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为什么无法关闭串口啊??

楼主vmaster（似水浮云）2005-03-07 18:59:59 在 VC/MFC / 基础类提问

代码如下:

全局变量:
BYTE cRBuff[512];
DWORD cBytes;
BYTE ch;
CString strRecv;
HANDLE hComPort;
bool ExitFlag;
DWORD dwThreadID;
HANDLE m_hCommThread;

函数开始:
void TestThread()
{
DWORD Errors;
COMSTAT ComStat;
hComPort=CreateFile(TEXT("COM2:"),GENERIC_READ,0,NULL,OPEN_EXISTING,0,NULL);
if (hComPort == NULL)
{//如果无法创建串口，取错误信息，显示提示
DWORD dwError = GetLastError();
AfxMessageBox(TEXT("Unable to open the serial port\n"));
return;
}

SetCommMask(hComPort, EV_RXCHAR | EV_BREAK);
//SetupComm(hComPort,READBUFLEN,WRITEBUFLEN);
COMMTIMEOUTS CommTimeouts; // Comm port timeouts structure

// Retrieve the timeouts parameters for all read and write operations on the port.
GetCommTimeouts (hComPort, &CommTimeouts);

// Change the COMMTIMEOUTS structure settings.
CommTimeouts.ReadIntervalTimeout = MAXDWORD;
CommTimeouts.ReadTotalTimeoutMultiplier = 0;
CommTimeouts.ReadTotalTimeoutConstant = 0;
// Set the timeouts parameters for all read and write operations on the port.
if (!SetCommTimeouts (hComPort, &CommTimeouts))
{
// Could not create the read thread.
MessageBox (NULL, TEXT("Unable to set the time-out parameters"),
TEXT("Error"), MB_OK);
// dwError = GetLastError ();
return;
}

// DWORD dwError;
DCB PortDCB;

// Get the default port setting information.
GetCommState(hComPort, &PortDCB);

// Change the DCB structure settings.
//PortDCB.DCBlength = sizeof (DCB);
PortDCB.BaudRate = CBR_4800; // Current baud
PortDCB.ByteSize = 8; // Number of bits/byte, 4-8
PortDCB.Parity = ODDPARITY; // 0-4=no,odd,even,mark,space
PortDCB.StopBits = ONESTOPBIT; // 0,1,2 = 1, 1.5, 2

// Configure the port according to the specifications of the DCB
// structure.
if (! SetCommState(hComPort, &PortDCB))
{
MessageBox (NULL, TEXT("Unable to configure the CommState"),
TEXT("Error"), MB_OK);
// dwError = GetLastError ();
return;
}

// Direct the port to perform extended functions SETDTR and SETRTS
// SETDTR: Sends the DTR (data-terminal-ready) signal.
// SETRTS: Sends the RTS (request-to-send) signal.
// EscapeCommFunction (hComPort, SETDTR);
// EscapeCommFunction (hComPort, SETRTS);

//
DWORD dwCommMask = 0;
int ctrBuff=0;
while(!ExitFlag) //退出线程的标记,用于退出按钮
{
// strRecv=TEXT("");

WaitCommEvent(hComPort, &dwCommMask, NULL);
if (! ClearCommError(hComPort, &Errors, &ComStat))
continue;
if (dwCommMask & EV_BREAK) break;
if (dwCommMask & EV_RXCHAR)
{
ReadFile(hComPort, &ch, 1, &cBytes,NULL);
//memset(&cRBuff, 0, sizeof (cRBuff));
if (ctrBuff==512)
{
strRecv=(CString)cRBuff;
ctrBuff=0;
}
cRBuff[ctrBuff]=ch;

ctrBuff++;
}
}
SetCommMask(hComPort,NULL);
if (CloseHandle(hComPort)!=0) AfxMessageBox(TEXT("CloseHandle success.")); //关闭串口返回成功
return;
}

为什么每次第2次执行程序都是无法打开端口呢,而且很慢,资源耗得很严重??
另外:我的串口是一直有数据进来的... 问题点数：60、回复次数：11Top

1 楼legendhui（秋天的叶子）回复于 2005-03-07 22:17:23 得分 10

你的程序有内存泄露，你在退出进程前，应该关闭所有资源Top

2 楼samp_miao（九天揽月）回复于 2005-03-08 08:41:40 得分 8

if (hComPort == NULL)
{//如果无法创建串口，取错误信息，显示提示
DWORD dwError = GetLastError();
AfxMessageBox(TEXT("Unable to open the serial port\n"));
return;
}
打开串口失败时，返回INVALID_HANDLE_VALUE,不是NULL.

