Guardian Procedure Calls Reference Manual
filenum
output
INT:ref:1
returns the file number of the file in the requesting process associated with this message. If the
received message is a system message that is not associated with a specific file open, this
parameter contains -1.
read-count
output
INT:ref:1
returns the number of bytes requested in reply to the message. If the message is the result of a
request made in a call to WRITE[X], read-count will be 0. If the message is the result of a
request made in a call to WRITEREAD[X], read-count is the same as the read count value
passed by the requester to WRITEREAD[X].
iotype
output
INT:ref:1
returns a value indicating the data operation last performed by the message sender:
Not a data message (system message).0
Sender called WRITE.1
Sender called READ.2
Sender called WRITEREAD.3
Condition Code Settings
indicates that $RECEIVE is not open.< (CCL)
indicates that RECEIVEINFO is successful.= (CCE)
does not return from RECEIVEINFO.> (CCG)
Considerations
• Process ID and RECEIVEINFO
The four-word process ID returned by RECEIVEINFO following receipt of a process open,
close, CONTROL, SETMODE, SETPARAM, RESETSYNC, or CONTROLBUF system message,
or a data message, identifies the process associated with the operation.
• When the high-order three words of process ID are zero
The high-order three words of the process ID are zero following the receipt of system messages
other than process open, close, CONTROL, SETMODE, RESETSYNC, and CONTROLBUF.
• Synthetic process ID
If HIGHREQUESTERS is enabled for the calling process (either because the ?HIGHREQUESTERS
flag is set in the program file or because the caller used FILE_OPEN_ to open $RECEIVE) and
the last message was sent by a high-PIN process, then the returned process ID is as described
above except that the value of the PIN is 255. This form of the process ID is referred to as a
synthetic process ID. It is not a full identification of the process but it is normally sufficient for
distinguishing, for example, one requester from another requester. For further details, see the
Guardian Programmer's Guide.
1228 Guardian Procedure Calls (R)