Error with Google Mock and shared_from_this?

Question

I'm getting the following error thrown in a test of mine:

unknown file: error: C++ exception with description "tr1::bad_weak_ptr" thrown in the test body.

Stepping through the test one line at a time I can see the exception is being thrown on a line where I call:

MyClassSharedPointer myClassPointer(shared_from_this());

I need a pointer to the object the code is executing in, because I need to set the object up as an observer of one of it's members (using boost::signals to implement the observer). The code appears to work fine while normally executing but from my test code I get this error.

Answer 1

The problem was that in my production code the myClass object is referenced as a shared_ptr whereas in my test code I had mistakenly declared the myClass object as a naked pointer. Which explains why shared_from_this() wasn't working... because this wasn't actually a shared_ptr.

Answer 2

For me the issue was that myClass did not have a shared_ptr prior to shared_from_this being called (it was being used in a unique_ptr). And shared_from_this requires that at least one shared_ptr must already have been created. See also this answer.