const
pointer by calling textBox->nextTextBox()->prevTextBox(), which sounds

2011/5/31 Geoffrey Garen <ggaren at apple.com>:
>>>> Even in a class that is used in a tree, I still think simple member variable accessor methods (that do not return tree neighbors)  should be const.
>>> OK. Why?
>> Because it indicates to me and the compiler, that the method doesn't have side effects.
> A const member function can have side effects. It can modify any global state outside the object. It can also modify sub-objects inside the object, and return non-const references to sub-objects and related objects that might be used to produce side-effects at any time.
> It's exactly statements like this that make me think that const member functions are a bad idea -- people think they provide a guarantee, but they don't.
> Geoff
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