2 shared pointers tracking the same object [duplicate]

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• std::shared_ptr of this 2 answers

I have the following code (this does not compile straight away as I would need a header and a cpp file to make up for circular dependencies but it gives all the information needed):

#include <memory>
#include <vector>
#include <iostream>

//////////////////////////////////
class MarchingEvent
{
public:
    MarchingEvent() {}

    void myFunction()
    {
        FunctionsHandler::myFunction(std::shared_ptr<MarchingEvent const>(this));
    }
};

//////////////////////////////////
class FunctionsHandler
{
public:
    static std::shared_ptr<MarchingEvent> myFunction( std::shared_ptr<MarchingEvent const> Ein )
    {
        // Do something in Ein.
        return std::shared_ptr<MarchingEvent>();
    }
}

//////////////////////////////////
int main()
{
    std::shared_ptr<MarchingEvent> event = std:make_shared<MarchingEvent>();

    // Some other code.
}

Now FunctionsHandler::myFunction() takes a shared pointer as argument, so I create a shared pointer out of this when calling the function in MarchingEvent::myFunction().

So it turns out there are 2 series of shared pointers following the same MarchingEvent object, because I create a 2nd shared pointer out of this. So obviously the MarchingEvent gets destroyed (and a crash occurs) when returning from FunctionsHandler::myFunction().

So how can I let this know about the shared pointer tracking it? So as not to create a 2nd one...