readdirectorychangesw

I’m using ReadDirectoryChangesW to spy a folder, if I’m copying a large file to the folder, I can receive multiple FILE_ACTION_MODIFIED messages, it seems each time windows writes a large chunk of the file, you get the file modified notification for each time. I tried to use CreateFile API to check if the file can open by AP or not, but sometime, some of files are always locked by other AP, for example, if you are opening the Outlook, the PST will update, but my AP can’t access it, we have to start Shadow Copy to open it. So my question is, how to know a file is finished copying? This is a

Exactly as it sounds, I'm attempting asynchronous ReadDirectoryChangesW with IO Completion and it isn't working, specifically, GetLastError repeatedly returns 258 ( GetQueuedCompletionStatus timeout). I have structs: typedef struct dirinfo_struct { HANDLE hDirFH; // directory handle OVERLAPPED Overlapped; // overlapped storage int len_buffer; // buffer length wchar_t* buffer; // buffer itself wchar_t* directory_name; // target name } dirinfo_t; typedef struct dirmon_struct { HANDLE hDirOPPort; // handle to the IO port. dirinfo_t* dirinfo; // pointer to the struct above. } dirmon_t; for storing

There are many posts on the internet about the ReadDirectoryChangesW API function missing files when there is a lot of file activity. Most blame the speed at which the ReadDirectoryChangesW function loop is called. This is an incorrect assumption. The best explanation I have seen is in the following post, the comment on Monday, April 14, 2008 2:15:27 PM http://social.msdn.microsoft.com/forums/en-US/netfxbcl/thread/4465cafb-f4ed-434f-89d8-c85ced6ffaa8/ The summary is that the ReadDirectoryChangesW function reports file changes as they leave the file-write-behind queue, not as they are added.

I use ReadDirectoryChangesW to watch a specified directory and update indexing structures whenever a change is detected. I use the following code (roughly) var InfoPointer : PFileNotifyInformation; NextOffset : DWORD; ... while (not Terminated) do begin if ReadDirectoryChangesW (FDirHandle, FBuffer, FBufferLength, True, FFilter, @BytesRead, @FOverlap, nil) then begin WaitResult := WaitForMultipleObjects (2, @FEventArray, False, INFINITE); if (WaitResult = waitFileChange) then begin InfoPointer := FBuffer; repeat NextOffset := InfoPointer.NextEntryOffset; ... PByte (InfoPointer) := PByte