How do I cast a function with a derived argument to a function with a base argument?

Question

I have a class named Reciever that has a function called recieve(const Event *), where Event inherits from BaseEvent. I want to create a bind to a specific instance of that class. The instance is called rec. To do this I use:

void(Reciever::*func)(const Event *) = &Reciever::recieve;
auto recievePtr = std::bind(func, &rec, std::placeholders::_1);

However, when I try to store this in a vector, I have to specify an std::function that takes a BaseEvent as the input, not an Event, like so:

std::vector<std::function<void(const BaseEvent*)>>

How can I cast recievePtr so I can store it properly in the vector? Is this even possible? The issue with using a function pointer to a BaseEvent is that the Reciever can have multiple recieve() methods with different derived classes all based on BaseEvent

Answer 1

You can try something along the following. This compiled and ran fine on my machine. Visual Studio targeting platform toolset v120.

Reciever rec;

std::vector<std::function<void(const BaseEvent*)>> vector;

vector.push_back(
    [&rec](const BaseEvent* event)
{
    rec.recieve(static_cast<const Event*>(event));
});

vector.push_back(
    [&rec](const BaseEvent* event)
{
    rec.recieve(static_cast<const EventD*>(event));
});

const BaseEvent* e = new Event();
const BaseEvent* d = new EventD();

vector[0](e);
vector[1](d);