Retrieves or sets the value of one of the system-wide parameters. This function can also update the user profile while setting a parameter.

Syntax

BOOL WINAPI SystemParametersInfo(
  __in     UINT uiAction,
  __in     UINT uiParam,
  __inout  PVOID pvParam,
  __in     UINT fWinIni
);

Parameters

uiAction [in]

The system-wide parameter to be retrieved or set. This parameter can be one of the following values. They are organized in tables of related parameters.

The following are the accessibility parameters.

Accessibility parameter	Meaning
SPI_GETACCESSTIMEOUT	Retrieves information about the time-out period associated with the accessibility features. The pvParam parameter must point to an ACCESSTIMEOUT structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(ACCESSTIMEOUT).
SPI_GETAUDIODESCRIPTION	Determines whether audio descriptions are enabled or disabled. The pvParam parameter is a pointer to an AUDIODESCRIPTION structure. Set the cbSize member of this structure and the uiParam parameter to sizeof(AUDIODESCRIPTION). While it is possible for users who have visual impairments to hear the audio in video content, there is a lot of action in video that does not have corresponding audio. Specific audio description of what is happening in a video helps these users understand the content better. This flag enables you to determine whether audio descriptions have been enabled and in which language. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_GETCLIENTAREAANIMATION	Determines whether animations are enabled or disabled. The pvParam parameter must point to a BOOL variable that receives TRUE if animations are disabled, or FALSE otherwise. Display features such as flashing, blinking, flickering, and moving content can cause seizures in users with photo-sensitive epilepsy. This flag enables you to determine whether such animations have been disabled in the client area. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_GETDISABLEOVERLAPPEDCONTENT	Determines whether overlapped content is enabled or disabled. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled, or FALSE otherwise. Display features such as background images, textured backgrounds, water marks on documents, alpha-blending, and transparency can reduce the contrast between the foreground and background, making it harder for users with low vision to see objects on the screen. This flag enables you to determine whether such overlapped content has been disabled. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_GETFILTERKEYS	Retrieves information about the FilterKeys accessibility feature. The pvParam parameter must point to a FILTERKEYS structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(FILTERKEYS).
SPI_GETFOCUSBORDERHEIGHT	Retrieves the height, in pixels, of the top and bottom edges of the focus rectangle drawn with DrawFocusRect. The pvParam parameter must point to a UINT value. Windows 2000:  This parameter is not supported.
SPI_GETFOCUSBORDERWIDTH	Retrieves the width, in pixels, of the left and right edges of the focus rectangle drawn with DrawFocusRect. The pvParam parameter must point to a UINT. Windows 2000:  This parameter is not supported.
SPI_GETHIGHCONTRAST	Retrieves information about the HighContrast accessibility feature. The pvParam parameter must point to a HIGHCONTRAST structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(HIGHCONTRAST). For a general discussion, see Remarks.
SPI_GETMESSAGEDURATION	Retrieves the time that notification pop-ups should be displayed, in seconds. The pvParam parameter must point to a ULONG that receives the message duration. Users with visual impairments or cognitive conditions such as ADHD and dyslexia might need a longer time to read the text in notification messages. This flag enables you to retrieve the message duration. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_GETMOUSECLICKLOCK	Retrieves the state of the Mouse ClickLock feature. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled, or FALSE otherwise. For more information, see About Mouse Input. Windows 2000:  This parameter is not supported.
SPI_GETMOUSECLICKLOCKTIME	Retrieves the time delay before the primary mouse button is locked. The pvParam parameter must point to DWORD that receives the time delay, in milliseconds. This is only enabled if SPI_SETMOUSECLICKLOCK is set to TRUE. For more information, see About Mouse Input. Windows 2000:  This parameter is not supported.
SPI_GETMOUSEKEYS	Retrieves information about the MouseKeys accessibility feature. The pvParam parameter must point to a MOUSEKEYS structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(MOUSEKEYS).
SPI_GETMOUSESONAR	Retrieves the state of the Mouse Sonar feature. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled or FALSE otherwise. For more information, see About Mouse Input. Windows 2000:  This parameter is not supported.
SPI_GETMOUSEVANISH	Retrieves the state of the Mouse Vanish feature. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled or FALSE otherwise. For more information, see About Mouse Input. Windows 2000:  This parameter is not supported.
SPI_GETSCREENREADER	Determines whether a screen reviewer utility is running. A screen reviewer utility directs textual information to an output device, such as a speech synthesizer or Braille display. When this flag is set, an application should provide textual information in situations where it would otherwise present the information graphically. The pvParam parameter is a pointer to a BOOL variable that receives TRUE if a screen reviewer utility is running, or FALSE otherwise.
SPI_GETSERIALKEYS	This parameter is not supported. Windows Server 2003 and Windows XP/2000:  The user should control this setting through the Control Panel.
SPI_GETSHOWSOUNDS	Determines whether the Show Sounds accessibility flag is on or off. If it is on, the user requires an application to present information visually in situations where it would otherwise present the information only in audible form. The pvParam parameter must point to a BOOL variable that receives TRUE if the feature is on, or FALSE if it is off. Using this value is equivalent to calling GetSystemMetrics with SM_SHOWSOUNDS. That is the recommended call.
SPI_GETSOUNDSENTRY	Retrieves information about the SoundSentry accessibility feature. The pvParam parameter must point to a SOUNDSENTRY structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(SOUNDSENTRY).
SPI_GETSTICKYKEYS	Retrieves information about the StickyKeys accessibility feature. The pvParam parameter must point to a STICKYKEYS structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(STICKYKEYS).
SPI_GETTOGGLEKEYS	Retrieves information about the ToggleKeys accessibility feature. The pvParam parameter must point to a TOGGLEKEYS structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(TOGGLEKEYS).
SPI_SETACCESSTIMEOUT	Sets the time-out period associated with the accessibility features. The pvParam parameter must point to an ACCESSTIMEOUT structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(ACCESSTIMEOUT).
SPI_SETAUDIODESCRIPTION	Turns the audio descriptions feature on or off. The pvParam parameter is a pointer to an AUDIODESCRIPTION structure. While it is possible for users who are visually impaired to hear the audio in video content, there is a lot of action in video that does not have corresponding audio. Specific audio description of what is happening in a video helps these users understand the content better. This flag enables you to enable or disable audio descriptions in the languages they are provided in. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_SETCLIENTAREAANIMATION	Turns client area animations on or off. The pvParam parameter is a BOOL variable. Set pvParam to TRUE to disable animations and other transient effects in the client area, or FALSE to enable them. Display features such as flashing, blinking, flickering, and moving content can cause seizures in users with photo-sensitive epilepsy. This flag enables you to enable or disable all such animations. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_SETDISABLEOVERLAPPEDCONTENT	Turns overlapped content (such as background images and watermarks) on or off. The pvParam parameter is a BOOL variable. Set pvParam to TRUE to disable overlapped content, or FALSE to enable overlapped content. Display features such as background images, textured backgrounds, water marks on documents, alpha-blending, and transparency can reduce the contrast between the foreground and background, making it harder for users with low vision to see objects on the screen. This flag enables you to enable or disable all such overlapped content. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_SETFILTERKEYS	Sets the parameters of the FilterKeys accessibility feature. The pvParam parameter must point to a FILTERKEYS structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(FILTERKEYS).
SPI_SETFOCUSBORDERHEIGHT	Sets the height of the top and bottom edges of the focus rectangle drawn with DrawFocusRect to the value of the pvParam parameter. Windows 2000:  This parameter is not supported.
SPI_SETFOCUSBORDERWIDTH	Sets the height of the left and right edges of the focus rectangle drawn with DrawFocusRect to the value of the pvParam parameter. Windows 2000:  This parameter is not supported.
SPI_SETHIGHCONTRAST	Sets the parameters of the HighContrast accessibility feature. The pvParam parameter must point to a HIGHCONTRAST structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(HIGHCONTRAST).
SPI_SETMESSAGEDURATION	Sets the time that notification pop-ups should be displayed, in seconds. The pvParam parameter must point to a ULONG that specifies the message duration. Users with visual impairments or cognitive conditions such as ADHD and dyslexia might need a longer time to read the text in notification messages. This flag enables you to set the message duration. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_SETMOUSECLICKLOCK	Turns the Mouse ClickLock accessibility feature on or off. This feature temporarily locks down the primary mouse button when that button is clicked and held down for the time specified by SPI_SETMOUSECLICKLOCKTIME. The uiParam parameter specifies TRUE for on, or FALSE for off. The default is off. For more information, see Remarks and About Mouse Input. Windows 2000:  This parameter is not supported.
SPI_SETMOUSECLICKLOCKTIME	Adjusts the time delay before the primary mouse button is locked. The uiParam parameter should be set to 0. The pvParam parameter points to a DWORD that specifies the time delay in milliseconds. For example, specify 1000 for a 1 second delay. The default is 1200. For more information, see About Mouse Input. Windows 2000:  This parameter is not supported.
SPI_SETMOUSEKEYS	Sets the parameters of the MouseKeys accessibility feature. The pvParam parameter must point to a MOUSEKEYS structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(MOUSEKEYS).
SPI_SETMOUSESONAR	Turns the Sonar accessibility feature on or off. This feature briefly shows several concentric circles around the mouse pointer when the user presses and releases the CTRL key. The pvParam parameter specifies TRUE for on and FALSE for off. The default is off. For more information, see About Mouse Input. Windows 2000:  This parameter is not supported.
SPI_SETMOUSEVANISH	Turns the Vanish feature on or off. This feature hides the mouse pointer when the user types; the pointer reappears when the user moves the mouse. The pvParam parameter specifies TRUE for on and FALSE for off. The default is off. For more information, see About Mouse Input. Windows 2000:  This parameter is not supported.
SPI_SETSCREENREADER	Determines whether a screen review utility is running. The uiParam parameter specifies TRUE for on, or FALSE for off.
SPI_SETSERIALKEYS	This parameter is not supported. Windows Server 2003 and Windows XP/2000:  The user should control this setting through the Control Panel.
SPI_SETSHOWSOUNDS	Turns the ShowSounds accessibility feature on or off. The uiParam parameter specifies TRUE for on, or FALSE for off.
SPI_SETSOUNDSENTRY	Sets the parameters of the SoundSentry accessibility feature. The pvParam parameter must point to a SOUNDSENTRY structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(SOUNDSENTRY).
SPI_SETSTICKYKEYS	Sets the parameters of the StickyKeys accessibility feature. The pvParam parameter must point to a STICKYKEYS structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(STICKYKEYS).
SPI_SETTOGGLEKEYS	Sets the parameters of the ToggleKeys accessibility feature. The pvParam parameter must point to a TOGGLEKEYS structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(TOGGLEKEYS).

