Thanks for feedback.

Could you please specify your working environment:
- what test-code do you use, dcraw_emu (or something else from LibRaw's samples)
- or your own code

Possibly, the source of error is:
1) LibRaw_file_datastream() constructor saves the pointer to filename you pass to LibRaw::open_file()
Note, the pointer is stored, not string copied!

2) the buffer with filename (passed to open_file) is destroyed before LibRaw::unpack() called