我在单独的线程应用程序配置文件中进行监视,在某些情况下,该文件可能是另一个XML或另一个XML中的INI。线程监控目录的代码(在 Delphi 中)是这样的:
procedure TWatcherThread.Execute;
type
PFileNotifyInformation = ^TFileNotifyInformation;
TFileNotifyInformation = record
NextEntryOffset: DWORD;
Action: DWORD;
FileNameLength: DWORD;
FileName: WideChar;
end;
const
BufferLength = 65536;
var
Filter, BytesRead: DWORD;
InfoPointer: PFileNotifyInformation;
Offset, NextOffset: DWORD;
Buffer: array[0..BufferLength - 1] of byte;
Overlap: TOverlapped;
Events: array[0..1] of THandle;
WaitResult: DWORD;
FileName, s: string;
begin
if fDirHandle <> INVALID_HANDLE_VALUE then begin
Filter := FILE_NOTIFY_CHANGE_LAST_WRITE;
FillChar(Overlap, SizeOf(TOverlapped), 0);
Overlap.hEvent := fChangeHandle;
Events[0] := fChangeHandle;
Events[1] := fShutdownHandle;
while not Terminated do begin
FillChar(Buffer,SizeOf(Buffer),0);
if ReadDirectoryChangesW (fDirHandle, @Buffer[0], BufferLength, TRUE,
Filter, @BytesRead, @Overlap, nil)
then begin
WaitResult := WaitForMultipleObjects(2, @Events[0], FALSE, INFINITE);
if WaitResult = WAIT_OBJECT_0 then begin
InfoPointer := @Buffer[0];
Offset := 0;
repeat
NextOffset := InfoPointer.NextEntryOffset;
FileName := WideCharToString(@InfoPointer.FileName);
if (InfoPointer.Action = FILE_ACTION_MODIFIED) and (CompareText(FileName, 'MyConfig.ini') = 0) then begin //read changes in config or INI file
// Do Action.. refresh runtime flags
end;
PByte(InfoPointer) := PByte(DWORD(InfoPointer) + NextOffset);
Offset := Offset + NextOffset;
until NextOffset = 0;
end;
end;
end;
end;
end;
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为什么它的信号至少2次,如何得到正确的信号时,一些标志在配置文件被更改,并保存?
1条答案
按热度按时间cygmwpex1#
Raymond Chen在他的博客上解释道:https://devblogs.microsoft.com/oldnewthing/20140507-00/?p=1053
简而言之,“因为多个东西被修改了。”