A/UX® Programmer's Reference

intro(2) intro(2)
Tty Group ID
Each active process can be a member of a terminal group that is
identified by a positive integer called the tty group ID. This
grouping is used to terminate a group of related processes upon
termination of one of the processes in the group (see exi t(2) and
signal(3».
Session
Each process group is a member of a session. A process is considered
to be a member of the session of which its process group is
a member. A newly created process joins the session membership
(see setsid(3P». Multiple process groups may be in the same
session (see setpgid(3P».
Session Leader
A process that has created a session (see set sid(3P».
Controlling Terminal
A terminal that is associated with a session. Each session may
have at most one controlling terminal associated with it, and a
controlling terminal is associated with exactly one session (see
termio(7P».
Controlling Process
The session leader that established the connection to the controlling
terminal.
Foreground Process Group
Each session that has established a connection with a controlling
terminal has exactly one process group of the session as the foreground
process group of that controlling terminal. The foreground
process group has priveleges, when accessing its controlling terminal,
that are denied to background process groups (see
termios(7P».
Background Process Group
Any process group that is a member of a session that has established
a connection with a controlling terminal that is not in the
foreground process group.
Real User ID and Real Group ID
Each user allowed on the system is identified by a positive integer
called a real user ID.
Each user is also a member of a group. The group is identified by
a positive integer called the real group ID.
February, 1990
Revision C
11