hi,
i m trying to make singleton application so only one instace can run at a time. i tried to used executable name and process id but any one can change executable name.
i dont want to use any port because if that port is used by any other application then application will not run.
Do u have any idea how i can make my application as single application (c++) ?

Manish

If you store process ID in a file in some directory and have the process run other then a regular user then you should be able to make a application only run once. The directory will be owned by the process user with r/w permissions only will read permissions for everyone else. This would be good for a process that is started at boot.

Another idea not as complex and similar to the first would be to have the directory that stores the process ID file be hidden somewhere obscure. The process looks for the file at boot and if it exists quit with a already running message. A gracefull shutdown would delete the file. If the program crashes then you would have a problem.