HP 3000 Manuals HP 3000 Manuals
MAIL
NM and CM callable.
Determines the status of the mailbox used by its parent or child.
Process handling (PH) capability is required.
Syntax
_____________________________________
| |
| U16 I16V I16 |
| mailstatus:=MAIL(pin,length); |
_____________________________________
Functional Return
mailstatus 16-bit unsigned integer (assigned functional
return)
Returns the status of the mailbox:
Value Meaning
0 Mailbox empty.
1 Contains previous outgoing mail from this calling
process that the destination process has not yet
collected.
2 Contains incoming mail awaiting collection by this
calling process. The length of the mail is returned
in length.
3 An error occurred, an invalid pin was specified, or a
bounds check failed.
4 Temporarily inaccessible, other intrinsics are using
it in the preparation or analysis of mail.
Parameters
pin 16-bit signed integer by value (required)
Passes the mailbox to be tested. If pin specifies
the mailbox of a child process, it must be the
process identification number (PIN) of that child.
Zero specifies the mailbox of a parent process.
length 16 bit signed integer by reference (required)
Returns the length, in half words, of any incoming
mail in the mailbox.
Operation Notes
If the mailbox contains mail that is awaiting collection by this process,
the length of this message (in half words) is returned to the calling
process in the length parameter. This enables the calling process to
initialize its stack in preparation for receipt of the message.
Condition Codes
CCE (2) Request granted. The mailbox mailstatus was
tested.
CCG (0) Request denied. An illegal pin parameter was
specified. The value of 3 is returned to the
calling process through mailstatus.
CCL (1) Request denied. The length parameter defines stack
address that does not have write access.
Related Information
Intrinsics None
Commands None
Manuals Interprocess Communication Programmer's Guide
(32650-90019)