Where is the race?

Hi guys!

I am trying to encapsulate into tasks a C library that has a bunch of callbacks. The real code can't be pasted here, so I'll make a fake example. I would like to encapsulate the async request state in a class together with a task_completion_event. The request object would kill itself when the work is complete.

Please can you help me understand why this race happens and maybe give me any suggestion of alternative designs? I get spurious crashes running the code below.

Thank you very much for the attention!!!

Best regards

Mello

#include <iostream>
#include <memory>
#include <ppltasks.h>
#include <Windows.h>

using namespace std;
using namespace concurrency;

class Request : public enable_shared_from_this<Request>
{
shared_ptr<Request> m_selfReference;
task_completion_event<void> m_completionSource;

void AcquireSelfReference()
{
m_selfReference = shared_from_this();
}

void ReleaseSelfReference()
{
m_selfReference = nullptr;
}

public:
~Request()
{
//cout << "~Request " << ::GetCurrentThreadId() << endl;
}

task<void> ExecuteAsync()
{
AcquireSelfReference();

// do async work
task<void> t([this]()
{
cout << "async " << GetCurrentThreadId() << endl;
m_completionSource.set();
});

return task<void>(m_completionSource).then([this]
{
ReleaseSelfReference();
});
}
};

task<void> DoAsyncWork()
{
shared_ptr<Request> pRequest(make_shared<Request>());
return pRequest->ExecuteAsync();
}

int main()
{
cout << "start " << GetCurrentThreadId() << endl;
for (int i = 0; i < 10000; i++)
{
DoAsyncWork().get();
}

 return 0;
}