show Windows API error text corresponding to number retured by GetLastError. source: http://msdn.microsoft.com/en-us/library/windows/desktop/bb540534(v=vs.85).aspx

GetLastError.cpp

void DisplayError(LPTSTR lpszFunction) 
// Routine Description:
// Retrieve and output the system error message for the last-error code
{ 
    LPVOID lpMsgBuf;
    LPVOID lpDisplayBuf;
    DWORD dw = GetLastError(); 

    FormatMessage(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | 
        FORMAT_MESSAGE_FROM_SYSTEM |
        FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        dw,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        (LPTSTR) &lpMsgBuf,
        0, 
        NULL );

    lpDisplayBuf = 
        (LPVOID)LocalAlloc( LMEM_ZEROINIT, 
                            ( lstrlen((LPCTSTR)lpMsgBuf)
                              + lstrlen((LPCTSTR)lpszFunction)
                              + 40) // account for format string
                            * sizeof(TCHAR) );
    
    if (FAILED( StringCchPrintf((LPTSTR)lpDisplayBuf, 
                     LocalSize(lpDisplayBuf) / sizeof(TCHAR),
                     TEXT("%s failed with error code %d as follows:\n%s"), 
                     lpszFunction, 
                     dw, 
                     lpMsgBuf)))
    {
        printf("FATAL ERROR: Unable to output error code.\n");
    }
    
    _tprintf(TEXT("ERROR: %s\n"), (LPCTSTR)lpDisplayBuf);

    LocalFree(lpMsgBuf);
    LocalFree(lpDisplayBuf);