Passing non-static member function as std::function

Question

I have a similar situation:

class A {
    void callingFunction() {
      calledFunction(passedFunction);
    }

    void calledFunction(std::function<void(int)> foo) {
    }

    void passedFunction(int arguments) {
    }
};

The compiler error is

error: invalid use of non-static member function

How do I achieve this without making the passedFunction static?

Doing this:

calledFunction(std::bind(&A::passedFunction, this);

Creates this error:

error:static assertion failed: Wrong number of arguments foor pointer-to-member

Does it mean I have to provide all the arguments in the callingFunctionwhen passing the passedFunction? This is not possible as the arguments for the passedFunction are specified in the calledFunction

songyuanyao · Accepted Answer · 2018-05-21T12:42:12.633

1

You can write a lambda capturing this, on which passedFunction could be called.

calledFunction([this](int v) { this->passedFunction(v); });

edited May 21 '18 at 12:42

answered May 21 '18 at 12:38

songyuanyao

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Yes, but note that depending on what you do with the `std::function`, it's possible to get a `std::function` containing the `A*` pointer which was captured as `this` to live past the lifetime of the `A` object, so be careful about lifetimes. – aschepler May 21 '18 at 12:40
This works thank you. – skluzada May 21 '18 at 12:56

Passing non-static member function as std::function

1 Answers1