串口写不进数据 看看如何解决

Question

第一次用 VC 不熟悉  调试下面程序有问题 望能指教void CCommonDlg::Onpara() // 读24c16 里的网络参数；
{
OVERLAPPED osWrite = {0};
    DWORD dwWritten;
DWORD dwRes;
//OVERLAPPED osReader = {0};
DWORD dwRead;
int b[18];
int a[18];
a[0]=0x3e;
a[1]=0x04;
osWrite.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
         if (osWrite.hEvent == NULL)   return;
         WriteFile(hComm, a, 18, &dwWritten, &osWrite);

int aaa=GetLastError();  // aaa 错误代号为 997为何 WriteFile  函数写不进？  

Answer 1

// 997 是 ERROR_IO_PENDING
if (aaa == ERROR_IO_PENDING) 
    if ( GetOverlappedResult(hComm, &osWrite, &dwWritten, TRUE) ) 
        // OK
    else 
        // Error

Answer 2

int aaa=GetLastError();  // aaa 错误代号为 997这是 为了知道 到底 什么错了  查了 997 的 错误说明 楼上说的  不是很明白？俺贴的 代码  如何 才能 写串口参数 成功？谢谢

Answer 3

void CCommonDlg::Onpara() // 读24c16 里的网络参数；
{
// TODO: Add your control notification handler code here
OVERLAPPED osWrite = {0};
    DWORD dwWritten;
DWORD dwRes;
//OVERLAPPED osReader = {0};
DWORD dwRead;
int b[18];
int a[18];
a[0]=0x3e;
a[1]=0x04;
osWrite.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
   if (osWrite.hEvent == NULL)   return;
    WriteFile(hComm, a, 18, &dwWritten, &osWrite);
if ( GetOverlappedResult(hComm, &osWrite, &dwWritten, TRUE) ) 
{ 
123 AfxMessageBox ("ok");  //这里显示成功了  就是说发下去的
                                         // 命令成功 即 0x3E 0x04
}// OK
    else 
{
AfxMessageBox ("error");
}


   这个函数ReadFile(hComm, b, 18, &dwRead, &osReader);
 既 收  24c16里的 参数 这么写对不？ 放 123 处么？
见笑啦   第一次用VC   

}

Answer 4

BOOL bRet = WriteFile(hComm, a, 18, &dwWritten, &osWrite);
if ( !bRet ) {
    iError = GetLastError();
    if ( iError == ERROR_IO_PENDING ) {
        bRet = GetOverlappedResult(hComm, &osWrite, &dwWritten, TRUE);
    }
}if ( bRet ) {  // 发送成功
    COMSTAT stComStat;
    DWORD dwErrorFlag;
    ClearCommError(hComm, &dwErrorFlag, &stComStat);
    if ( stComStat.cbInQue > 0 ) { // 串口有数据
        bRet = ReadFile(hComm, b, 18, &dwRead, &osReader);
        if ( bRet ) {
            bRet = GetOverlappedResult(hComm, &osReader, &dwRead, FALSE);
        }
    }
}