Structure deference not working?

Question

Why isn't the following valid?

bool trigger(t_evt evt) const {
    std::shared_ptr<I> ptr = this->instance.lock();

    if (!ptr) {
        return false;
    }

    (ptr->*f)(evt); // -> causes a compilation error

    return true;
}

The error in english is something like that (I don't get it in english):

'->*' : improper usage, left operand of type 'std::shared_ptr<ListenerCardsChange>'

f is a pointer to a member function.

Note that (*ptr.*f)(evt); works fine.

score 1 · Answer 1 · answered Jun 15 '14 at 15:26

1

That's because shared_ptr<T>, and also unique_ptr<T, D>, do not overload operator->*. That's arguably a defect, but I haven't thought about it much and am not 100% sure that there isn't some reason for that.

Use the (*ptr.*f)(evt) syntax.

answered Jun 15 '14 at 15:26

Kerrek SB

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Is ->* a single operator? I though it was operator->(ptr) + operator*(f) – Serge Profafilecebook Jun 15 '14 at 15:37
@SergeProfafilecebook: If only there existed some kind of magic reference that would list C++ operators... (scratch that, then I'd still be creeping around 10k rep) – Kerrek SB Jun 15 '14 at 15:38
@KerrekSB [You mean like this one?](http://en.cppreference.com/w/cpp/language/expressions#Operators) – Casey Jun 16 '14 at 14:18

Structure deference not working?

1 Answers1