The following are the desktop parameters.

Desktop parameter	Meaning
SPI_GETCLEARTYPE	Determines whether ClearType is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE if ClearType is enabled, or FALSE otherwise. ClearType is a software technology that improves the readability of text on liquid crystal display (LCD) monitors. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_GETDESKWALLPAPER	Retrieves the full path of the bitmap file for the desktop wallpaper. The pvParam parameter must point to a buffer to receive the NULL-terminated path string. Set the uiParam parameter to the size, in characters, of the pvParam buffer. The returned string will not exceed MAX_PATH characters. If there is no desktop wallpaper, the returned string is empty.
SPI_GETDROPSHADOW	Determines whether the drop shadow effect is enabled. The pvParam parameter must point to a BOOL variable that returns TRUE if enabled or FALSE if disabled. Windows 2000:  This parameter is not supported.
SPI_GETFLATMENU	Determines whether native User menus have flat menu appearance. The pvParam parameter must point to a BOOL variable that returns TRUE if the flat menu appearance is set, or FALSE otherwise. Windows 2000:  This parameter is not supported.
SPI_GETFONTSMOOTHING	Determines whether the font smoothing feature is enabled. This feature uses font antialiasing to make font curves appear smoother by painting pixels at different gray levels. The pvParam parameter must point to a BOOL variable that receives TRUE if the feature is enabled, or FALSE if it is not.
SPI_GETFONTSMOOTHINGCONTRAST	Retrieves a contrast value that is used in ClearType smoothing. The pvParam parameter must point to a UINT that receives the information. Valid contrast values are from 1000 to 2200. The default value is 1400. Windows 2000:  This parameter is not supported.
SPI_GETFONTSMOOTHINGORIENTATION	Retrieves the font smoothing orientation. The pvParam parameter must point to a UINT that receives the information. The possible values are FE_FONTSMOOTHINGORIENTATIONBGR (blue-green-red) and FE_FONTSMOOTHINGORIENTATIONRGB (red-green-blue). Windows XP/2000:  This parameter is not supported until Windows XP SP2.
SPI_GETFONTSMOOTHINGTYPE	Retrieves the type of font smoothing. The pvParam parameter must point to a UINT that receives the information. The possible values are FE_FONTSMOOTHINGSTANDARD and FE_FONTSMOOTHINGCLEARTYPE. Windows 2000:  This parameter is not supported.
SPI_GETWORKAREA	Retrieves the size of the work area on the primary display monitor. The work area is the portion of the screen not obscured by the system taskbar or by application desktop toolbars. The pvParam parameter must point to a RECT structure that receives the coordinates of the work area, expressed in virtual screen coordinates. To get the work area of a monitor other than the primary display monitor, call the GetMonitorInfo function.
SPI_SETCLEARTYPE	Turns ClearType on or off. The pvParam parameter is a BOOL variable. Set pvParam to TRUE to enable ClearType, or FALSE to disable it. ClearType is a software technology that improves the readability of text on LCD monitors. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_SETCURSORS	Reloads the system cursors. Set the uiParam parameter to zero and the pvParam parameter to NULL.
SPI_SETDESKPATTERN	Sets the current desktop pattern by causing Windows to read the Pattern= setting from the WIN.INI file.
SPI_SETDESKWALLPAPER	Sets the desktop wallpaper. The value of the pvParam parameter determines the new wallpaper. To specify a wallpaper bitmap, set pvParam to point to a NULL-terminated string containing the full path to the bitmap file. Setting pvParam to "" removes the wallpaper. Setting pvParam to SETWALLPAPER_DEFAULT or NULL reverts to the default wallpaper. The pvParam parameter can specify a .jpg file. Windows Server 2003 and Windows XP/2000:  The pvParam parameter cannot specify a .jpg file.
SPI_SETDROPSHADOW	Enables or disables the drop shadow effect. Set pvParam to TRUE to enable the drop shadow effect or FALSE to disable it. You must also have CS_DROPSHADOW in the window class style. Windows 2000:  This parameter is not supported.
SPI_SETFLATMENU	Enables or disables flat menu appearance for native User menus. Set pvParam to TRUE to enable flat menu appearance or FALSE to disable it. When enabled, the menu bar uses COLOR_MENUBAR for the menubar background, COLOR_MENU for the menu-popup background, COLOR_MENUHILIGHT for the fill of the current menu selection, and COLOR_HILIGHT for the outline of the current menu selection. If disabled, menus are drawn using the same metrics and colors as in Windows 2000. Windows 2000:  This parameter is not supported.
SPI_SETFONTSMOOTHING	Enables or disables the font smoothing feature, which uses font antialiasing to make font curves appear smoother by painting pixels at different gray levels. To enable the feature, set the uiParam parameter to TRUE. To disable the feature, set uiParam to FALSE.
SPI_SETFONTSMOOTHINGCONTRAST	Sets the contrast value used in ClearType smoothing. The pvParam parameter is the contrast value. Valid contrast values are from 1000 to 2200. The default value is 1400. SPI_SETFONTSMOOTHINGTYPE must also be set to FE_FONTSMOOTHINGCLEARTYPE. Windows 2000:  This parameter is not supported.
SPI_SETFONTSMOOTHINGORIENTATION	Sets the font smoothing orientation. The pvParam parameter is either FE_FONTSMOOTHINGORIENTATIONBGR (blue-green-red) or FE_FONTSMOOTHINGORIENTATIONRGB (red-green-blue). Windows XP/2000:  This parameter is not supported until Windows XP SP2.
SPI_SETFONTSMOOTHINGTYPE	Sets the font smoothing type. The pvParam parameter is either FE_FONTSMOOTHINGSTANDARD, if standard anti-aliasing is used, or FE_FONTSMOOTHINGCLEARTYPE, if ClearType is used. The default is FE_FONTSMOOTHINGSTANDARD. SPI_SETFONTSMOOTHING must also be set. Windows 2000:  This parameter is not supported.
SPI_SETWORKAREA	Sets the size of the work area. The work area is the portion of the screen not obscured by the system taskbar or by application desktop toolbars. The pvParam parameter is a pointer to a RECT structure that specifies the new work area rectangle, expressed in virtual screen coordinates. In a system with multiple display monitors, the function sets the work area of the monitor that contains the specified rectangle.

The following are the icon parameters.

