Mail Transfer Process

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).

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/iX automatically performs a bounds check to ensure that the array specified actually falls within the limits of the process stack.

The receiving process may test the mailbox to determine its status (optional).

If the mailbox contains a message, the receiving process collects this mail. MPE/iX 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.