HP 3000 Manuals HP 3000 Manuals
Mail Transfer Process
The transfer of mail is based upon a transaction between the sending and
receiving processes that involves the following steps:
1. The sending process tests the mailbox to determine its status,
that is, whether it is empty, contains a message, or is being used
by the receiving process (optional).
2. The sending process transmits the mail to the mailbox. The
message transferred is an array of halfwords in the sending
process stack, defined by starting location and word count. The
smallest message allowed is a single word. MPE XL automatically
performs a bounds check to ensure that the array specified
actually falls within the limits of the process stack.
3. The receiving process may test the mailbox to determine its status
(optional).
4. If the mailbox contains a message, the receiving process collects
this mail. MPE XL performs another bounds check to validate the
address given for the stack of the receiving process. If the mail
is not collected before new mail is sent, any additional mail from
the sending process will overwrite it.