Beefy Boxes and Bandwidth Generously Provided by pair Networks
Clear questions and runnable code
get the best and fastest answer

Re: file locking problem!

by Anonymous Monk
on Jun 29, 2001 at 21:53 UTC ( #92737=note: print w/replies, xml ) Need Help??

in reply to file locking problem!

This is a race condition. There is no reason to believe that because a file did not exist when the previous instruction was executed that it still does not exist (your operating system could have run another proccess in between). So when your while (-e $LockFile && time < $EndTime) loop ends there is no guarantee that the file does not exist (infact, even if there were no race condition, you have a time limit on this loop but never check to see if the loop terminated because time was up or if it terminated because the file doesn't exist -- but like I said, checking to see if the file doesn't exist would still be a bug). If you are unable to use flock(), you could see if you're able to use sysopen with the O_EXCL flag which will guarantee that the file does not exist when opened (if it does exist, the sysopen call will fail and you'll probably want to handle this rather than simply returning from the function)

Log In?

What's my password?
Create A New User
Domain Nodelet?
Node Status?
node history
Node Type: note [id://92737]
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others surveying the Monastery: (5)
As of 2023-06-08 01:53 GMT
Find Nodes?
    Voting Booth?
    How often do you go to conferences?

    Results (29 votes). Check out past polls.