01-22-2003
Quote:
Originally posted by champion
this seems to be a good idea. but when will the lock file be deleted? what if user just does not logout but plug out the electric power cable?
Naturally, you would have to clear the lock files when the system reboots after a crash. This is true for all programs that use lockfiles. You simply write a startup script that looks for and clears lock files when the system reboots.
As for logout actions, this is possible also. One possibility is to use the
trap facility in the shell.
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lock(9s) lock(9s)
NAME
lock - General: Contains complex lock-specific information
SYNOPSIS
The lock data structure is an opaque data structure; that is, its associated members are referenced and manipulated by the operating system
and not by the user of the complex lock mechanism. Therefore, this reference page omits a description of the lock data structure's associ-
ated members.
DESCRIPTION
The lock data structure is the complex lock structure that contains complex lock-specific information. A kernel module writer using the
complex lock method declares a pointer to a lock data structure and passes its address to the associated lock routines.
NOTES
The header file <lock.h> shows typedef statements that assign the alternate name lock_data_t for the complex lock structure and lock_t for
a pointer to the complex lock structure.
FILES
SEE ALSO
Routines: lock_done(9r), lock_init(9r), lock_read(9r), lock_terminate(9r), lock_try_read(9r), lock_try_write(9r), lock_write(9r)
Data Structures: slock(9s)
lock(9s)