Icon parameter	Meaning
SPI_GETICONMETRICS	Retrieves the metrics associated with icons. The pvParam parameter must point to an ICONMETRICS structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(ICONMETRICS).
SPI_GETICONTITLELOGFONT	Retrieves the logical font information for the current icon-title font. The uiParam parameter specifies the size of a LOGFONT structure, and the pvParam parameter must point to the LOGFONT structure to fill in.
SPI_GETICONTITLEWRAP	Determines whether icon-title wrapping is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled, or FALSE otherwise.
SPI_ICONHORIZONTALSPACING	Sets or retrieves the width, in pixels, of an icon cell. The system uses this rectangle to arrange icons in large icon view. To set this value, set uiParam to the new value and set pvParam to NULL. You cannot set this value to less than SM_CXICON. To retrieve this value, pvParam must point to an integer that receives the current value.
SPI_ICONVERTICALSPACING	Sets or retrieves the height, in pixels, of an icon cell. To set this value, set uiParam to the new value and set pvParam to NULL. You cannot set this value to less than SM_CYICON. To retrieve this value, pvParam must point to an integer that receives the current value.
SPI_SETICONMETRICS	Sets the metrics associated with icons. The pvParam parameter must point to an ICONMETRICS structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(ICONMETRICS).
SPI_SETICONS	Reloads the system icons. Set the uiParam parameter to zero and the pvParam parameter to NULL.
SPI_SETICONTITLELOGFONT	Sets the font that is used for icon titles. The uiParam parameter specifies the size of a LOGFONT structure, and the pvParam parameter must point to a LOGFONT structure.
SPI_SETICONTITLEWRAP	Turns icon-title wrapping on or off. The uiParam parameter specifies TRUE for on, or FALSE for off.

The following are the input parameters. They include parameters related to the keyboard, mouse, input language, and the warning beeper.

