FlashWindow

The FlashWindow function flashes the specified window one time. It does not change the active state of the window.

To flash the window a specified number of times, use the FlashWindowEx function.

BOOL FlashWindow(
  HWND hWnd,     // handle to window
  BOOL bInvert   // flash status
);

Parameters

hWnd

[in] Handle to the window to be flashed. The window can be either open or minimized.

bInvert

[in] Specifies whether the window is to be flashed or returned to its original state. The window is flashed from one state to the other if this parameter is TRUE. If it is FALSE, the window is returned to its original state (either active or inactive). When an application is minimized, if this parameter is TRUE, the taskbar window button flashes active/inactive. If it is FALSE, the taskbar window button flashes inactive, meaning that it does not change colors. It flashes, as if it were being redraw, but it does not provide the visual invert clue to the user.

Return Values

The return value specifies the window's state before the call to the FlashWindow function. If the window caption was drawn as active before the call, the return value is nonzero. Otherwise, the return value is zero.

Remarks

Flashing a window means changing the appearance of its caption bar as if the window were changing from inactive to active status, or vice versa. (An inactive caption bar changes to an active caption bar; an active caption bar changes to an inactive caption bar.)

Typically, a window is flashed to inform the user that the window requires attention but that it does not currently have the keyboard focus.

The FlashWindow function flashes the window only once; for repeated flashing, the application should create a system timer.

Requirements

  Windows NT/2000: Requires Windows NT 3.1 or later.
  Windows 95/98: Requires Windows 95 or later.
  Header: Declared in Winuser.h; include Windows.h.
  Library: Use User32.lib.

See Also

Error Handling Overview, Error Handling Functions