为什么找不到CWinApp成员变量m_pszAppName的定义

class CWinApp : public CWinThread
{
    DECLARE_DYNAMIC(CWinApp)
public:

// Constructor
    explicit CWinApp(LPCTSTR lpszAppName = NULL);     // app name defaults to EXE name

// Attributes
    // Startup args (do not change)

    // This module's hInstance.
    HINSTANCE m_hInstance;

    // Pointer to the command-line.
    LPTSTR m_lpCmdLine;

    // Initial state of the application's window; normally,
    // this is an argument to ShowWindow().
    int m_nCmdShow;

    // Running args (can be changed in InitInstance)

    // Human-redable name of the application. Normally set in
    // constructor or retreived from AFX_IDS_APP_TITLE.
    LPCTSTR m_pszAppName;、、---------------------------------就在这里定义的