Doing this from memory - sorry, cannot find a source reference (which would be the ideal authority for your question). Given some of the grey hair now showing on my head, I have to ask - what device do you have open and are calling a seek() against? If it were an old tape drive (perhaps even new ones?) or other sequential access medium, you would need to seek to the beginning of file then to the position. Given a random access medium, you can "simply" (with a bit of additional housekeeping around buffers and such) reset the current file pointer on the handle. So, "It Depends™". [update] Additionally, some devices do not allow seeking backwards and will throw an error if attempted.
