Back up of modified files

[erankushmehta]

Hi all,
There are certain files (like doc, txt etc.) in a directory. I want to make an application which creates a back up of the files as soon as it has been closed after modification.
How can i approach that? Kindly Guide.

[ovidiucucu]

Call CopyFile to copy the original file in a new one before saving the modifications.

[philkr]

This function will help to be notified of modification: FindFirstChangeNotification()

[erankushmehta]

This function will help to be notified of modification: FindFirstChangeNotification()

dwChangeHandles[0] = FindFirstChangeNotification  ( 
"C:\\Test",                   // directory to watch 
TRUE,                         // watch subtree 

FILE_NOTIFY_CHANGE_ATTRIBUTES); // watch file attribute changes

This notifies if any attributes are changed.I just want to know the files which aremodified & create their back up as soon as they are modified.
Please Help

[John E]

ReadDirectoryChangesW() can notify you of all sorts of directory changes - for example, changed attributes, files added, files deleted, files modified, files renamed etc. However, it only works with Windows XP and 2000 as far as I'm aware.

[Gunaamirthavelu]

what exactly u want ? can u explain?

[erankushmehta]

what exactly u want ? can u explain?

I want to be notified as soon as any file in a given directory is modified & then create its back up instantaneously.

[PadexArt]

FILE_NOTIFY_CHANGE_ATTRIBUTES); // watch file attribute changes [/CODE]

This notifies if any attributes are changed.I just want to know the files which aremodified & create their back up as soon as they are modified.
Please Help

FILE_NOTIFY_CHANGE_ATTRIBUTES is not the only flag you can pass to the function. FILE_NOTIFY_CHANGE_LAST_WRITE is what you need.

If your target platforms match its requirements you should check the ReadDirectoryChangesW function as well. This is a function to be used in conjunction with FindFirstChangeNotification. With it you can pinpoint the changes occuring in a directory.

You can find a sample of its usage here: MSDN - fwatch

Another example is CodeProject - Directory Change Watcher

[erankushmehta]

FILE_NOTIFY_CHANGE_ATTRIBUTES is not the only flag you can pass to the function. FILE_NOTIFY_CHANGE_LAST_WRITE is what you need.

Thanks, i get the notification.Now how to get the filename which was modified so that its back up may be created..

[PadexArt]

Thanks, i get the notification.Now how to get the filename which was modified so that its back up may be created..

This information has been provided already. Read the posts to their full extent and follow the links.

[erankushmehta]

ReadDirectoryChanges & FILE_NOTIFY_INFORMATION will do. But i am not able to comprehend the complex parameters & getting the relevant info from the file notify structure.

[John E]

Follow PadexArt's link to the directory change watcher. Everything is wrapped up with ready-made handlers for OnFileAdded(0, OnFileRemoved(), OnFileModified(), and OnFileNameChanged(). They don't come much easier than that.

[erankushmehta]

if(!ReadDirectoryChangesW( pdi->m_hDir,
                                             pdi->m_Buffer,//<--FILE_NOTIFY_INFORMATION records are put into this buffer
		             READ_DIR_CHANGE_BUFFER_SIZE,
		             pdi->m_bWatchSubDir,
		             pdi->m_dwChangeFilter,
		             &pdi->m_dwBufLength,//this var not set when using asynchronous mechanisms...
		             &pdi->m_Overlapped,
		             NULL))

i am getting following error:

error C2065: 'ReadDirectoryChangesW' : undeclared identifier

I am using Windows 2000 Professional.

[John E]

Try putting the following line in one of your header files (preferably stdafx.h )

#define _WIN32_WINNT 0x400

[erankushmehta]

Try putting the following line in one of your header files (preferably stdafx.h )

#define _WIN32_WINNT 0x400

tried..but to no avail...

Plz help.