Winapi 异步ReadDirectoryChangesW失败，错误为\u参数无效

我已经设法同步使用了

ReadDirectoryChangesW

，但是当我尝试使用完成端口时，

ReadDirectoryChangesW

总是返回

错误\u无效\u参数

。我想我的代码中应该有一些明显的错误，但我无法理解

我的代码是基于

---

正如Hans Passant善意地提醒的那样，他已经说过，如果目录与完成端口关联，则不能使用完成例程。在本例中，我通过等待完成端口解决了问题，即，

ReadDirectoryChangesW（…，&overlapped，0）

完整的代码如下

while (true) {
    OVERLAPPED overlapped;
    memset(&overlapped,0,sizeof(overlapped));
    BOOL success = ReadDirectoryChangesW(h,
            &buffer[0],
            4096*sizeof(DWORD),
            FALSE, notifyFilter, 0, &overlapped,0);

    if (!success) {
      if (GetLastError()==ERROR_INVALID_HANDLE) {
        //asynchronously closed by cancel
        CloseHandle(p); //close completion port
        return 0;
      } else {
        CloseHandle(h); //close directory handle
        CloseHandle(p); //close completion port
        return 1;
      }
    }

    DWORD di;
    LPOVERLAPPED lpOverlapped;
    if (!GetQueuedCompletionStatus(p,&bytesReturned,&di,&lpOverlapped,1000)) {
        int ret;
        if (GetLastError()==WAIT_TIMEOUT) {
            if (GetFileAttributes(directory)!=INVALID_FILE_ATTRIBUTES) {
                continue; //timeout
            } else {
                //directory has been deleted or renamed
                ret=0;
            }
        } else {
            //other failure
            ret=1;
        }
        CloseHandle(h); //close directory handle
        CloseHandle(p); //close completion port
        return ret;
    }

    char* ptr = (char*)&buffer[0];
    char* end = ptr+bytesReturned;
    while (ptr<end) {
      FILE_NOTIFY_INFORMATION *info = (FILE_NOTIFY_INFORMATION*) ptr;
      //process FILE_NOTIFY_INFORMATION
      ptr+=info->NextEntryOffset;
      if (!info->NextEntryOffset) break;
    }
  }

while（true）{
重叠；
memset（&overlapped，0，sizeof（overlapped））；
BOOL success=ReadDirectoryChangesW（h，
&缓冲区[0]，
4096*sizeof（德沃德），
FALSE，notifyFilter，0，重叠（&O），0）；
如果（！成功）{
if（GetLastError（）==错误\u无效\u句柄）{
//通过取消异步关闭
CloseHandle（p）；//关闭完成端口
返回0；
}否则{
CloseHandle（h）；//关闭目录句柄
CloseHandle（p）；//关闭完成端口
返回1；
}
}
德沃德·迪；
lp重叠lp重叠；
如果（！GetQueuedCompletionStatus（p，&bytesReturned，&di，&lpOverlapped，1000））{
int ret；
如果（GetLastError（）==等待\u超时）{
如果（GetFileAttributes（目录）！=无效的文件属性）{
继续；//超时
}否则{
//目录已被删除或重命名
ret=0；
}
}否则{
//其他故障
ret=1；
}
CloseHandle（h）；//关闭目录句柄
CloseHandle（p）；//关闭完成端口
返回ret；
}
char*ptr=（char*）和缓冲区[0]；
char*end=ptr+bytes返回；
while（ptrNextEntryOffset；
如果（！info->nexteryOffset）中断；
}
}
您没有显示notifyFilter和myFileIOCompletionRoutine定义。CreateIoCompletionPort返回NULL如果失败，则测试不正确。可能CreateIoCompletionPort失败？@AlexFarber，谢谢您指出，但CreateIoCompletionPort返回有效句柄。@AlexFarber我添加了notifyFilter.myFileIOCompletionRout的声明ine目前什么都不做，即MSDN库文章中的重要说明：
要通过完成例程接收通知，请**不要**将目录与完成端口关联。
如果您帮助很大，请删除CreateIoCompletionPort（）调用。
while (true) {
    OVERLAPPED overlapped;
    memset(&overlapped,0,sizeof(overlapped));
    BOOL success = ReadDirectoryChangesW(h,
            &buffer[0],
            4096*sizeof(DWORD),
            FALSE, notifyFilter, 0, &overlapped,0);

    if (!success) {
      if (GetLastError()==ERROR_INVALID_HANDLE) {
        //asynchronously closed by cancel
        CloseHandle(p); //close completion port
        return 0;
      } else {
        CloseHandle(h); //close directory handle
        CloseHandle(p); //close completion port
        return 1;
      }
    }

    DWORD di;
    LPOVERLAPPED lpOverlapped;
    if (!GetQueuedCompletionStatus(p,&bytesReturned,&di,&lpOverlapped,1000)) {
        int ret;
        if (GetLastError()==WAIT_TIMEOUT) {
            if (GetFileAttributes(directory)!=INVALID_FILE_ATTRIBUTES) {
                continue; //timeout
            } else {
                //directory has been deleted or renamed
                ret=0;
            }
        } else {
            //other failure
            ret=1;
        }
        CloseHandle(h); //close directory handle
        CloseHandle(p); //close completion port
        return ret;
    }

    char* ptr = (char*)&buffer[0];
    char* end = ptr+bytesReturned;
    while (ptr<end) {
      FILE_NOTIFY_INFORMATION *info = (FILE_NOTIFY_INFORMATION*) ptr;
      //process FILE_NOTIFY_INFORMATION
      ptr+=info->NextEntryOffset;
      if (!info->NextEntryOffset) break;
    }
  }