win32 readfile异步操作串口问题

我写了一个程序，需要循环接收串口数据。使用readfile时函数总是在接收到0个字节的时候返回。这是什么原因？而且必须使用sleep。否则总是接收不到正常的数据。请各位高手解决下。如何让readfile异步阻塞，或者硬性规定一定要接受多少个字节？

while (TRUE)
	{
		DWORD dwError;
		DWORD dwWantRead = 16;
		DWORD dwRealRead = 0;
		unsigned char pReadBuf[16] = {0};
		if (ClearCommError(m_hCom,&dwError,NULL)){
			PurgeComm(m_hCom,PURGE_TXABORT|PURGE_TXCLEAR);
			//printf("PurgeComm ok!\n");
		}
		BOOL bReadStatus = FALSE;
		bReadStatus = ReadFile(m_hCom,pReadBuf,dwWantRead,&dwRealRead,&wrOverlapped);
		if (!bReadStatus){
			dwError = GetLastError();
			printf("%d\n",dwError);
			if ( dwError == ERROR_IO_PENDING){
				while(GetOverlappedResult(m_hCom,&wrOverlapped,&dwRealRead,FALSE)){
					printf("dwRealRead = %d\n",dwRealRead);
				}
			}
		}
		//ReadFile(m_hCom,pReadBuf,dwWantRead,&dwRealRead,NULL);
		/*发送数据*/
		if (dwRealRead == 12 && pReadBuf[0] == 0x18 && pReadBuf[1] == 0xDB && pReadBuf[2] ==0x33 && pReadBuf[3] == 0xF1)
		{
			ResponseToECU(pReadBuf,m_hCom,wrOverlapped);
		}
		Sleep(100);
	}

3 个解决方案

#1

 DWORD Serial::Read(void* lpBuf, UINT nCount)
{
	DWORD dwByteRead = 0;	

	if (m_hCommDevice == NULL)
	{
		TRACE(_T("'CSerial::Read': NULL handle !"));
		ASSERT(FALSE);
		return 0;
	}

	if (!ReadFile(m_hCommDevice, lpBuf, nCount, &dwByteRead, NULL))
	{
		/*
		if (GetLastError() == ERROR_HANDLE_EOF)
		AfxThrowSerialCommException(COXSerialCommException::rxTimeout, m_strFileName);
		else {			
		COMSTAT comstat;
		AfxThrowSerialCommException(GetCommException(comstat), m_strFileName);
		}
		*/
		dwByteRead = 0;
	}
	//	TRACE( "Read %d bytes   %02x!!\n",dwByteRead,*(unsigned char *)lpBuf );
	return dwByteRead;
}

 

#2

引用 1 楼 qxw88 的回复:

C/C++ code?1234567891011121314151617181920212223242526 DWORD Serial::Read(void* lpBuf, UINT nCount){    DWORD dwByteRead = 0;         if (m_hCommDevice == NULL)    {        TRACE(_T("'CSe……

你这个是同步操作，但是异步操作的时候readfile没有读到字节 dwByteRead就直接赋值成0了。

#3

顶下 那个高人解答下