Input parameter	Meaning
SPI_GETBEEP	Determines whether the warning beeper is on. The pvParam parameter must point to a BOOL variable that receives TRUE if the beeper is on, or FALSE if it is off.
SPI_GETBLOCKSENDINPUTRESETS	Retrieves a BOOL indicating whether an application can reset the screensaver's timer by calling the SendInput function to simulate keyboard or mouse input. The pvParam parameter must point to a BOOL variable that receives TRUE if the simulated input will be blocked, or FALSE otherwise.
SPI_GETDEFAULTINPUTLANG	Retrieves the input locale identifier for the system default input language. The pvParam parameter must point to an HKL variable that receives this value. For more information, see Languages, Locales, and Keyboard Layouts.
SPI_GETKEYBOARDCUES	Determines whether menu access keys are always underlined. The pvParam parameter must point to a BOOL variable that receives TRUE if menu access keys are always underlined, and FALSE if they are underlined only when the menu is activated by the keyboard.
SPI_GETKEYBOARDDELAY	Retrieves the keyboard repeat-delay setting, which is a value in the range from 0 (approximately 250 ms delay) through 3 (approximately 1 second delay). The actual delay associated with each value may vary depending on the hardware. The pvParam parameter must point to an integer variable that receives the setting.
SPI_GETKEYBOARDPREF	Determines whether the user relies on the keyboard instead of the mouse, and wants applications to display keyboard interfaces that would otherwise be hidden. The pvParam parameter must point to a BOOL variable that receives TRUE if the user relies on the keyboard; or FALSE otherwise.
SPI_GETKEYBOARDSPEED	Retrieves the keyboard repeat-speed setting, which is a value in the range from 0 (approximately 2.5 repetitions per second) through 31 (approximately 30 repetitions per second). The actual repeat rates are hardware-dependent and may vary from a linear scale by as much as 20%. The pvParam parameter must point to a DWORD variable that receives the setting.
SPI_GETMOUSE	Retrieves the two mouse threshold values and the mouse acceleration. The pvParam parameter must point to an array of three integers that receives these values. See mouse_event for further information.
SPI_GETMOUSEHOVERHEIGHT	Retrieves the height, in pixels, of the rectangle within which the mouse pointer has to stay for TrackMouseEvent to generate a WM_MOUSEHOVER message. The pvParam parameter must point to a UINT variable that receives the height.
SPI_GETMOUSEHOVERTIME	Retrieves the time, in milliseconds, that the mouse pointer has to stay in the hover rectangle for TrackMouseEvent to generate a WM_MOUSEHOVER message. The pvParam parameter must point to a UINT variable that receives the time.
SPI_GETMOUSEHOVERWIDTH	Retrieves the width, in pixels, of the rectangle within which the mouse pointer has to stay for TrackMouseEvent to generate a WM_MOUSEHOVER message. The pvParam parameter must point to a UINT variable that receives the width.
SPI_GETMOUSESPEED	Retrieves the current mouse speed. The mouse speed determines how far the pointer will move based on the distance the mouse moves. The pvParam parameter must point to an integer that receives a value which ranges between 1 (slowest) and 20 (fastest). A value of 10 is the default. The value can be set by an end-user using the mouse control panel application or by an application using SPI_SETMOUSESPEED.
SPI_GETMOUSETRAILS	Determines whether the Mouse Trails feature is enabled. This feature improves the visibility of mouse cursor movements by briefly showing a trail of cursors and quickly erasing them. The pvParam parameter must point to an integer variable that receives a value. If the value is zero or 1, the feature is disabled. If the value is greater than 1, the feature is enabled and the value indicates the number of cursors drawn in the trail. The uiParam parameter is not used. Windows 2000:  This parameter is not supported.
SPI_GETSNAPTODEFBUTTON	Determines whether the snap-to-default-button feature is enabled. If enabled, the mouse cursor automatically moves to the default button, such as OK or Apply, of a dialog box. The pvParam parameter must point to a BOOL variable that receives TRUE if the feature is on, or FALSE if it is off.
SPI_GETWHEELSCROLLCHARS	Retrieves the number of characters to scroll when the horizontal mouse wheel is moved. The pvParam parameter must point to a UINT variable that receives the number of lines. The default value is 3.
SPI_GETWHEELSCROLLLINES	Retrieves the number of lines to scroll when the vertical mouse wheel is moved. The pvParam parameter must point to a UINT variable that receives the number of lines. The default value is 3.
SPI_SETBEEP	Turns the warning beeper on or off. The uiParam parameter specifies TRUE for on, or FALSE for off.
SPI_SETBLOCKSENDINPUTRESETS	Determines whether an application can reset the screensaver's timer by calling the SendInput function to simulate keyboard or mouse input. The uiParam parameter specifies TRUE if the screensaver will not be deactivated by simulated input, or FALSE if the screensaver will be deactivated by simulated input.
SPI_SETDEFAULTINPUTLANG	Sets the default input language for the system shell and applications. The specified language must be displayable using the current system character set. The pvParam parameter must point to an HKL variable that contains the input locale identifier for the default language. For more information, see Languages, Locales, and Keyboard Layouts.
SPI_SETDOUBLECLICKTIME	Sets the double-click time for the mouse to the value of the uiParam parameter. The double-click time is the maximum number of milliseconds that can occur between the first and second clicks of a double-click. You can also call the SetDoubleClickTime function to set the double-click time. To get the current double-click time, call the GetDoubleClickTime function.
