Question

VC 调用WaitforSingleObject报错.该怎么处理

Answer 1

////////参考：C/C++ code///////////////////////////////////////////////////////
int CUload::ReadCommBlock(BYTE *pBlock,int nBlockLen)
{  //return 0 if error
   int     WaitErr;
   BOOL    fReadStart;
   COMSTAT ComStat;
   DWORD   dwErrorFlags,dwLength;
   if (!m_bConnected) return 0;
   if (ClearCommError(m_idComDev,&dwErrorFlags,&ComStat))
   {  //ComStat filled
       if (dwErrorFlags) 
       {
           if     (dwErrorFlags & CE_RXOVER)   AfxMessageBox("Receive Queue overflow");            
           else if(dwErrorFlags & CE_OVERRUN)  AfxMessageBox("Receive Overrun Error");            
           else if(dwErrorFlags & CE_RXPARITY) AfxMessageBox("Receive Parity Error");            
           else if(dwErrorFlags & CE_FRAME )   AfxMessageBox("Receive Framing error");            
           else if(dwErrorFlags & CE_BREAK)    AfxMessageBox("Break Detected");            
           else                                AfxMessageBox("CE_OTHERS");
       }
   }
// nBlockLen may >,=,< ComStat.cbInQue !
   dwLength=min((DWORD)nBlockLen,ComStat.cbInQue);
   if(dwLength>0)
   {  // read required
       fReadStart=ReadFile(m_idComDev,pBlock,dwLength,&dwLength,&m_osRead);    
       if(!fReadStart)
       { // if there was a problem, or the async. operation's still pending ... 
           if(GetLastError()==ERROR_IO_PENDING)
           { // asynchronous i/o is still in progress 
               if (WaitErr=WaitForSingleObject(m_osRead.hEvent,60000))// 1 minute
               {  // time over
                   if(WaitErr==WAIT_TIMEOUT) 
                   {  // time out
                       dwLength=0;
                       AfxMessageBox("Time out !");
                   }// end time out
               }// end waiterr
           } // end io_pending
           else
           { // WaitErr=0.if you SetEvent(m_osRead.hEvent) anywhere else
               GetOverlappedResult(m_idComDev,&m_osRead,&dwLength,FALSE);
               m_osRead.Offset +=dwLength;
           }
       }
   } //end if dwLength>0
   return dwLength;
}
// an work thread to monitor the _CTS and RX_CHAR 
UINT CUload::CommWatchRead(LPVOID lpParam)
{   // return 0=OK 1=Error
   CUload     *pUload=(CUload*)lpParam;
   OVERLAPPED    os;
   DWORD        dwEventMask,dwTransfer;
   memset(&os,0,sizeof(OVERLAPPED));
   os.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);// attrb,Manual,init,name
   if (os.hEvent==NULL)
   {
       AfxMessageBox("Can't create Event",MB_ICONSTOP);
       return 1;// error
   }
// set 2 events !
   if (!SetCommMask(pUload->m_idComDev,EV_RXCHAR|EV_CTS)) return 1;
   while (pUload->m_bConnected)
   { // break,only if m_bConnected=NULL 
       dwEventMask=0;
       if(!WaitCommEvent(pUload->m_idComDev,&dwEventMask,&os))
       {    // function fails
           if (GetLastError()==ERROR_IO_PENDING)
           {// TRUE=WaitForSingleObject() should be called inside
               GetOverlappedResult(pUload->m_idComDev,&os,&dwTransfer,TRUE);
               os.Offset+=dwTransfer;
           }
       }
       if((dwEventMask & EV_RXCHAR)==EV_RXCHAR)
       { // some chats received.
            ResetEvent(pUload->m_hPostEventRead);// first reset 
            pUload->PostMessage(WM_COMMNOTIFY,
                                (WPARAM)1,   // EV_RXCHAR
                                (LPARAM)0);  // not used
// wait answer
            WaitForSingleObject(pUload->m_hPostEventRead,0xFFFFFFFF);
       }
// if not at same time,use else if
       if((dwEventMask & EV_CTS)==EV_CTS)
       {  // CTS changed
           ResetEvent(pUload->m_hPostEventRead);// first reset 
           pUload->PostMessage(WM_COMMNOTIFY,
                                (WPARAM)0,   // EV_CTS
                                (LPARAM)0);  // not used
// wait answer
            WaitForSingleObject(pUload->m_hPostEventRead,0xFFFFFFFF);
       }
   }    
   CloseHandle(os.hEvent);
   return 0;// OK
}

