[Valgrind-developers] Client callback offsets for skins

[Jeremy F. <je...@go...>]

At the moment, not many skins have client callbacks (only memcheck, I
think).  However, if other skins follow memcheck's example of starting
callbacks at VG_USERREQ__FINAL_DUMMY_CLIENT_REQUEST + 1, they will all
end up with overlapping numbers.

This means that if a particular program under study has callbacks for
different skins, they will end up doing the wrong thing if run with the
wrong skin.  It seems to me that there needs to be a systematic way for
skins to distinguish their callback numbers from each other.  Maybe
encode some kind of skin ID into the top 16 bits of the request number?


    J