SPI_SETDOUBLECLKHEIGHT	Sets the height of the double-click rectangle to the value of the uiParam parameter. The double-click rectangle is the rectangle within which the second click of a double-click must fall for it to be registered as a double-click. To retrieve the height of the double-click rectangle, call GetSystemMetrics with the SM_CYDOUBLECLK flag.
SPI_SETDOUBLECLKWIDTH	Sets the width of the double-click rectangle to the value of the uiParam parameter. The double-click rectangle is the rectangle within which the second click of a double-click must fall for it to be registered as a double-click. To retrieve the width of the double-click rectangle, call GetSystemMetrics with the SM_CXDOUBLECLK flag.
SPI_SETKEYBOARDCUES	Sets the underlining of menu access key letters. The pvParam parameter is a BOOL variable. Set pvParam to TRUE to always underline menu access keys, or FALSE to underline menu access keys only when the menu is activated from the keyboard.
SPI_SETKEYBOARDDELAY	Sets the keyboard repeat-delay setting. The uiParam parameter must specify 0, 1, 2, or 3, where zero sets the shortest delay approximately 250 ms) and 3 sets the longest delay (approximately 1 second). The actual delay associated with each value may vary depending on the hardware.
SPI_SETKEYBOARDPREF	Sets the keyboard preference. The uiParam parameter specifies TRUE if the user relies on the keyboard instead of the mouse, and wants applications to display keyboard interfaces that would otherwise be hidden; uiParam is FALSE otherwise.
SPI_SETKEYBOARDSPEED	Sets the keyboard repeat-speed setting. The uiParam parameter must specify a value in the range from 0 (approximately 2.5 repetitions per second) through 31 (approximately 30 repetitions per second). The actual repeat rates are hardware-dependent and may vary from a linear scale by as much as 20%. If uiParam is greater than 31, the parameter is set to 31.
SPI_SETLANGTOGGLE	Sets the hot key set for switching between input languages. The uiParam and pvParam parameters are not used. The value sets the shortcut keys in the keyboard property sheets by reading the registry again. The registry must be set before this flag is used. the path in the registry is HKEY_CURRENT_USER\Keyboard Layout\Toggle . Valid values are "1" = ALT+SHIFT, "2" = CTRL+SHIFT, and "3" = none.
SPI_SETMOUSE	Sets the two mouse threshold values and the mouse acceleration. The pvParam parameter must point to an array of three integers that specifies these values. See mouse_event for further information.
SPI_SETMOUSEBUTTONSWAP	Swaps or restores the meaning of the left and right mouse buttons. The uiParam parameter specifies TRUE to swap the meanings of the buttons, or FALSE to restore their original meanings. To retrieve the current setting, call GetSystemMetrics with the SM_SWAPBUTTON flag.
SPI_SETMOUSEHOVERHEIGHT	Sets the height, in pixels, of the rectangle within which the mouse pointer has to stay for TrackMouseEvent to generate a WM_MOUSEHOVER message. Set the uiParam parameter to the new height.
SPI_SETMOUSEHOVERTIME	Sets the time, in milliseconds, that the mouse pointer has to stay in the hover rectangle for TrackMouseEvent to generate a WM_MOUSEHOVER message. This is used only if you pass HOVER_DEFAULT in the dwHoverTime parameter in the call to TrackMouseEvent. Set the uiParamparameter to the new time. The time specified should be between USER_TIMER_MAXIMUM and USER_TIMER_MINIMUM. If uiParam is less than USER_TIMER_MINIMUM, the function will use USER_TIMER_MINIMUM. If uiParam is greater than USER_TIMER_MAXIMUM, the function will be USER_TIMER_MAXIMUM. Windows Server 2003 and Windows XP:  The operating system does not enforce the use of USER_TIMER_MAXIMUM and USER_TIMER_MINIMUM until Windows Server 2003 SP1 and Windows XP SP2.
SPI_SETMOUSEHOVERWIDTH	Sets the width, in pixels, of the rectangle within which the mouse pointer has to stay for TrackMouseEvent to generate a WM_MOUSEHOVER message. Set the uiParam parameter to the new width.
SPI_SETMOUSESPEED	Sets the current mouse speed. The pvParam parameter is an integer between 1 (slowest) and 20 (fastest). A value of 10 is the default. This value is typically set using the mouse control panel application.
SPI_SETMOUSETRAILS	Enables or disables the Mouse Trails feature, which improves the visibility of mouse cursor movements by briefly showing a trail of cursors and quickly erasing them. To disable the feature, set the uiParam parameter to zero or 1. To enable the feature, set uiParam to a value greater than 1 to indicate the number of cursors drawn in the trail. Windows 2000:  This parameter is not supported.
SPI_SETSNAPTODEFBUTTON	Enables or disables the snap-to-default-button feature. If enabled, the mouse cursor automatically moves to the default button, such as OK or Apply, of a dialog box. Set the uiParam parameter to TRUE to enable the feature, or FALSE to disable it. Applications should use the ShowWindow function when displaying a dialog box so the dialog manager can position the mouse cursor.
SPI_SETWHEELSCROLLCHARS	Sets the number of characters to scroll when the horizontal mouse wheel is moved. The number of characters is set from the uiParam parameter.
SPI_SETWHEELSCROLLLINES	Sets the number of lines to scroll when the vertical mouse wheel is moved. The number of lines is set from the uiParam parameter. The number of lines is the suggested number of lines to scroll when the mouse wheel is rolled without using modifier keys. If the number is 0, then no scrolling should occur. If the number of lines to scroll is greater than the number of lines viewable, and in particular if it is WHEEL_PAGESCROLL (#defined as UINT_MAX), the scroll operation should be interpreted as clicking once in the page down or page up regions of the scroll bar.

