On Fri, 8 Aug 2003 02:32:05 +0500, Sara wrote:
> open(NUMBER,">>data.txt");
> flock (NUMBER, 2);
> close (NUMBER);
> closing a file automatically removes the lock??
The answer is yes. When you close files they will automatically
un-locked.
One thing though, you might want to use the fcntl module which imports
the following flock constants:
# Importing flock constants:
# (LOCK_SH, LOCK_EX, LOCK_NB and LOCK_UN)
use fcntl ':flock';
> My second question is how I can delay the execution of a script (If
> two users trying to execute the same script) for 30 sec by using
> sleep function? and If I implement sleep function in my script .....
> Do I really need to use 'flock' in my script or there is no need then.
It depends in which environment you want to run your script. If it only
needs to run in the *nix world you might want your script to:
(a) check for a file (-e)
(b) if file doesn't exist, create it and write the scripts PID
(getpid() or $$ or $PID or $PROCESS_ID) into it
(c) if the file is found read the PID and ping the PID for existance
(sending a signal with kill()) [*]
(d) if PID exists you will wait 30 seconds (sleep()) and go back to
(c) or wait for the other script to finish (waitpid()).
(e) once your script gets the ok from (a) or (d) you can goto (b).
If you are interested in another solution which will die () if the same
script is already running, just ping me by email.
thanks
/oliver
[*] You might want to install a signal handler in your script that will
ignore the send signal though. E.g.:
local $SIG{INT} = 'IGNORE';
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