但是应该是其他原因吧，Top

3 楼yuanbocsut（井冈星火）回复于 2005-03-08 10:27:03 得分 2

upTop

4 楼tudou614（魔蟹座的SATAN）回复于 2005-03-08 10:27:11 得分 2

UPTop

5 楼vmaster（似水浮云）回复于 2005-03-08 10:47:50 得分 0

在线等...Top

6 楼crystal521（【云淡风轻】）回复于 2005-03-08 13:04:54 得分 5

你第二次打开线程时有没有关闭上次的线程？Top

7 楼crystal521（【云淡风轻】）回复于 2005-03-08 13:17:55 得分 15

改了一下
void TestThread()
{
DWORD Errors;
COMSTAT ComStat;
hComPort=CreateFile(TEXT("COM2:"),GENERIC_READ,0,NULL,OPEN_EXISTING,0,NULL);
if (hComPort == INVALID_HANDLE_VALUE)
{//如果无法创建串口，取错误信息，显示提示
DWORD dwError = GetLastError();
AfxMessageBox(TEXT("Unable to open the serial port\n"));
return;
}

SetCommMask(hComPort, EV_RXCHAR | EV_BREAK);

COMMTIMEOUTS CommTimeouts; // Comm port timeouts structure

GetCommTimeouts (hComPort, &CommTimeouts);

CommTimeouts.ReadIntervalTimeout = MAXDWORD;
CommTimeouts.ReadTotalTimeoutMultiplier = 0;
CommTimeouts.ReadTotalTimeoutConstant = 0;

if (!SetCommTimeouts (hComPort, &CommTimeouts))
{
MessageBox (NULL, TEXT("Unable to set the time-out parameters"),
TEXT("Error"), MB_OK);
return;
}

DCB PortDCB;

GetCommState(hComPort, &PortDCB);

PortDCB.BaudRate = CBR_4800; // Current baud
PortDCB.ByteSize = 8; // Number of bits/byte, 4-8
PortDCB.Parity = ODDPARITY; // 0-4=no,odd,even,mark,space
PortDCB.StopBits = ONESTOPBIT; // 0,1,2 = 1, 1.5, 2

if (! SetCommState(hComPort, &PortDCB))
{
MessageBox (NULL, TEXT("Unable to configure the CommState"),
TEXT("Error"), MB_OK);
return;
}

DWORD dwCommMask = 0;
int ctrBuff=0;
while(!ExitFlag)
{
WaitCommEvent(hComPort, &dwCommMask, NULL);
if (! ClearCommError(hComPort, &Errors, &ComStat))
continue;
if (dwCommMask & EV_BREAK) break;
if (dwCommMask & EV_RXCHAR)
{
ReadFile(hComPort, &ch, ComStat.cbInQue, &cBytes,NULL);
if (ctrBuff==512)
{
strRecv=(CString)cRBuff;
ctrBuff=0;
}
cRBuff[ctrBuff]=ch;

ctrBuff++;
}
}
SetCommMask(hComPort,NULL);
if (CloseHandle(hComPort)!=0) AfxMessageBox(TEXT("CloseHandle success.")); //关闭串口返回成功
AfxEndThread(0);
return;
}Top

8 楼crystal521（【云淡风轻】）回复于 2005-03-08 13:19:45 得分 8

还有检查一下你的cRBuff和ch类型及转换，看有没有内存泄漏Top

9 楼vmaster（似水浮云）回复于 2005-03-08 13:39:28 得分 0

线程有自己返回,那算不算自动退出呢,还是要加上这一句呢?:
PostThreadMessage(GetCurrentThreadId(),WM_QUIT,0,0); //退出线程
Top

10 楼vmaster（似水浮云）回复于 2005-03-08 13:57:01 得分 0

还是不行,运行一次可以,但再运行7,8遍就不行了,突然变得好慢...
请问怎么检查内存泄漏的??Top

11 楼nuaawenlin（飘人）回复于 2005-03-09 10:20:41 得分 10

有内存泄露

在调试窗口中可以看到Top