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Description, HelpContext, HelpFile, NativeError, Number, Source, and SQLState Properties Example (VC++)

This example triggers an error, traps it, and displays the Description, HelpContext, HelpFile, NativeError, Number, Source, and SQLState properties of the resulting Error object.

// BeginDescriptionCpp.cpp
// compile with: /EHsc
#import "msado15.dll" no_namespace rename("EOF", "EndOfFile")

// Function declarations
inline void TESTHR(HRESULT x) {if FAILED(x) _com_issue_error(x);};
void DescriptionX();
void PrintProviderError(_ConnectionPtr pConnection);
void PrintComError(_com_error &e);

int main() {
   if (FAILED(::CoInitialize(NULL)))
      return -1;

   DescriptionX();
   ::CoUninitialize();
}

void DescriptionX() {
   // Define ADO object pointers. Initialize pointers on define. These are in the ADODB::  namespace
   _ConnectionPtr pConnection = NULL;
   ErrorPtr errorLoop = NULL;

   // Define Other Variables
   HRESULT hr = S_OK;

   try {
      // Intentionally trigger an error.  open connection
      TESTHR(pConnection.CreateInstance(__uuidof(Connection)));

      if (FAILED(hr = pConnection->Open("Nothing", "", "", adConnectUnspecified))) {
         _com_issue_error(hr);
         exit(1);
      }

      // Cleanup object before exit.
      pConnection->Close();
   }
   catch(_com_error) {
      // Pass a connection pointer.
      PrintProviderError(pConnection);
   }
}

void PrintProviderError(_ConnectionPtr pConnection) {
   // Define Other Variables
   HRESULT hr = S_OK;
   _bstr_t strError;
   ErrorPtr pErr = NULL;

   try {
      // Enumerate Errors collection and display properties of each Error object.
      long nCount = pConnection->Errors->Count;

      // Collection ranges from 0 to nCount - 1.
      for ( long i = 0 ; i < nCount ; i++ ) {
         pErr = pConnection->Errors->GetItem(i);
         printf("Error #%d\n", pErr->Number);
         printf(" %s\n", (LPCSTR)pErr->Description);
         printf(" (Source: %s)\n", (LPCSTR)pErr->Source);
         printf(" (SQL State: %s)\n", (LPCSTR)pErr->SQLState);
         printf(" (NativeError: %d)\n", (LPCSTR)pErr->NativeError);

         if ((LPCSTR)pErr->GetHelpFile() == NULL)
            printf("\tNo Help file available\n");
         else {
            printf("\t(HelpFile: %s\n)" ,pErr->HelpFile);
            printf("\t(HelpContext: %s\n)" , pErr->HelpContext);
         }
      }
   }

   catch(_com_error &e) {
      // Notify the user of errors if any.
      PrintComError(e);
   }
}

void PrintComError(_com_error &e) {
   // Notify the user of errors if any.
   _bstr_t bstrSource(e.Source());
   _bstr_t bstrDescription(e.Description());

   // Print Com errors.
   printf("Error\n");
   printf("\tCode = %08lx\n", e.Error());
   printf("\tCode meaning = %s", e.ErrorMessage());
   printf("\tSource = %s\n", (LPCSTR) bstrSource);
   printf("\tDescription = %s\n", (LPCSTR) bstrDescription);
}
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