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A process sends mail to its parent or child
with the SENDMAIL
intrinsic. If the mailbox for the receiving process contains a
message sent previously by the calling process but not collected
by the receiving process, the action taken depends on the
waitflag parameter specified in SENDMAIL. For example, to send mail to its parent, the following intrinsic
call could be used:
STAT:=SENDMAIL(0,3,LOCAT,WAITSTAT);
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The parameters specified are: - pin
0, specifying that the mail is to be sent to the parent process. - count
3, specifying that the length of the message is three halfwords. - location
LOCAT, an unsigned integer array with the address of the buffer in the stack containing the message to be sent. - waitflag
WAITSTAT, a 16-bit unsigned integer by value. If bit (15:1)=0, any mail sent previously will be overwritten. If bit (15:1)=1, the intrinsic will wait until the receiving process collects the previous mail before sending the current mail.
The status returned to STAT is one of the following values: - Status
Meaning
- 0
The mail was transmitted successfully. The mailbox contained no previous mail. - 1
The mail was transmitted successfully. The mailbox contained previously sent mail that was overwritten by the new mail, or contained previous incoming/outgoing mail that was cleared. - 2
The mail was not transmitted successfully because the mailbox contained incoming mail to be collected by the sending process (regardless of the waitflag parameter setting). This means that the mailbox currently contains mail sent to the would-be sending process, and the sending process must collect this mail before it can send any itself. - 3
An error occurred because an illegal pin was specified or a bounds check failed. - 4
An illegal wait request would have produced a deadlock. This means that mail has been sent to the would-be sending process, and the sender is waiting for a reply. - 5
The request was rejected because the count specified in the count
parameter exceeded the mailbox size allowed by the system. The maximum size cannot exceed the maximum DST size for the system. - 6
The request was rejected because storage resources for the mail data segment were not available.
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