Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (F)
Guardian Procedure Calls Reference Manual—522629-013
5-107
FILE_GETRECEIVEINFO_ Procedure
receive-info output
INT .EXT:ref:17
is a block of words describing the last message read on the $RECEIVE file. It has
the following structure:
[0] I/O type. Indicates the data operation last performed by the message sender.
Values are:
0 Not a data message (system message)
1 Sender called WRITE
2 Sender called READ
3 Sender called WRITEREAD
[ 1 ] Maximum reply count. The maximum number of bytes of data that can be
returned b\y REPLY. (as determined by the read count of the sender).
[ 2 ] Message tag. The value that identifies the request message just read. To
associate a reply with a request, the message tag is passed to the REPLY
procedure. The value returned here is an integer between zero and
receive depth - 1, inclusive, that had not been in use as a message
tag. When a reply is made, its associated message tag value is made
available for use as a message tag for a subsequent request message.
[3] File number. The value that identifies the file associated with this message
in the requesting process. If the received message is a system message
that is not associated with a specific file open, this field contains -1.
[4:5] Sync ID. The sync ID associated with this message. If the received
message is a system message, this field is valid only if the message is
associated with a specific file open; otherwise this field is not applicable
and should be ignored. See “Considerations.”
[6:15]
Sender process handle. The process handle of the process that sent the
last message. For system messages other than the open, close,
CONTROL, SETMODE, SETPARAM, RESETSYNC, or CONTROLBUF
messages, the null process handle (-1 in each word) is returned.
[16] Open label. The value assigned by the application (when replying to the
open system message) to the open on which the received message was
sent. It is often used to find the open table entry for the message. If this
value is unavailable, -1 is returned.