Real and effective userids.

[Dave Mielke]

In article <1219 at virtech.UUCP> cpcahil at virtech.UUCP (Conor P. Cahill) writes:
>The real userid is the numerical id of "the user"
>that is running a process, as opposed to "the effective" id of the process
>that is used to determine whether you can open, create, unlink, etc. a file.
This is intuitively the way things should work, but when I open a file
from within a setuid program it appears to enforce the access rights of
the real userid and not those of the effective userid. Why is this?