The following are the menu parameters.

Menu parameter	Meaning
SPI_GETMENUDROPALIGNMENT	Determines whether pop-up menus are left-aligned or right-aligned, relative to the corresponding menu-bar item. The pvParam parameter must point to a BOOL variable that receives TRUE if right-aligned, or FALSE otherwise.
SPI_GETMENUFADE	Determines whether menu fade animation is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE when fade animation is enabled and FALSE when it isdisabled. If fade animation is disabled, menus use slide animation. This flag is ignored unless menu animation is enabled, which you can do using the SPI_SETMENUANIMATION flag. For more information, see AnimateWindow.
SPI_GETMENUSHOWDELAY	Retrieves the time, in milliseconds, that the system waits before displaying a shortcut menu when the mouse cursor is over a submenu item. The pvParam parameter must point to a DWORD variable that receives the time of the delay.
SPI_SETMENUDROPALIGNMENT	Sets the alignment value of pop-up menus. The uiParam parameter specifies TRUE for right alignment, or FALSE for left alignment.
SPI_SETMENUFADE	Enables or disables menu fade animation. Set pvParam to TRUE to enable the menu fade effect or FALSE to disable it. If fade animation is disabled, menus use slide animation. he The menu fade effect is possible only if the system has a color depth of more than 256 colors. This flag is ignored unless SPI_MENUANIMATION is also set. For more information, see AnimateWindow.
SPI_SETMENUSHOWDELAY	Sets uiParam to the time, in milliseconds, that the system waits before displaying a shortcut menu when the mouse cursor is over a submenu item.

The display power management parameters are not supported. Instead, to determine the current display power state, an application should register for GUID_MONITOR_POWER_STATE notifications. To determine the current display power down time-out, an application should register for notification of changes to the GUID_VIDEO_POWERDOWN_TIMEOUT power setting. For more information, see Registering for Power Events.

Windows Server 2003 and Windows XP/2000:  To determine the current display power state, use the following power parameters.

Power parameter	Meaning
SPI_GETLOWPOWERACTIVE	Determines whether the low-power phase of screen saving is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled, or FALSE if disabled. This flag is supported for 32-bit applications only. Windows Server 2008 and Windows Vista:  This parameter is not supported.
SPI_GETLOWPOWERTIMEOUT	Retrieves the time-out value for the low-power phase of screen saving. The pvParam parameter must point to an integer variable that receives the value. This flag is supported for 32-bit applications only. Windows Server 2008 and Windows Vista:  This parameter is not supported.
SPI_GETPOWEROFFACTIVE	Determines whether the power-off phase of screen saving is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled, or FALSE if disabled. This flag is supported for 32-bit applications only. Windows Server 2008 and Windows Vista:  This parameter is not supported. When the power-off phase of screen saving is enabled, the GUID_VIDEO_POWERDOWN_TIMEOUT power setting is greater than zero.
SPI_GETPOWEROFFTIMEOUT	Retrieves the time-out value for the power-off phase of screen saving. The pvParam parameter must point to an integer variable that receives the value. This flag is supported for 32-bit applications only. Windows Server 2008 and Windows Vista:  This parameter is not supported. Instead, check the GUID_VIDEO_POWERDOWN_TIMEOUT power setting.
SPI_SETLOWPOWERACTIVE	Activates or deactivates the low-power phase of screen saving. Set uiParam to 1 to activate, or zero to deactivate. The pvParam parameter must be NULL. This flag is supported for 32-bit applications only. Windows Server 2008 and Windows Vista:  This parameter is not supported.
SPI_SETLOWPOWERTIMEOUT	Sets the time-out value, in seconds, for the low-power phase of screen saving. The uiParam parameter specifies the new value. The pvParam parameter must be NULL. This flag is supported for 32-bit applications only. Windows Server 2008 and Windows Vista:  This parameter is not supported.
SPI_SETPOWEROFFACTIVE	Activates or deactivates the power-off phase of screen saving. Set uiParam to 1 to activate, or zero to deactivate. The pvParam parameter must be NULL. This flag is supported for 32-bit applications only. Windows Server 2008 and Windows Vista:  This parameter is not supported. Instead, set the GUID_VIDEO_POWERDOWN_TIMEOUT power setting.
SPI_SETPOWEROFFTIMEOUT	Sets the time-out value, in seconds, for the power-off phase of screen saving. The uiParam parameter specifies the new value. The pvParam parameter must be NULL. This flag is supported for 32-bit applications only. Windows Server 2008 and Windows Vista:  This parameter is not supported. Instead, set the GUID_VIDEO_POWERDOWN_TIMEOUT power setting to a time-out value.

The following are the screen saver parameters.

