Question

Is there a way ( or an API ) to know when a text file is edited ( by a program or by a person ) and do a specific action ?

For example: I want to show a MessageBox when the file c:\Users\john\free.txt is edited.

Answer 1

Depends on when you exactly want to know it.

• is your application running continuously and do you want to see any change as soon as possible?
• is your application a simple command-line application that needs to check for changes once?

In the second case, you could check the modification dates of the file (as suggested by PoweRoy and Michal) or use a hash (as suggested by PoweRoy).

If your application is running continuously, you should use the FindFirstChangeNotification and ReadDirectoryChanges functions. You can read more about it on the following pages:

• http://msdn.microsoft.com/en-us/library/windows/desktop/aa364417(v=vs.85).aspx
• http://msdn.microsoft.com/en-us/library/windows/desktop/aa365465(v=vs.85).aspx.