当系统时间被手工改变，系统会发出什么消息？

[ilbj]

当系统时间被人工改变，系统会发出什么消息？

[bcpl]

WM_TIMECHANGE

[思危]

WM_TIMECHANGE
An application sends the WM_TIMECHANGE message whenever it updates the system time.

To send this message, call the SendMessage function with the following parameters.

SendMessage(
(HWND) hWnd, // handle to destination window
WM_TIMECHANGE, // message to send
(WPARAM) wParam, // not used; must be zero
(LPARAM) lParam // not used; must be zero
);
Parameters
This message has no parameters.

Return Values
An application should return zero if it processes this message.

Remarks
To send this message to all top-level windows, an application can use the SendMessage function with the hWnd parameter set to HWND_TOPMOST.

Windows 2000/XP: An application should not broadcast this message, because the system will broadcast this message when the application changes the system time.

Windows NT 4.0 and earlier: An application should send this message to all top-level windows after changing the system time.

Windows 95/98/Me: An application should send this message to all top-level windows after changing the system time.

[fengqinggao]

如果你要捕捉该消息的话，这个函数估计有用（从MSDN拷贝而来）：
CWnd::OnTimeChange
afx_msg void OnTimeChange( );

Remarks

The framework calls this member function after the system time is changed.

Have any application that changes the system time send this message to all top-level windows. To send the WM_TIMECHANGE message to all top-level windows, an application can use theSendMessage Windows function with its hwnd parameter set to HWND_BROADCAST.