Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (F)
Guardian Procedure Calls Reference Manual—522629-013
5-64
FILE_GETINFOBYNAME_ Procedure
<0:14> Reserved and undefined.
<15> File is an OSS file.
Considerations
•
Specifying a subtype 30 process
When FILE_GETINFOBYNAME_ is called with a file name that designates a
subtype 30 process, the procedure sends a device type inquiry system message to
the process to determine the device type and subtype (unless disabled by
options.<15>). The message sent by FILE_GETINFOBYNAME_ is either in D-
series-format (message -106) or C-series-format (message -40) depending on the
options used when the subtype 30 process opened $RECEIVE. The formats of
these completion messages are described in the
Guardian Procedure Errors and
Messages Manual.
The subtype 30 process replies with the requested information in system message
-106 or -40, corresponding to the message used in the inquiry. The returned
device type value should be one of those listed in Appendix A, Device Types and
Subtypes. If the message response is incorrectly formatted, the
FILE_GETINFOBYNAME_ caller receives device type and subtype values of 0.
The REPLY caller (the subtype 30 process) receives an error 2.
A deadlock occurs if a subtype 30 process calls FILE_GETINFOBYNAME_ on its
own process name.
•
Using the nowait option
If you call FILE_INFOBYNAME_ procedure in a nowait manner, the results are
returned in the nowait FILE_GETINFOBYNAME_ completion message (-108), not
in the output parameters of the procedure. The format of this completion message
is described in the
Guardian Procedure Errors and Messages Manual. If error is
not 0, no completion message is sent to $RECEIVE. Errors can be reported either
on return from the procedure, in which case
error might be meaningful, or
through the completion message sent to $RECEIVE.
The system reports a path error only after automatically making retries.
When the nowait option is used, any step of the inquiry operation might be
asynchronous to the caller. However, only simulation inquiries to subtype 30
processes are guaranteed to be asynchronous.
When a process pair uses the nowait option, the nowait FILE_GETINFOBYNAME_
completion message is sent only to the process that made the call, not to the other
member of the pair.
Switching ownership from the primary to the backup process can leave outstanding
inquiries. The CHECKSWITCH procedure automatically discards these as it
becomes the backup process.