Screen saver parameter	Meaning
SPI_GETSCREENSAVEACTIVE	Determines whether screen saving is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE if screen saving is enabled, or FALSE otherwise.
SPI_GETSCREENSAVERRUNNING	Determines whether a screen saver is currently running on the window station of the calling process. The pvParam parameter must point to a BOOL variable that receives TRUE if a screen saver is currently running, or FALSE otherwise. Note that only the interactive window station, WinSta0, can have a screen saver running.
SPI_GETSCREENSAVESECURE	Determines whether the screen saver requires a password to display the Windows desktop. The pvParam parameter must point to a BOOL variable that receives TRUE if the screen saver requires a password, or FALSE otherwise. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_GETSCREENSAVETIMEOUT	Retrieves the screen saver time-out value, in seconds. The pvParam parameter must point to an integer variable that receives the value.
SPI_SETSCREENSAVEACTIVE	Sets the state of the screen saver. The uiParam parameter specifies TRUE to activate screen saving, or FALSE to deactivate it.
SPI_SETSCREENSAVESECURE	Sets whether the screen saver requires the user to enter a password to display the Windows desktop. The pvParam parameter is a BOOL variable. Set pvParam to TRUE to require a password, or FALSE to not require a password. Windows Server 2003 and Windows XP/2000:  This parameter is not supported.
SPI_SETSCREENSAVETIMEOUT	Sets the screen saver time-out value to the value of the uiParam parameter. This value is the amount of time, in seconds, that the system must be idle before the screen saver activates.

The following are the UI effects. The SPI_SETUIEFFECTS value is used to enable or disable all UI effects at once. This table contains the complete list of UI effect values.

UI effects parameter	Meaning
SPI_GETCOMBOBOXANIMATION	Determines whether the slide-open effect for combo boxes is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE for enabled, or FALSE for disabled.
SPI_GETCURSORSHADOW	Determines whether the cursor has a shadow around it. The pvParam parameter must point to a BOOL variable that receives TRUE if the shadow is enabled, FALSE if it is disabled. This effect appears only if the system has a color depth of more than 256 colors.
SPI_GETGRADIENTCAPTIONS	Determines whether the gradient effect for window title bars is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE for enabled, or FALSE for disabled. For more information about the gradient effect, see the GetSysColor function.
SPI_GETHOTTRACKING	Determines whether hot tracking of user-interface elements, such as menu names on menu bars, is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE for enabled, or FALSE for disabled. Hot tracking means that when the cursor moves over an item, it is highlighted but not selected. You can query this value to decide whether to use hot tracking in the user interface of your application.
SPI_GETLISTBOXSMOOTHSCROLLING	Determines whether the smooth-scrolling effect for list boxes is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE for enabled, or FALSE for disabled.
SPI_GETMENUANIMATION	Determines whether the menu animation feature is enabled. This master switch must be on to enable menu animation effects. The pvParam parameter must point to a BOOL variable that receives TRUE if animation is enabled and FALSE if it is disabled. If animation is enabled, SPI_GETMENUFADE indicates whether menus use fade or slide animation.
SPI_GETMENUUNDERLINES	Same as SPI_GETKEYBOARDCUES.
SPI_GETSELECTIONFADE	Determines whether the selection fade effect is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled or FALSE if disabled. The selection fade effect causes the menu item selected by the user to remain on the screen briefly while fading out after the menu is dismissed.
SPI_GETTOOLTIPANIMATION	Determines whether ToolTip animation is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled or FALSE if disabled. If ToolTip animation is enabled, SPI_GETTOOLTIPFADE indicates whether ToolTips use fade or slide animation.
SPI_GETTOOLTIPFADE	If SPI_SETTOOLTIPANIMATION is enabled, SPI_GETTOOLTIPFADE indicates whether ToolTip animation uses a fade effect or a slide effect. The pvParam parameter must point to a BOOL variable that receives TRUE for fade animation or FALSE for slide animation. For more information on slide and fade effects, see AnimateWindow.
SPI_GETUIEFFECTS	Determines whether UI effects are enabled or disabled. The pvParam parameter must point to a BOOL variable that receives TRUE if all UI effects are enabled, or FALSE if they are disabled.
SPI_SETCOMBOBOXANIMATION	Enables or disables the slide-open effect for combo boxes. Set the pvParam parameter to TRUE to enable the gradient effect, or FALSE to disable it.
SPI_SETCURSORSHADOW	Enables or disables a shadow around the cursor. The pvParam parameter is a BOOL variable. Set pvParam to TRUE to enable the shadow or FALSE to disable the shadow. This effect appears only if the system has a color depth of more than 256 colors.
SPI_SETGRADIENTCAPTIONS	Enables or disables the gradient effect for window title bars. Set the pvParam parameter to TRUE to enable it, or FALSE to disable it. The gradient effect is possible only if the system has a color depth of more than 256 colors. For more information about the gradient effect, see the GetSysColor function.
SPI_SETHOTTRACKING	Enables or disables hot tracking of user-interface elements such as menu names on menu bars. Set the pvParam parameter to TRUE to enable it, or FALSE to disable it. Hot-tracking means that when the cursor moves over an item, it is highlighted but not selected.
SPI_SETLISTBOXSMOOTHSCROLLING	Enables or disables the smooth-scrolling effect for list boxes. Set the pvParam parameter to TRUE to enable the smooth-scrolling effect, or FALSE to disable it.
SPI_SETMENUANIMATION	Enables or disables menu animation. This master switch must be on for any menu animation to occur. The pvParam parameter is a BOOL variable; set pvParam to TRUE to enable animation and FALSE to disable animation. If animation is enabled, SPI_GETMENUFADE indicates whether menus use fade or slide animation.
SPI_SETMENUUNDERLINES	Same as SPI_SETKEYBOARDCUES.
SPI_SETSELECTIONFADE	Set pvParam to TRUE to enable the selection fade effect or FALSE to disable it. The selection fade effect causes the menu item selected by the user to remain on the screen briefly while fading out after the menu is dismissed. The selection fade effect is possible only if the system has a color depth of more than 256 colors.
SPI_SETTOOLTIPANIMATION	Set pvParam to TRUE to enable ToolTip animation or FALSE to disable it. If enabled, you can use SPI_SETTOOLTIPFADE to specify fade or slide animation.
SPI_SETTOOLTIPFADE	If the SPI_SETTOOLTIPANIMATION flag is enabled, use SPI_SETTOOLTIPFADE to indicate whether ToolTip animation uses a fade effect or a slide effect. Set pvParam to TRUE for fade animation or FALSE for slide animation. The tooltip fade effect is possible only if the system has a color depth of more than 256 colors. For more information on the slide and fade effects, see the AnimateWindowfunction.
SPI_SETUIEFFECTS	Enables or disables UI effects. Set the pvParam parameter to TRUE to enable all UI effects or FALSE to disable all UI effects.