Answer 2

参考：
///////////////////////////////////////////////////////
int CUload::ReadCommBlock(BYTE *pBlock,int nBlockLen)
{ //return 0 if error
int WaitErr;
BOOL fReadStart;
COMSTAT ComStat;
DWORD dwErrorFlags,dwLength;

if (!m_bConnected) return 0;

if (ClearCommError(m_idComDev,&dwErrorFlags,&ComStat))
{ //ComStat filled
if (dwErrorFlags)
{
if (dwErrorFlags & CE_RXOVER) AfxMessageBox("Receive Queue overflow");
else if(dwErrorFlags & CE_OVERRUN) AfxMessageBox("Receive Overrun Error");
else if(dwErrorFlags & CE_RXPARITY) AfxMessageBox("Receive Parity Error");
else if(dwErrorFlags & CE_FRAME ) AfxMessageBox("Receive Framing error");
else if(dwErrorFlags & CE_BREAK) AfxMessageBox("Break Detected");
else AfxMessageBox("CE_OTHERS");
}
}
// nBlockLen may >,=,< ComStat.cbInQue !
dwLength=min((DWORD)nBlockLen,ComStat.cbInQue);
if(dwLength>0)
{ // read required
fReadStart=ReadFile(m_idComDev,pBlock,dwLength,&dwLength,&m_osRead);
if(!fReadStart)
{ // if there was a problem, or the async. operation's still pending ...
if(GetLastError()==ERROR_IO_PENDING)
{ // asynchronous i/o is still in progress
if (WaitErr=WaitForSingleObject(m_osRead.hEvent,60000))// 1 minute
{ // time over
if(WaitErr==WAIT_TIMEOUT)
{ // time out
dwLength=0;
AfxMessageBox("Time out !");
}// end time out
}// end waiterr
} // end io_pending
else
{ // WaitErr=0.if you SetEvent(m_osRead.hEvent) anywhere else
GetOverlappedResult(m_idComDev,&m_osRead,&dwLength,FALSE);
m_osRead.Offset +=dwLength;
}
}
} //end if dwLength>0
return dwLength;
}

// an work thread to monitor the _CTS and RX_CHAR
UINT CUload::CommWatchRead(LPVOID lpParam)
{ // return 0=OK 1=Error
CUload *pUload=(CUload*)lpParam;
OVERLAPPED os;
DWORD dwEventMask,dwTransfer;

memset(&os,0,sizeof(OVERLAPPED));
os.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);// attrb,Manual,init,name
if (os.hEvent==NULL)
{
AfxMessageBox("Can't create Event",MB_ICONSTOP);
return 1;// error
}
// set 2 events !
if (!SetCommMask(pUload->m_idComDev,EV_RXCHAR|EV_CTS)) return 1;
while (pUload->m_bConnected)
{ // break,only if m_bConnected=NULL
dwEventMask=0;
if(!WaitCommEvent(pUload->m_idComDev,&dwEventMask,&os))
{ // function fails
if (GetLastError()==ERROR_IO_PENDING)
{// TRUE=WaitForSingleObject() should be called inside
GetOverlappedResult(pUload->m_idComDev,&os,&dwTransfer,TRUE);
os.Offset+=dwTransfer;
}
}
if((dwEventMask & EV_RXCHAR)==EV_RXCHAR)
{ // some chats received.
ResetEvent(pUload->m_hPostEventRead);// first reset
pUload->PostMessage(WM_COMMNOTIFY,
(WPARAM)1, // EV_RXCHAR
(LPARAM)0); // not used
// wait answer
WaitForSingleObject(pUload->m_hPostEventRead,0xFFFFFFFF);
}
// if not at same time,use else if
if((dwEventMask & EV_CTS)==EV_CTS)
{ // CTS changed
ResetEvent(pUload->m_hPostEventRead);// first reset
pUload->PostMessage(WM_COMMNOTIFY,
(WPARAM)0, // EV_CTS
(LPARAM)0); // not used
// wait answer
WaitForSingleObject(pUload->m_hPostEventRead,0xFFFFFFFF);
}
}
CloseHandle(os.hEvent);
return 0;// OK
}