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How to use Cserial ?

Posted on 2001-08-28
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Last Modified: 2008-02-26
Firstly I know hardly any C++ and I'm using VC++ to try and make a little app that will open a com port at a set baud rate.

I was just reading this;
http://www.codeguru.com/network/serial.shtml

but dont know how to put it into action for my purposes.

So far I have a MFC dialog with an edit box for the com port number(m_Port) and one for the baud rate (m_baud)  and a OK button.

Where do I go from here?

This is my first attempt at C++ so please be gentle.
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Question by:xSinbad
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LVL 14

Expert Comment

by:AlexVirochovsky
ID: 6435186
>>Where do I go from here?
...
CSerial serial;
if (serial.Open(m_Port, m_baud))
  {
    AfxMessageBox("Port opened successfully");
    static char* szMessage[] = "This is test data";
     int nBytesSent = serial.SendData(szMessage, strlen  (szMessage));
     ASSERT(nBytesSent == strlen(szMessage));
     serial.Close() ;
  }
else
 AfxMessageBox("Failed to open port!");
...
And download full test project, as sceleton
of your  Apps.
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Author Comment

by:xSinbad
ID: 6435202
Ok Im guessing that I have to stick that after this;
void CSerialSetDlg::OnOK()

I download the serial.h and serial.cpp , what do I do with them?
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Expert Comment

by:AlexVirochovsky
ID: 6435259
serial.h save in your directory and add in begin
of you code next line:
#include  "serial.h"
serial.c you can use for references.
>>Ok Im guessing that I have to stick that after this;
void CSerialSetDlg::OnOK()
Yes.
>>This is my first attempt at C++ so please be gentle.
I recomend you spend some time to understand serial.c and read some good tutorial
by C++. Next is small list:
Relisoft (C++) : http://www.relisoft.com/index.htm
http://www.eckelobjects.com/ThinkingInCPP2e.html
http://www.aul.fiu.edu/tech/visualc.html
http://www.swcp.com/~dodrill/cppdoc/cpplist.htm
http://www.mcp.com
http://www.cprogramming.com/tutorial.html
http://www.strath.ac.uk/CC/Courses/OldCcourse/tableofcontents3_1.html
http://www.athena.auth.gr/doc/ctutorial/tutorial.html
http://www.itlibrary.com
http://www.macaskill.com/freebooks/freebooks.html
(must register free).
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LVL 6

Author Comment

by:xSinbad
ID: 6438860
Ok tried that and recieved these errors;

--------------------Configuration: Serial Set - Win32 Debug--------------------
Compiling...
Serial SetDlg.cpp
C:\Program Files\Microsoft Visual Studio\MyProjects\Serial Set\Serial SetDlg.cpp(103) : error C2440: 'initializing' : cannot convert from 'char [18]' to 'char *[]'
        There is no context in which this conversion is possible
C:\Program Files\Microsoft Visual Studio\MyProjects\Serial Set\Serial SetDlg.cpp(104) : error C2664: 'strlen' : cannot convert parameter 1 from 'char *[]' to 'const char *'
        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
C:\Program Files\Microsoft Visual Studio\MyProjects\Serial Set\Serial SetDlg.cpp(104) : error C2664: 'SendData' : cannot convert parameter 1 from 'char *[]' to 'const char *'
        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
C:\Program Files\Microsoft Visual Studio\MyProjects\Serial Set\Serial SetDlg.cpp(105) : error C2664: 'strlen' : cannot convert parameter 1 from 'char *[]' to 'const char *'
        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
Error executing cl.exe.

Serial SetDlg.obj - 4 error(s), 0 warning(s)
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Expert Comment

by:AlexVirochovsky
ID: 6439587
Change
>> static char* szMessage[] = "This is test data";
To
 char* szMessage = "This is test data";
   
That is reason to all 4 errors
   
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Expert Comment

by:RideOn
ID: 6439591
u could also use WinAPI for serial communications.
if the CSerial solution won't work, let me know and i'll give u my class i wrote...

