z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

Description
ipcs writes to the standard output information about active interprocess
communication facilities. If you do not specify any flags, ipcs writes information in a
short form about currently active message queues, shared memory segments, and
semaphores.
The column headings and the meaning of the columns in an ipcs command listing
are listed in Table 14. The letters in parentheses indicate the command flags that
cause the corresponding heading to appear. (all) means that the heading is always
displayed. These flags determine what information is provided for each facility. They
do not determine which facilities are listed.
Table 14. Explanation of the ipcs Command Listing
Column Heading Meaning of the Column
T
(all except y)
ID
(all except x,w,y,S,B)
KEY
(all except y,S,B)
MODE
(all except x,w,y,S,B)
The type of facility:
q Message queue
m Shared memory segment
s Semaphore
S Map Memory Service
The identifier for the facility entry
The key used as a parameter to the msgget subroutine, the
semget subroutine, or the shmget subroutine to make the
facility entry. (The key of a shared memory segment is
changed to IPC_PRIVATE when the segment is removed
until all processes attached to the segment detach it.)
The facility access modes and flags. The mode consists of
11 characters that are interpreted as follows:
The first two characters can be the following:
R If a process is waiting in a msgrcv() system call.
S If a process is waiting in a msgsnd() system call.
D If the associated shared memory segment has
been removed. It disappears when the last process
attached to the segment detaches it.
The next nine characters are interpreted as three sets of
three characters each. The first set refers to the owner’s
permissions; the next to permissions of others in the user
group of the facility entry; and the last to all others. Within
each set, the first character indicates permission to read,
the second character indicates permission to write or alter
the facility entry, and the last character is currently unused.
The permissions are indicated as follows:
r If read permission is granted
w If write permission is granted
a If alter permission is granted
– If the indicated permission is not granted
OWNER (all, except S,B) The login name or user ID of the owner of the facility entry.
GROUP (all) The name or group ID of the group that owns the facility
entry.
CREATOR (a,c) The login name or user ID of the creator of the facility entry.
ipcs
Chapter 2. Shell command descriptions 321