判断文件是否在使用

function IsFileInUse(fName:string):Boolean;

var

    HFileRes:HFile;

begin

    Result :=False;

    if not FileExists(fname) then

      exit;

    HFileRes :=CreateFile(pchar(fName),GENERIC_READ or GENERIC_WRITE,0,nil,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);

    Result :=(HFileRes=INVALID_HANDLE_VALUE);

    if not Result then

        CloseHandle(HFileRes);

end;