Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (O)
Guardian Procedure Calls Reference Manual—522629-013
11-23
OPEN Procedure (Superseded by FILE_OPEN_
Procedure )
The file system does not enforce read-only or write-only access for unlabeled tape,
even though no error is returned if you specify one of these access modes when
opening a tape file.
•
File open—exclusion and access mode checking
When a file open is attempted, the requested access and exclusion modes are
compared with those of any opens already granted for the file. If the attempted
open is in conflict with other opens, the open fails with error 12.