=:=RideOn
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Author Comment

by:xSinbad
ID: 6442961
OK this is what I have;

void CSerialSetDlg::OnOK()
{
CSerial serial;
if (serial.Open(m_Port, 76800))
 {
   AfxMessageBox("Port opened successfully");
   char* szMessage = "This is test data";

    int nBytesSent = serial.SendData(szMessage, strlen  (szMessage));
    ASSERT(nBytesSent == strlen(szMessage));
    serial.Close() ;
 }
else
AfxMessageBox("Failed to open port!");


}




Here are the errors returned;

Compiling...
Serial SetDlg.cpp
C:\Program Files\Microsoft Visual Studio\MyProjects\Serial Set\Serial SetDlg.cpp(106) : warning C4018: '==' : signed/unsigned mismatch
Linking...
Serial SetDlg.obj : error LNK2001: unresolved external symbol "public: __thiscall CSerial::~CSerial(void)" (??1CSerial@@QAE@XZ)
Serial SetDlg.obj : error LNK2001: unresolved external symbol "public: int __thiscall CSerial::Close(void)" (?Close@CSerial@@QAEHXZ)
Serial SetDlg.obj : error LNK2001: unresolved external symbol "public: int __thiscall CSerial::SendData(char const *,int)" (?SendData@CSerial@@QAEHPBDH@Z)
Serial SetDlg.obj : error LNK2001: unresolved external symbol "public: int __thiscall CSerial::Open(int,int)" (?Open@CSerial@@QAEHHH@Z)
Serial SetDlg.obj : error LNK2001: unresolved external symbol "public: __thiscall CSerial::CSerial(void)" (??0CSerial@@QAE@XZ)
Debug/Serial Set.exe : fatal error LNK1120: 5 unresolved externals
Error executing link.exe.
Creating browse info file...

Serial Set.exe - 6 error(s), 1 warning(s)


RideOn, the reason Im doing this is to help out someone in another question. And they need to set the serial port speed to 76800, I have searched the M$ knowledge base long and hard for info on doing this(API would have been great) and 76800 baud is appparently not a constant in the MS comm driver. But by using Cserial I supposedly can acheive this speed.
Im a VB/VBA developer and I thought it was time to take the step up and this is a good a time as any to start...

Sorry for all the suffing around, will up the points to the max.


Cheers
Marcus
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LVL 14

Accepted Solution

by:
AlexVirochovsky earned 300 total points
ID: 6443642
O, you need add file serial.c in your project.

Or in end of your code add next:
CSerial::CSerial()
{

      memset( &m_OverlappedRead, 0, sizeof( OVERLAPPED ) );
       memset( &m_OverlappedWrite, 0, sizeof( OVERLAPPED ) );
      m_hIDComDev = NULL;
      m_bOpened = FALSE;

}

CSerial::~CSerial()
{

      Close();

}

BOOL CSerial::Open( int nPort, int nBaud )
{

      if( m_bOpened ) return( TRUE );

      char szPort[15];
      char szComParams[50];
      DCB dcb;

      wsprintf( szPort, "COM%d", nPort );
      m_hIDComDev = CreateFile( szPort, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL );
      if( m_hIDComDev == NULL ) return( FALSE );

      memset( &m_OverlappedRead, 0, sizeof( OVERLAPPED ) );
       memset( &m_OverlappedWrite, 0, sizeof( OVERLAPPED ) );

      COMMTIMEOUTS CommTimeOuts;
      CommTimeOuts.ReadIntervalTimeout = 0xFFFFFFFF;
      CommTimeOuts.ReadTotalTimeoutMultiplier = 0;
      CommTimeOuts.ReadTotalTimeoutConstant = 0;
      CommTimeOuts.WriteTotalTimeoutMultiplier = 0;
      CommTimeOuts.WriteTotalTimeoutConstant = 5000;
      SetCommTimeouts( m_hIDComDev, &CommTimeOuts );

      wsprintf( szComParams, "COM%d:%d,n,8,1", nPort, nBaud );

      m_OverlappedRead.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );
      m_OverlappedWrite.hEvent = CreateEvent( NULL, TRUE, FALSE, NULL );

