🚀 go-pugleaf

Here is a snippet of my code and exactly what I am doing:

1.  Is where I am writing and reading.
2.  Is my actual read.



// Set the unit on programming mode
 clComm.Write("C",1);

 do
  {
   clComm.Read(1);
   cResponse = NULL;
   cResponse = clComm.cTransBuff;
   if (iRead_Tries >= 3)
    goto No_Response;
   iRead_Tries++;
  }
 // Wait for 0x0D
 while (cResponse[0] != 0x0D);





//--------------------------------------------------------------------------
----
// Read from COM port
//--------------------------------------------------------------------------
----
void __fastcall Comm::Read(unsigned int iExpected)
{
 // Initialize
 iCollectBytes = 0;
 dwActualBytesRead = 0;
 bStop_Read = false;
 COMSTAT comstat;            // Structure of the communication device

 // Do we have the handle ?
 if (hComm)
  { // Begin if statement (Handle)

    // Clear the buffers
    for (int i = 0; i <= (BUFSIZE - 1); i++)
     bCommData[i] = NULL;
    for (int i = 0; i <= (BUFSIZE - 1); i++)
     cTransBuff[i] = NULL;

    // Set a safety timeout
    dwRead_Time_Out = GetTickCount() + (iExpected*2);

    // Stop read flag
    while (bStop_Read == false)
     { // Begin while statement (Stop Read Flag)

       // Do we have the handle ?
       //if (hComm)
       // Clear any communication error & return # of bytes in the input
buffer
       ClearCommError(hComm,     // handle to communications device
                      &dwError,  // pointer to variable to receive error
codes
                      &comstat); // pointer to buffer for communications
status


       // Is there anything waiting to be read (BUFSIZE bytes match
cCommData
       //capability)
       if ((comstat.cbInQue >= iExpected)  && (comstat.cbInQue <= BUFSIZE))
        { // Begin if statement (InQue)

          // Do we have the handle ?
          //if (hComm)
          // Read the data from the serial port
          if (!ReadFile (hComm,
                         bCommData,
                         comstat.cbInQue,
                         &dwBytesTransferred,
                         &o))

           { // Begin if statement (read error)

             // Check if error is Overlapped I/O pending
             if (!(GetLastError() == ERROR_IO_PENDING))

             // Report the error
             ReportError();

           } // End if statement (read error)

          else
           { // Begin else statement (Bytes are waiting)

             // Return the number of bytes that were read
             GetOverlappedResult(hComm,
                                 &o,
                                 &dwActualBytesRead,
                                 FALSE);

             // Are there bytes waiting and check if buffer is not overrun
             if ((dwActualBytesRead != 0) && (dwActualBytesRead <= BUFSIZE))
              { // Begin if statement (actual bytes read)

                // Start the collection of bytes
                for (unsigned int i = 0; i <= (dwActualBytesRead - 1); i++)
                 { // Begin for statement (byte collect)

                   // Copy the data to the return variable
                   cTransBuff[iCollectBytes++] = bCommData[i];

                 } // End for statement (byte collect)

              } // End if statement (actual bytes read)

           } // End else statement (Byte are waiting)
        } // End if statement (InQue)

       // Safety timeout check
       if (dwRead_Time_Out <= GetTickCount())
       // End the read while loop
       bStop_Read = true;

     } // End while statement (Stop Read Flag)
    } // End if statement (Handle)
}


It probably looks pretty weird, but I am not an expert.  It works if
iRead_Tries is a number like 10, but that means according to my code that if
I am running my communication at 9600 baud, and I am expecting 1 byte and I
am multiplying by two, enough so that it will read it the first time and not
even have to get to three.
So I believe, that Windows does not report right away to the struct
__COMSTA,  there is actually a delay of some sort?  I can't put my finger on
it, but maybe you guys can see something I am doing wrong with this snippet
of code.

By the way, I am not always expecting one byte coming back, that is why, my
readfile has comstat.cbInQue, as the number of bytes to read.

Thank you,
Neil P.