C# prototype of C: void**

Question

I want to access a function implemented in a C-dll with the following prototype: rval = imgSnap(SESSION_ID sid, void** bufAddr) Now: 1. How would the "void** bufAddr" part look like in the corresponding C# prototype? 2. How do I call this C# method? (rval is uint, sid is int). "bufAddr" exists allready, it must not be allocated, and I don't want to copy data. imgSnap shall simply write its half a million bytes from &&bufAddr on. Any idea?