我参照例子, 用CREATEFILE取的COM1的HANDLE, 然后设置其配置, 最后, 用READFILE来获取COM1的数据, 但是, 每次一到READFILE, 就会报 INVALID HANDLE的错误, why?

大致代码:
//取得COM1的HANDLE
HANDLE m_Port = CreateFile("COM1:",GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
if (m_Port == INVALID_HANDLE_VALUE){
// Handle the error.
return false ;
}

// 配置COM1
DCB dcb;

if (!GetCommState(m_Port, &dcb)){
return false;
}

dcb.BaudRate = CBR_9600; // set the baud rate
dcb.ByteSize = 8; // data size, xmit, and rcv
dcb.Parity = NOPARITY; // no parity bit
dcb.StopBits = ONESTOPBIT; // one stop bit

if (!SetCommState(m_Port, &dcb)){
return false;
}

//读取数据
char input[200];
unsigned int lenBuff = 200;
LPDWORD lenMessage;

String *strResult;

if(ReadFile(m_Port,input,lenBuff,lenMessage,NULL)==0){ //这里会有EXCEPTION
return false;
}

- 连DLL库了吗？ (别问我怎么连 http://chinasmile.infopop.net/infopo...icon_smile.gif )

- 关COM1了吗？是不是机器启动第一次行，以后再不行了？每次要Closehandle

- 别的问题就该查书了 http://chinasmile.infopop.net/infopo...icon_frown.gif

连什么DLL? 我只是用了: #INCLUDE <WINDOWS.H> 这个是WIN32的API吧?

怎么都不行, CLOSEHANDLE也不行.

该查什么书呢? MICROSOFT的MSDN我都看了无数遍了...

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by rainzw:
连什么DLL? 我只是用了: #INCLUDE &lt;WINDOWS.H&gt; 这个是WIN32的API吧?

怎么都不行, CLOSEHANDLE也不行.

该查什么书呢? MICROSOFT的MSDN我都看了无数遍了... <HR></BLOCKQUOTE>

Hehe. MSDN is so big library. Countless? Beat me hard.
oK.

if(ReadFile(m_Port,input,lenBuff,lenMessage,NULL)==0){ //这里会有EXCEPTION
return false;
}

THE ERROR::::
lenMessage IS A POINTER. Initialize before invocation of the function.


Changed to:

DWORD lenMessage;

String *strResult;

if(ReadFile(m_Port,input,lenBuff,&lenMessage,NULL)==0){

Another thing:

I am seasoned windows programmer.
I wrote this kind of programs countless times.
But I just forgot it when I didn't write this program for months.

I once wrote serial driver for MS.
I know there is still a bug in MS windows.

But I just cannot remmember anything about the syntax of COMM usage.

But I can guess the place where you are wrong, because you are not a competent programmer.

Suggest you consider your future as a C programmer.