USB读写时，能通过CreateFile获取句柄，调用WriteFile或者ReadFile时总是返回失败，错误码是997，下面是写入HID的代码
   if(m_hUsb==INVALID_HANDLE_VALUE)return;

unsigned char OutputBuffer[70];
DWORD nWriteBytes;
HANDLE WriteEvent = CreateEvent(NULL, true, false, NULL);
OVERLAPPED writeOverlap;
writeOverlap.hEvent = WriteEvent;
writeOverlap.Offset        = 0;
writeOverlap.OffsetHigh = 0;

UpdateData(TRUE);
OutputBuffer[0] = 0x00;
OutputBuffer[1] = 0x01;
OutputBuffer[2] = 0x02;
OutputBuffer[3] = 0x03;
//         for(int i=1; i-1<m_SendStr.GetLength();i++)
//         {
//          OutputBuffer = m_SendStr.GetAt(i-1);
//          //WideCharToMultiByte
//         }
ResetEvent(WriteEvent);
DWORD len = m_SendStr.GetLength() + 1;
if (WriteFile(m_hUsb, &OutputBuffer, 65, &nWriteBytes, &writeOverlap))
{
AfxMessageBox(_T("Succ write"));
}else
{
DWORD Err = GetLastError();
cout<<Err;
}

  求指点，谢谢

最全USB HID开发资料，悉心整理一个月，亲自测试
https://www.stmcu.org.cn/module/ ... &fromuid=366506
(出处: 意法半导体STM32/STM8技术社区)


供参考

//
// MessageId: ERROR_IO_PENDING
//
// MessageText:
//
//  Overlapped I/O operation is in progress.
//
#define ERROR_IO_PENDING                 997L    // dderror

WriteFile返回了 但WriteFile操作没有完成 而已
自己处理下这个错误码.

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