"listening" to file changes in C / C ++ (on Windows)

Question

Is there any way I can target a specific file and get all the changes that are made to it?

For example, the file Names.txt. Can I see the file for names added? and then write them to the console?

Sample code without compilation in Dev-C ++ 4.9.9.2

#include <windows.h> #include <stdlib.h> #include <stdio.h> #include <tchar.h> void RefreshDirectory(LPTSTR); void RefreshTree(LPTSTR); void WatchDirectory(LPTSTR); int _tmain(int argc, TCHAR *argv[]) { if(argc != 2) { _tprintf(TEXT("Usage: %s <dir>\n"), argv[0]); return 1; } WatchDirectory(argv[1]); } void WatchDirectory(LPTSTR lpDir) { DWORD dwWaitStatus; HANDLE dwChangeHandles[2]; TCHAR lpDrive[4]; TCHAR lpFile[_MAX_FNAME]; TCHAR lpExt[_MAX_EXT]; _tsplitpath_s(lpDir, lpDrive, 4, NULL, 0, lpFile, _MAX_FNAME, lpExt, _MAX_EXT); lpDrive[2] = (TCHAR)'\\'; lpDrive[3] = (TCHAR)'\0'; // Watch the directory for file creation and deletion. dwChangeHandles[0] = FindFirstChangeNotification( lpDir, // directory to watch FALSE, // do not watch subtree FILE_NOTIFY_CHANGE_FILE_NAME); // watch file name changes if (dwChangeHandles[0] == INVALID_HANDLE_VALUE) { printf("\n ERROR: FindFirstChangeNotification function failed.\n"); ExitProcess(GetLastError()); } // Watch the subtree for directory creation and deletion. dwChangeHandles[1] = FindFirstChangeNotification( lpDrive, // directory to watch TRUE, // watch the subtree FILE_NOTIFY_CHANGE_DIR_NAME); // watch dir name changes if (dwChangeHandles[1] == INVALID_HANDLE_VALUE) { printf("\n ERROR: FindFirstChangeNotification function failed.\n"); ExitProcess(GetLastError()); } // Make a final validation check on our handles. if ((dwChangeHandles[0] == NULL) || (dwChangeHandles[1] == NULL)) { printf("\n ERROR: Unexpected NULL from FindFirstChangeNotification.\n"); ExitProcess(GetLastError()); } // Change notification is set. Now wait on both notification // handles and refresh accordingly. while (TRUE) { // Wait for notification. printf("\nWaiting for notification...\n"); dwWaitStatus = WaitForMultipleObjects(2, dwChangeHandles, FALSE, INFINITE); switch (dwWaitStatus) { case WAIT_OBJECT_0: // A file was created, renamed, or deleted in the directory. // Refresh this directory and restart the notification. RefreshDirectory(lpDir); if ( FindNextChangeNotification(dwChangeHandles[0]) == FALSE ) { printf("\n ERROR: FindNextChangeNotification function failed.\n"); ExitProcess(GetLastError()); } break; case WAIT_OBJECT_0 + 1: // A directory was created, renamed, or deleted. // Refresh the tree and restart the notification. RefreshTree(lpDrive); if (FindNextChangeNotification(dwChangeHandles[1]) == FALSE ) { printf("\n ERROR: FindNextChangeNotification function failed.\n"); ExitProcess(GetLastError()); } break; case WAIT_TIMEOUT: // A timeout occurred, this would happen if some value other // than INFINITE is used in the Wait call and no changes occur. // In a single-threaded environment you might not want an // INFINITE wait. printf("\nNo changes in the timeout period.\n"); break; default: printf("\n ERROR: Unhandled dwWaitStatus.\n"); ExitProcess(GetLastError()); break; } } } void RefreshDirectory(LPTSTR lpDir) { // This is where you might place code to refresh your // directory listing, but not the subtree because it // would not be necessary. _tprintf(TEXT("Directory (%s) changed.\n"), lpDir); } void RefreshTree(LPTSTR lpDrive) { // This is where you might place code to refresh your // directory listing, including the subtree. _tprintf(TEXT("Directory tree (%s) changed.\n"), lpDrive); } 

Answer 1

That's right. See FindFirstChangeNotification , ReadDirectoryChangesW , Example .

Answer 2

See MSDN - you will need to look at the directory and ignore changes to other files that you do not like about.