clSetMemObjectDestructorCallback calls callback with invalid mem_obj

Hi everyone,

I wrote a little wrapper for clMemoryObjects in which I set a callback for buffer/memory destruction via clSetMemObjectDestructorCallback (actually it's the C++ wrapper equivalent).

When the callback is called, however, and I want to query the cl_mem, which is passed to the callback by the API, I sometimes get an error code Of "-38" -> CL_INVALID_MEM_OBJECT. The application is basically single threaded, so I don't see, where the object should have been destroyed elswhere.

I am also using other OpenCL platforms, in which the code workd properly, so I'm wondering where to look next for my bug.

Best regards

Matthias