The following are the window parameters.

Window parameter	Meaning
SPI_GETACTIVEWINDOWTRACKING	Determines whether active window tracking (activating the window the mouse is on) is on or off. The pvParam parameter must point to a BOOL variable that receives TRUE for on, or FALSE for off.
SPI_GETACTIVEWNDTRKZORDER	Determines whether windows activated through active window tracking will be brought to the top. The pvParam parameter must point to a BOOL variable that receives TRUE for on, or FALSE for off.
SPI_GETACTIVEWNDTRKTIMEOUT	Retrieves the active window tracking delay, in milliseconds. The pvParam parameter must point to a DWORD variable that receives the time.
SPI_GETANIMATION	Retrieves the animation effects associated with user actions. The pvParam parameter must point to an ANIMATIONINFO structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(ANIMATIONINFO).
SPI_GETBORDER	Retrieves the border multiplier factor that determines the width of a window's sizing border. The pvParam parameter must point to an integer variable that receives this value.
SPI_GETCARETWIDTH	Retrieves the caret width in edit controls, in pixels. The pvParam parameter must point to a DWORD variable that receives this value.
SPI_GETDRAGFULLWINDOWS	Determines whether dragging of full windows is enabled. The pvParam parameter must point to a BOOL variable that receives TRUE if enabled, or FALSE otherwise.
SPI_GETFOREGROUNDFLASHCOUNT	Retrieves the number of times SetForegroundWindow will flash the taskbar button when rejecting a foreground switch request. The pvParam parameter must point to a DWORD variable that receives the value.
SPI_GETFOREGROUNDLOCKTIMEOUT	Retrieves the amount of time following user input, in milliseconds, during which the system will not allow applications to force themselves into the foreground. The pvParam parameter must point to a DWORD variable that receives the time.
SPI_GETMINIMIZEDMETRICS	Retrieves the metrics associated with minimized windows. The pvParam parameter must point to a MINIMIZEDMETRICS structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(MINIMIZEDMETRICS).
SPI_GETNONCLIENTMETRICS	Retrieves the metrics associated with the nonclient area of nonminimized windows. The pvParam parameter must point to a NONCLIENTMETRICS structure that receives the information. Set the cbSize member of this structure and the uiParam parameter to sizeof(NONCLIENTMETRICS).
SPI_GETSHOWIMEUI	Determines whether the IME status window is visible (on a per-user basis). The pvParam parameter must point to a BOOL variable that receives TRUE if the status window is visible, or FALSE if it is not.
SPI_SETACTIVEWINDOWTRACKING	Sets active window tracking (activating the window the mouse is on) either on or off. Set pvParam to TRUE for on or FALSE for off.
SPI_SETACTIVEWNDTRKZORDER	Determines whether or not windows activated through active window tracking should be brought to the top. Set pvParam to TRUE for on or FALSE for off.
SPI_SETACTIVEWNDTRKTIMEOUT	Sets the active window tracking delay. Set pvParam to the number of milliseconds to delay before activating the window under the mouse pointer.
SPI_SETANIMATION	Sets the animation effects associated with user actions. The pvParam parameter must point to an ANIMATIONINFO structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(ANIMATIONINFO).
SPI_SETBORDER	Sets the border multiplier factor that determines the width of a window's sizing border. The uiParam parameter specifies the new value.
SPI_SETCARETWIDTH	Sets the caret width in edit controls. Set pvParam to the desired width, in pixels. The default and minimum value is 1.
SPI_SETDRAGFULLWINDOWS	Sets dragging of full windows either on or off. The uiParam parameter specifies TRUE for on, or FALSE for off.
SPI_SETDRAGHEIGHT	Sets the height, in pixels, of the rectangle used to detect the start of a drag operation. Set uiParam to the new value. To retrieve the drag height, call GetSystemMetrics with the SM_CYDRAG flag.
SPI_SETDRAGWIDTH	Sets the width, in pixels, of the rectangle used to detect the start of a drag operation. Set uiParam to the new value. To retrieve the drag width, call GetSystemMetrics with the SM_CXDRAG flag.
SPI_SETFOREGROUNDFLASHCOUNT	Sets the number of times SetForegroundWindow will flash the taskbar button when rejecting a foreground switch request. Set pvParam to the number of times to flash.
SPI_SETFOREGROUNDLOCKTIMEOUT	Sets the amount of time following user input, in milliseconds, during which the system does not allow applications to force themselves into the foreground. Set pvParam to the new time-out value. The calling thread must be able to change the foreground window, otherwise the call fails.
SPI_SETMINIMIZEDMETRICS	Sets the metrics associated with minimized windows. The pvParam parameter must point to a MINIMIZEDMETRICS structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(MINIMIZEDMETRICS).
SPI_SETNONCLIENTMETRICS	Sets the metrics associated with the nonclient area of nonminimized windows. The pvParam parameter must point to a NONCLIENTMETRICS structure that contains the new parameters. Set the cbSize member of this structure and the uiParam parameter to sizeof(NONCLIENTMETRICS). Also, the lfHeight member of the LOGFONT structure must be a negative value.
SPI_SETSHOWIMEUI	Sets whether the IME status window is visible or not on a per-user basis. The uiParam parameter specifies TRUE for on or FALSE for off.

uiParam [in]

A parameter whose usage and format depends on the system parameter being queried or set. For more information about system-wide parameters, see the uiAction parameter. If not otherwise indicated, you