Inside Server-Based Applications Comments and Corrections (262108)

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CD-ROM: Sample Code Corrections For ODBClass.cpp

Several of the sample applications that use ODBClass.cpp may fail. The problem is in the bindColumn function. It currently returns a pointer to the local variable retLen, which later causes the SQLFetch function to return random information.

None of this code appears in the book; it's only in the projects on the CD-ROM. The ODBClass.cpp file is used in the Chapter 8 ODBCTest project, the Chapter 10 ISAPIPhone project, the Chapter 11 FilterRaw project, the Chapter 14 MonitorService and TestMonitor projects, and the Chapter 15 MonitorService project.

In each project, change the bindColumn function in the ODBClass.cpp file from:

RETCODE CODBCCursor::bindColumn(UWORD& col, char *columnName,
    SDWORD len, SWORD type)
{
    SDWORD retLen;
    EnterCriticalSection(&CriticalSection);
    col = assignColumn(columnName, len);
    colInfo[col]->type = type;
    LeaveCriticalSection(&CriticalSection);
    return(SQLBindCol(hstmt, col, type, colInfo[col]->data,
        len, &retLen));
}
				

To:

  RETCODE CODBCCursor::bindColumn(UWORD& col, char *columnName,
      SDWORD len, SWORD type)
  {
      EnterCriticalSection(&CriticalSection);
      col = assignColumn(columnName, len);
      colInfo[col]->type = type;
      LeaveCriticalSection(&CriticalSection);
      return(SQLBindCol(hstmt, col, type, colInfo[col]->data,
          len, &colInfo[col]->retLen));
  }
				

Page 48: Listing 2-1 Code Corrections

On page 48 and 49, the code in Listing 2-1 should be corrected to read as follows.

#include <stdio.h>
#include <conio.h>
#include <windows.h>
#include <process.h>

CRITICAL_SECTION csExit;
BOOL exitNow=FALSE;
HANDLE hMutex;

unsigned __stdcall SecondThreadFunc(void* pArguments);
int main(int argc, char* argv[]);

unsigned __stdcall SecondThreadFunc(void* pArguments) 
{ 
    int threadNum;
    threadNum=*((int *)pArguments);
    printf("In thread %d...\n",threadNum);
    
    while (TRUE)
    {
        DWORD rv = WaitForSingleObject(hMutex,INFINITE);

        // Check for an error
        if (rv == WAIT_FAILED)
        {
            LPVOID lpMsgBuf;
            
            FormatMessage( 
                FORMAT_MESSAGE_ALLOCATE_BUFFER | 
                FORMAT_MESSAGE_FROM_SYSTEM  | 
                FORMAT_MESSAGE_IGNORE_INSERTS,
                NULL,
                GetLastError(),
                MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
                (LPTSTR) &lpMsgBuf,
                0,
                NULL);

            MessageBox( NULL, (LPCTSTR)lpMsgBuf, "Error", MB_OK | MB_ICONINFORMATION );

            LocalFree( lpMsgBuf );
        }

        Sleep(1000*threadNum);
        EnterCriticalSection(&csExit);
        if (exitNow) 
        {
            printf("\nThread %d GONE!",threadNum);
        
            LeaveCriticalSection(&csExit);
            ReleaseMutex(hMutex);
 
            _endthreadex(0);
        }
        LeaveCriticalSection(&csExit);
        ReleaseMutex(hMutex);
        printf("\nThread %d still going",threadNum);
    }
    return 0;
}

int main(int argc, char* argv[])
{
    int loop;
    int threadCount[5];
    unsigned threadID[5];
    HANDLE   threadHandle[5];

    // Got to reate the Mutex first. 
    hMutex = CreateMutex(0, FALSE, 0); 

    InitializeCriticalSection(&csExit);
    __try
    {
        for (loop=0 ; loop<5 ; loop++)
        {
            threadCount[loop] = loop+1;

            threadHandle[loop] = 
                (HANDLE) _beginthreadex(
                    NULL,
                    0,
                    &SecondThreadFunc,
                    &threadCount[loop],
                    0,
                    &threadID[loop]);
        }

        getch();

        EnterCriticalSection(&csExit);
        exitNow=TRUE;
        LeaveCriticalSection(&csExit);
    }
    __finally
    {

        // Make sure the threads have exited...
        WaitForMultipleObjects(5, threadHandle, TRUE, INFINITE);

        DeleteCriticalSection(&csExit);
    }
    
    CloseHandle(hMutex);

    printf("\nProgram completed");

    return 0;
}
				

Page 276: Figure 8-3 Is Incorrect

On page 276, Figure 8-2 and Figure 8-3 are exactly the same. Figure 8-3 is incorrect and will not match your computer screen.

Chapter 9: <ES> Tags Should Be <BR>

In several places in Chapter 9, the code samples include an <ES> tag. This tag should be changed to <BR>.

The affected code samples are:

• Page 330 line 11
• Page 334 line 10
• Page 338 line 26
• Page 341 line 18
• Page 342 line 12
• Page 343 lines 36, 41, 43
• Page 344 lines 5, 6
• Page 346 lines 23, 30
• Page 347 line 23

The same correction must be made in the text on page 334, paragraph 1, sentences 3 & 4.

Microsoft Press is committed to providing informative and accurate books. All comments and corrections listed above are ready for inclusion in future printings of this book. If you have a later printing of this book, it may already contain most or all of the above corrections.