how to restrict to run only one instance of application at one time in mfc -

I am working on a new project. In this new project, I have to run the application once only once. Two examples of applications should not be run if the user has attempted to open another instance, then he should give an error.

Can someone help me? How can I get this?

Thanks

I found this link to be basically for the same issue of CreateMutex Is about using.

According to this link, you can find that your app is currently running, you can use "CreateMutex". When your application tries to run another application, it will get an error. There are some sample codes for this, hope it will help you.