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NM and CM callable. Receives mail from another process.
Process handling (PH) capability is required. Syntax | |
U16 I16V UDS U16V
mailstatus:=RECEIVEMAIL(pin,location,waitflag);
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Functional Return | |
- mailstatus
16-bit unsigned integer (assigned functional return) Returns one of the following values:
| Value | Meaning |
|---|
| 0 | Mailbox empty and waitflag bit (15:1)=0. | | 1 | No message collected, the mailbox contained outgoing
mail from the receiving process. | | 2 | Message collected successfully. | | 3 | Error occurred because an invalid pin was specified
or a bounds check failed. | | 4 | Request denied, waitflag specified that the
receiving process wait for mail if the mailbox is empty, but the
other process sharing the mailbox is already suspended, waiting for mail.
If both processes were suspended, neither could activate the other,
and they may be deadlocked. |
Parameters | |
- pin
16-bit signed integer by value (required) The process sending the mail. If you specify a child process,
pin is the process identification number (PIN) of that
process. If you specify a parent process, pin is zero.
- location
user-defined structure (required) The buffer where the message is written. - waitflag
16-bit unsigned integer by value (required) The action to be taken if the mailbox is empty. This is
determined by the setting of bit (15:1),
which has the following settings:
| Value | Meaning |
|---|
| 0 | Return immediately to the calling process. | | 1 | Wait until incoming mail is ready for collection. |
Operation Notes | |
The RECEIVEMAIL intrinsic lets a process collect mail transmitted
to it by its parent or a child. If the mailbox for the
receiving process is empty, the action taken depends on
the waitflag parameter specified in the RECEIVEMAIL intrinsic
call. If the mailbox is currently in use by another
process, RECEIVEMAIL waits until the mailbox is free before
accessing it. Condition Codes | |
- CCE (2)
Request granted. The mail was collected (value 2 is returned
to mailstatus) or the mail was not collected because the
mailbox contained outgoing mail from the receiving process (value
1 is returned to mailstatus). - CCG (0)
Request denied. An illegal pin parameter (value 3 is returned
to mailstatus). - CCL (1)
Request denied. The location parameter does not allow
write access on the stack address
(value 3 is returned to mailstatus) or because both sending and
receiving processes are waiting for incoming mail, causing a
deadlock (value 4 is returned to mailstatus).
Related Information | |
- Intrinsics
None - Commands
None - Manuals
Interprocess Communication Programmer's Guide (32650-90019)
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