Quote Originally Posted by wysota View Post
It's called mandatory locking. AFAIK Windows uses it by default. It's not advised though. You can also use advisory locks. For example see "man 2 flock" or simmilar.
Hi wysota,
Thanks for your reply.

I am working on an application where I can open multiple instances of same aplication (Qt). Presently the user is able to open the same file in any instances. The files are in text format. Can you provide me with some resources or something that can help me.

The solution should be portable.
Waiting eagerly