Error Handling

Error handling functions. More...

Functions
VOID	BCGetErrorText (ERRCODE eCode, LPSTR szText, size_t nSize)
	Returns error text to given error-code.
VOID	BCGetErrorTextExt (t_BarCode *pBarCode, ERRCODE eCode, LPSTR szText, size_t nSize)
	Returns extended error text to given error-code.
INT	BCGet_InvalidDataPos (t_BarCode *pBarCode)
	Gets position of invalid character in input data.

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Detailed Description

Error handling functions.

Error Codes

Here is a list of error-codes which are used by TBarCode and may be returned to the user. Operating system specific error-codes are not listed. Error codes are specified in hexadecimal notation (0x). If any of the BCxxxx functions returns an error code not equal to zero (ErrOk) than DO NOT call subsequent BCxxxx functions except of BCFree(). An error code indicates an error condition and subsequent calls (except to BCFree) may fail and produce unexpected results.

• 0x00000000 ErrOK = No Error
• 0x80004001 Barcode type not implemented (see BCSetBCType())
• 0x80070032 Not supported
• 0x80070057 Invalid parameter or unsupported value
• 0x8007000D Wrong character (see BCSetBCType())
• 0x80090004 Wrong number of input characters (see BCSetBCType())
• 0x80090005 Invalid number of input characters in combination with Composite Component
• 0x8007007A Input string too long
• 0x80040140 Barcode does not fit into bounding rectangle (see BCSetMustFit())
• 0x800710d2 No input characters

Error Handling

This chapter demonstrates proper error-handling. It shows how to create an appropriate error message if you receive an error code from BCCreate()

 CString GetFullBCErrorText
 (
 t_BarCode* pBarCode,   // IN: pointer to barcode struct
 ERRCODE eCode          // IN: last occurred error code
 )
 {
 CString sErrorText;
 TCHAR szBuffer[70] = {0};
 LPTSTR szErrorMsg = szBuffer;
 CString sWrongChar;
 LPTSTR szCCError = _T("");
 
   BCGetErrorText(eCode, szBuffer, (sizeof(szBuffer)/sizeof(szBuffer[0]))-1);     // retrieve error information
   if (BCGet_2DCompositeComponent(pBarCode) != eCC_None)                          // was a composite symbol requested? 
   {
     BOOL bErrinCC = BCGet_CompSym_ErrorInCC(pBarCode);
     // error in the composite or linear component?
     szCCError =  bErrinCC ? _T("in 2D Composite Component") : _T("in linear component") ;
     // maybe a composite component was requested, which is not allowed for the basic linear barcode type 
     if (bErrinCC && eCode == W32toTEC(ERROR_NOT_SUPPORTED))
     {
       szCCError = _T("in Composite Symbology");
       szErrorMsg = _T("Composite Component not supported for the selected barcode type");
      }
   }
 
   // or the user supplied invalid data (not all characters can be encoded with the selected barcode type)
   if (eCode == W32toTEC(ERROR_INVALID_DATA))
   {
     INT nPos = BCGet_InvalidDataPos(pBarCode);
     CString sData = GetDocument()->GetData();
     CString sHex;
 
     // show the wrong character
     if (nPos >= 0 && nPos < sData.GetLength())
     {
       if (!isgraph(sData.GetAt(nPos)))
         sHex.Format(" (ASCII Code 0x%X)", sData.GetAt(nPos) & 0xff);
       sWrongChar.Format("'%c' at position %d%s", sData.GetAt(nPos) & 0xff, nPos+1, sHex);
     }
   }
   else if (eCode == NTE_BAD_LEN)
   {
     // barcode needs a specific number of input characters
     // retrieve number of needed characters (data + check-digit)
     INT nLen = BCGetMaxLenOfData(BCGetBCType(pBarCode));
 
     // check if wrong character position is available (-1 = not available)
     if (nLen > 0)
     {
       INT nLenCD = BCGetCheckDigits(pBarCode, NULL, 0); 

       nLenCD = (nLenCD < 0) ? 0 : nLenCD;
       // the check-digit need not to be part of input data
       sWrongChar.Format(" (needs %d chars)", nLen - nLenCD);
     }
   }
   // this would be our final error message to the user
   sErrorText.Format(_T("Error %s: %s%s!"), szCCError, (LPCSTR) szErrorMsg, sWrongChar); //FormatMessage
   return sErrorText;
 }

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Generated on Thu Dec 7 13:38:29 2006 for TEC-IT TBarCode Library 7.0.4 with doxygen 1.4.7