HP 3000 Manuals HP 3000 Manuals
Chapter 3 Deadlock Considerations
Simultaneous use of mail transmission, process suspension, and
RIN-locking intrinsics throughout a process structure could result in a
deadlock if the intrinsic calls are not synchronized properly. MPE XL
ensures that deadlock between different jobs/sessions cannot occur as
long as none of the processes have Multiple RIN (MR) capability. Be
aware of the following:
* In a multiprocess job/session, whenever a process is suspended
(through the SUSPEND intrinsic, or when locking a RIN or receiving
mail), MPE XL does not determine whether or not all other processes
in the tree are suspended. Avoid this situation.
* An attempt by a process to lock a global RIN succeeds only if both of
the following conditions are met:
* No other process within the job/session currently has locked this
RIN. A global RIN cannot be used as a local RIN, because deadlock
within the same job/session can occur.
* The calling process currently has no other global RIN locked for
itself. This could otherwise result in deadlock between two
jobs/sessions.
For more information concerning the use of RIN-locking intrinsics refer
to Resource Management Programmer's Guide (32650-90024).