Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (F)
Guardian Procedure Calls Reference Manual—522629-013
5-123
FILE_OPEN_ Procedure
•
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. Table 5-7
lists the
possible current modes and requested modes, indicating whether an open
succeeds or fails.
For the Optical Storage Facility only, the “process exclusive” exclusion mode is
also supported. Process exclusive is the same as exclusive for opens by other
processes, but the same as shared for opens by the same process.
Note. Protected exclusion mode has meaning only for disk files. For other files, specifying
protected exclusion mode is equivalent to specifying shared exclusion mode.