Record locking and future releases of the UNIX system
Provisions have been made for file and record locking
in a UNIX system environment.
In such an environment the system on which the locking process
resides may be remote from the system
on which the file and record locks reside.
In this way multiple processes on different systems may put locks
upon a single file that resides on one of these or yet another system.
The record locks for a file reside on the system that maintains the file.
It is also important to note that deadlock detection/avoidance is
only determined by the record locks being held by and for a single system.
Therefore, it is necessary that a process only hold record
locks on a single system at any given time for the deadlock mechanism
to be effective.
If a process needs to maintain locks over several systems, it is suggested
that the process avoid the sleep-when-blocked
features of fcntl or lockf and that
the process maintain its own deadlock detection.
If the process uses the sleep-when-blocked feature, then
a timeout mechanism should be provided by the process so that
it does not hang waiting for a lock to be cleared.
Basic STREAMS operations
Advisory versus mandatory locking
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 27 April 2004