Guardian Procedure Calls Reference Manual

• Remote opener with a long process file name
If the calling process used FILE_OPEN_ to open $RECEIVE and did not request to receive
C-series format messages, and if the last message read from $RECEIVE is from a remote
process that has a process name consisting of more than five characters, then the value of
process-id returned by RECEIVEINFO is undefined.
• Sync ID definition
A sync ID is a double-word, unsigned integer. Each process file that is open has its own sync
ID. Sync IDs are not part of the message data; rather, the sync ID value associated with a
particular message is obtained by the receiver of a message by calling the RECEIVEINFO
procedure. A file's sync ID is set to zero at file open and when the RESETSYNC procedure is
called for that file (RESETSYNC can be called directly or indirectly through the
CHECKMONITOR procedure). For information about checkpointing, see the Guardian
Programmer's Guide.
When a request is sent to a process (that is, CONTROL, CONTROLBUF, close, open,
SETMODE, WRITE, or WRITEREAD to a process file), the requestor's sync ID is incremented
by 1 just before to the request is sent. (Therefore, a process' first sync ID subsequent to an
open has a value of 0.)
• Duplicate requests
The sync-id parameter allows the server process (that is, the process reading $RECEIVE) to
detect duplicate requests from requester processes. Such duplicate requests are caused by a
backup requester process reexecuting the latest request of a failed primary requester process.
NOTE: Neither a CANCELREQ or AWAITIO timeout completion have any affect on the sync
ID (that is, it will be an ever-increasing value).
Also, the sync ID is independent of the sync-depth parameter to OPEN.
• Server process identifying separate opens by the same requester
The filenum parameter allows the server process to identify separate opens by the same
requester process. The value returned in filenum is the same as the file number used by the
requester to make this request.
Example
CALL RECEIVEINFO (PROCID , , , REQ^FNUM , REQ^READCOUNT);
Related Programming Manual
For programming information about the RECEIVEINFO procedure, see the Guardian Programmer's
Guide.
RECEIVEINFO Procedure (Superseded by FILE_GETRECEIVEINFO[L]_ Procedures) 1229