VMGROUP(join_user{=0},(8,vmname)==>c;VMCOMM) Join VM Group

A new VCOMM is created and associated with name "vmname". vmname is the name of the virtual machine joining the group.

The maximum number of IUCV paths allowed for the virtual machine is initially four. See order code 2 to change this.

Initially the virtual machine is not authorized to send priority messages. See order codes 6 and 7 to change this.

Initially the maximum number of outstanding messages allowed on any IUCV path to the virtual machine is unspecified. See order code 8 to change this.

Return codes:

0 - VM has joined the group. VMCOMM is the communication key for that VM's CP simulator. (The vmname may have already been in the group, but is not logged on.)

1 - vmname already logged on. VMCOMM is DK0.

vmname is the name of the virtual machine to be quit from the group. The VMCOMM associated with vmname is destroyed.

Return codes:

0 - VM has been quit.

1 - vmname not a member of the group.

If the maximum number of paths is decreased below the number currently established, no new paths may be established until the number is below the limit. Existing paths are not severed.

{ni}VMGROUP(no_priority_iucv{=7},(8,vmname)==>c) Forbid IUCV Priority communications

Any existing paths which are authorized for priority communications remain authorized until they are severed.

A value of 0 in msglim indicates that the message limit is unspecified.

VMGROUP(kt==>X'1234567A')

Internal Logic

The group manager domain maintains three keys in a record collection for each username. These are the user's VM communication key, the user's queue domain key, and the CP simulator Group Communication key.

One of these records contains the count of active IUCV paths, and whether an IUCV buffer is declared.

When a new vm user is joined to the group, the group manager first checks if there is a CP Simulator Group Communication key registered under that name. If there is and it is not DK0, then return code 1 is returned. Otherwise, if there is already a VMCOMM key for that name, it is returned. Otherwise a VMCOMM object is built, the VMCOMM and queue keys are registered in the record collection, and the VMCOMM key is returned with rc=0.

When a user is quit his records are deleted from the record collection, and his VMCOMM object is destroyed.