      dcb.DCBlength = sizeof( DCB );
      GetCommState( m_hIDComDev, &dcb );
      dcb.BaudRate = nBaud;
      dcb.ByteSize = 8;
      unsigned char ucSet;
      ucSet = (unsigned char) ( ( FC_RTSCTS & FC_DTRDSR ) != 0 );
      ucSet = (unsigned char) ( ( FC_RTSCTS & FC_RTSCTS ) != 0 );
      ucSet = (unsigned char) ( ( FC_RTSCTS & FC_XONXOFF ) != 0 );
      if( !SetCommState( m_hIDComDev, &dcb ) ||
            !SetupComm( m_hIDComDev, 10000, 10000 ) ||
            m_OverlappedRead.hEvent == NULL ||
            m_OverlappedWrite.hEvent == NULL ){
            DWORD dwError = GetLastError();
            if( m_OverlappedRead.hEvent != NULL ) CloseHandle( m_OverlappedRead.hEvent );
            if( m_OverlappedWrite.hEvent != NULL ) CloseHandle( m_OverlappedWrite.hEvent );
            CloseHandle( m_hIDComDev );
            return( FALSE );
            }

      m_bOpened = TRUE;

      return( m_bOpened );

}

BOOL CSerial::Close( void )
{

      if( !m_bOpened || m_hIDComDev == NULL ) return( TRUE );

      if( m_OverlappedRead.hEvent != NULL ) CloseHandle( m_OverlappedRead.hEvent );
      if( m_OverlappedWrite.hEvent != NULL ) CloseHandle( m_OverlappedWrite.hEvent );
      CloseHandle( m_hIDComDev );
      m_bOpened = FALSE;
      m_hIDComDev = NULL;

      return( TRUE );

}

BOOL CSerial::WriteCommByte( unsigned char ucByte )
{
      BOOL bWriteStat;
      DWORD dwBytesWritten;

      bWriteStat = WriteFile( m_hIDComDev, (LPSTR) &ucByte, 1, &dwBytesWritten, &m_OverlappedWrite );
      if( !bWriteStat && ( GetLastError() == ERROR_IO_PENDING ) ){
            if( WaitForSingleObject( m_OverlappedWrite.hEvent, 1000 ) ) dwBytesWritten = 0;
            else{
                  GetOverlappedResult( m_hIDComDev, &m_OverlappedWrite, &dwBytesWritten, FALSE );
                  m_OverlappedWrite.Offset += dwBytesWritten;
                  }
            }

      return( TRUE );

}

int CSerial::SendData( const char *buffer, int size )
{

      if( !m_bOpened || m_hIDComDev == NULL ) return( 0 );

      DWORD dwBytesWritten = 0;
      int i;
      for( i=0; i<size; i++ ){
            WriteCommByte( buffer[i] );
            dwBytesWritten++;
            }

      return( (int) dwBytesWritten );

}

int CSerial::ReadDataWaiting( void )
{

      if( !m_bOpened || m_hIDComDev == NULL ) return( 0 );

      DWORD dwErrorFlags;
      COMSTAT ComStat;

      ClearCommError( m_hIDComDev, &dwErrorFlags, &ComStat );

      return( (int) ComStat.cbInQue );

}

int CSerial::ReadData( void *buffer, int limit )
{

      if( !m_bOpened || m_hIDComDev == NULL ) return( 0 );

      BOOL bReadStatus;
      DWORD dwBytesRead, dwErrorFlags;
      COMSTAT ComStat;

      ClearCommError( m_hIDComDev, &dwErrorFlags, &ComStat );
      if( !ComStat.cbInQue ) return( 0 );

      dwBytesRead = (DWORD) ComStat.cbInQue;
      if( limit < (int) dwBytesRead ) dwBytesRead = (DWORD) limit;

      bReadStatus = ReadFile( m_hIDComDev, buffer, dwBytesRead, &dwBytesRead, &m_OverlappedRead );
      if( !bReadStatus ){
            if( GetLastError() == ERROR_IO_PENDING ){
                  WaitForSingleObject( m_OverlappedRead.hEvent, 2000 );
                  return( (int) dwBytesRead );
                  }
            return( 0 );
            }

      return( (int) dwBytesRead );

}

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Author Comment

by:xSinbad
ID: 6449387
Another warning....

Serial SetDlg.cpp
C:\Program Files\Microsoft Visual Studio\MyProjects\Serial Set\Serial SetDlg.cpp(106) : warning C4018: '==' : signed/unsigned mismatch

Serial SetDlg.obj - 0 error(s), 1 warning(s)


This occurs in the following line

    ASSERT(nBytesSent == strlen(szMessage));
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LVL 6

Author Comment

by:xSinbad
ID: 6449397
It doesnt appear to work but that is not your your fault. Thank you very much for your help.

Cheers
Marcus
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