Handle two programs writing to the same file in C++? Help?
Hi, how to synchronize two cgi programs called
from browser, and write data to the same file
at the same time in C++?
Thank you very much,
WHY??? And how are you at Shared Memory?
Hi, here's the more info:
It's a cgi prgram which read a file, and change some data in it, then write to the same file.
There's a possibility that two users access the
same cgi program at the same time, then write to
the same file at the same time, that caused
Is there's a way to handle it in C++?
Last edited by natxie; 09-20-2001 at 06:05 PM.
concurrency is your problem. you have more than one 'user' trying to write to the same file at the same time, not good.
Now is your question about CGI or C++?
Either way, minimize your file IO. Only write to file when absolutely necessary, then open, write, close as fast as possible.
Why are you using file? Sounds like you need a DB.
I'm pretty sure c++ lets you lock your file as well, lock -> write/read -> unlock, but you might have already tried that. Not sure if it would do much or not, but I believe thats what the intention of the lock is! (mebbe, mebbe not!)
...you can look into semaphors if you want also!!
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