Well done that man!
"Rasmus Lerdorf" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I think you guys are making this way more complicated than it needs to be. > Anytime you start talking about locking files, you need to apply a huge > reality check to yourself and sit down and approach the problem from a > different direction. > > In this case could I suggest that you make use of the fact that appends of > less than a blocksize are atomic. Therefore, why not simply append a > single character to a text file for each vote? If you are voting for a > list of things, assigning a character to each item and simply append 'a', > 'b', 'c' or 'd' to your file. The size of the file instantly gives you > the number of votes cast. Reading the file and counting the number of > times each letter occurs using something like substr_count() will give you > the number of votes for each option. > > That gives you a lockless and flexible system without the risk of deadlock > or missing votes due to race conditions. > > -Rasmus > > On Wed, 22 May 2002, 1LT John W. Holmes wrote: > > > > A good structure would be to have one file for each possible answer and > > each > > > file contains the number of votes it has recieved. > > > Then: > > > --> Open file for the chosen option as read only > > > --> Read the value in the file > > > --> Close the file > > > --> Increase the value by one using ++ > > > --> Open the file again in write mode > > > --> Lock the file > > > --> Write the new value to the file - old one overwritten > > > --> Unlock the file > > > --> Close the file > > > > > > That's a bad method. You have to have the lock around the read and the > > write. With your method, 5 users might read the file, all getting 99 for the > > count, and then each one will try to seperatly write 100 to the file. So you > > lose 4 actual counts. You want to open the file, read it, update value, > > write it, unlock, and close the file. > > > > Using multiple files would just be a waste of space in my opinion. A locked > > file doesn't stop the script, it simply waits for the file to be unlocked > > and then continues on. > > > > ---John Holmes... > > > > > > -- > > PHP General Mailing List (http://www.php.net/) > > To unsubscribe, visit: http://www.php.net/unsub.php > > > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
