ShowWindow

The ShowWindow function sets the specified window's show state.

BOOL ShowWindow(
  HWND hWnd,     // handle to window
  int nCmdShow   // show state of window
);
 

Parameters

hWnd

Handle to the window.

nCmdShow

Specifies how the window is to be shown. This parameter is ignored the first time an application calls ShowWindow, if the program that launched the application provides a STARTUPINFO structure. Otherwise, the first time ShowWindow is called, the value should be the value obtained by the WinMain function in its nCmdShow parameter. In subsequent calls, this parameter can be one of the following values:

Value	Meaning
SW_FORCEMINIMIZE	Windows NT 5.0 and later: Minimizes a window, even if the thread that owns the window is hung. This flag should only be used when minimizing windows from a different thread.
SW_HIDE	Hides the window and activates another window.
SW_MAXIMIZE	Maximizes the specified window.
SW_MINIMIZE	Minimizes the specified window and activates the next top-level window in the Z order.
SW_RESTORE	Activates and displays the window. If the window is minimized or maximized, the system restores it to its original size and position. An application should specify this flag when restoring a minimized window.
SW_SHOW	Activates the window and displays it in its current size and position.
SW_SHOWDEFAULT	Sets the show state based on the SW_ flag specified in the STARTUPINFO structure passed to the CreateProcess function by the program that started the application.
SW_SHOWMAXIMIZED	Activates the window and displays it as a maximized window.
SW_SHOWMINIMIZED	Activates the window and displays it as a minimized window.
SW_SHOWMINNOACTIVE	Displays the window as a minimized window. The active window remains active.
SW_SHOWNA	Displays the window in its current state. The active window remains active.
SW_SHOWNOACTIVATE	Displays a window in its most recent size and position. The active window remains active.
SW_SHOWNORMAL	Activates and displays a window. If the window is minimized or maximized, the system restores it to its original size and position. An application should specify this flag when displaying the window for the first time.

Return Values

If the window was previously visible, the return value is nonzero.

If the window was previously hidden, the return value is zero.

Remarks

The first time an application calls ShowWindow, it should use the WinMain function's nCmdShow parameter as its nCmdShow parameter. Subsequent calls to ShowWindow must use one of the values in the given list, instead of the one specified by the WinMain function's nCmdShow parameter.

As noted in the discussion of the nCmdShow parameter, the nCmdShow value is ignored in the first call to ShowWindow if the program that launched the application specifies startup information in the STARTUPINFO structure. In this case, ShowWindow uses the information specified in the STARTUPINFO structure to show the window. On subsequent calls, the application must call ShowWindow with nCmdShow set to SW_SHOWDEFAULT to use the startup information provided by the program that launched the application. This behavior is designed for the following situations:

• Applications create their main window by calling CreateWindow with the WS_VISIBLE flag set.
• Applications create their main window by calling CreateWindow with the WS_VISIBLE flag cleared, and later call ShowWindow with the SW_SHOW flag set to make it visible.

Windows CE: The nCmdShow parameter does not support the following values:

SW_MAXIMIZE

SW_MINIMIZE

SW_RESTORE

SW_SHOWDEFAULT

SW_SHOWMAXIMIZED

SW_SHOWMINIMIZED

SW_SHOWMINNOACTIVE

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Requires version 1.0 or later.
  Header: Declared in winuser.h.
  Import Library: Use user32.lib.

See Also

Windows Overview, Window Functions, CreateProcess, CreateWindow, ShowOwnedPopups, STARTUPINFO, WinMain