user's system mailbox
is useful for a client mail program to
attain proper locking. lockspool
for the calling user and retains it
until stdin is closed or a signal like
is received. Additionally, the
superuser may specify the name of a user in order to lock a different mailbox.
is able to create the lock file,
“1” is written to stdout, otherwise “0” is written and
an error message is written to stderr. lockspool
will try up to 10 times to get the lock (sleeping for a short period in
Typical usage is for a user mail agent (such as
) to open a pipe to
when it needs to lock the user's mail
spool. Closing the pipe will cause lockspool
release the lock.
- user's mail lock file
utility exits 0 on success, and 1 if
an error occurs.
program appeared in