Inter User Communication Vehicle (IUCV) is a data transfer mechanism in IBM VM line of operating systems.
When the other end point also issues the SEVER method, the path is effectively dismantled.
When the interrupt occurs, the information regarding the pending status is made available at the address location specified by the DECLARE BUFFER method.
CP has a specific macro (IUCV) which generates the appropriate code - including the instruction and filling in the IPARML - so that the details regarding the parameters about such and such method can be defaulted or checked for conflict.
Access to some IUCV functions is controlled by statements in the CP Directory (the list of virtual machines and their specifications).
In addition, a virtual machine can impose its own access control by rejecting an attempt to connect.
The CP system services are IUCV end points which are not virtual machines by themselves, but allow a virtual machine to perform hypervisor functions asynchronously or to access specific hypervisor facilities.
Some examples are GCS (The Group Control System) of VM uses IUCV to perform maintenance of shared memory areas between virtual machines.
By using implicit path termination, the GCS recovery virtual machine can ensure that any locks held on the shared area by a virtual machine that entered the group but left unexpectedly is properly released.
VM TCP/IP - the TCP/IP stack for VM - uses IUCV to either allow a virtual machine to perform socket operations or to allow a virtual machine to act as a network interface to pass whole frames or datagrams between itself and the TCP/IP stack.