ActivateKeyboardLayout function (winuser.h)

Article
10/13/2021

Sets the input locale identifier (formerly called the keyboard layout handle) for the calling thread or the current process. The input locale identifier specifies a locale as well as the physical layout of the keyboard.

Syntax

HKL ActivateKeyboardLayout(
  [in] HKL  hkl,
  [in] UINT Flags
);

Parameters

[in] hkl

Type: HKL

Input locale identifier to be activated.

The input locale identifier must have been loaded by a previous call to the LoadKeyboardLayout function. This parameter must be either the handle to a keyboard layout or one of the following values.

Value	Meaning
HKL_NEXT 1	Selects the next locale identifier in the circular list of loaded locale identifiers maintained by the system.
HKL_PREV 0	Selects the previous locale identifier in the circular list of loaded locale identifiers maintained by the system.

[in] Flags

Type: UINT

Specifies how the input locale identifier is to be activated. This parameter can be one of the following values.

Value	Meaning
KLF_REORDER 0x00000008	If this bit is set, the system's circular list of loaded locale identifiers is reordered by moving the locale identifier to the head of the list. If this bit is not set, the list is rotated without a change of order. For example, if a user had an English locale identifier active, as well as having French, German, and Spanish locale identifiers loaded (in that order), then activating the German locale identifier with the KLF_REORDER bit set would produce the following order: German, English, French, Spanish. Activating the German locale identifier without the KLF_REORDER bit set would produce the following order: German, Spanish, English, French. If less than three locale identifiers are loaded, the value of this flag is irrelevant.
KLF_RESET 0x40000000	If set but KLF_SHIFTLOCK is not set, the Caps Lock state is turned off by pressing the Caps Lock key again. If set and KLF_SHIFTLOCK is also set, the Caps Lock state is turned off by pressing either SHIFT key. These two methods are mutually exclusive, and the setting persists as part of the User's profile in the registry.
KLF_SETFORPROCESS 0x00000100	Activates the specified locale identifier for the entire process and sends the WM_INPUTLANGCHANGE message to the current thread's focus or active window.
KLF_SHIFTLOCK 0x00010000	This is used with KLF_RESET. See KLF_RESET for an explanation.
KLF_UNLOADPREVIOUS	This flag is unsupported. Use the UnloadKeyboardLayout function instead.

Return value

Type: HKL

The return value is of type HKL. If the function succeeds, the return value is the previous input locale identifier. Otherwise, it is zero.

To get extended error information, use the GetLastError function.

Remarks

This function only affects the layout for the current process or thread.

This function is not restricted to keyboard layouts. The hkl parameter is actually an input locale identifier. This is a broader concept than a keyboard layout, since it can also encompass a speech-to-text converter, an Input Method Editor (IME), or any other form of input. Several input locale identifiers can be loaded at any one time, but only one is active at a time. Loading multiple input locale identifiers makes it possible to rapidly switch between them.

When multiple IMEs are allowed for each locale, passing an input locale identifier in which the high word (the device handle) is zero activates the first IME in the list belonging to the locale.

The KLF_RESET and KLF_SHIFTLOCK flags alter the method by which the Caps Lock state is turned off. By default, the Caps Lock state is turned off by hitting the Caps Lock key again. If only KLF_RESET is set, the default state is reestablished. If KLF_RESET and KLF_SHIFTLOCK are set, the Caps Lock state is turned off by pressing either Caps Lock key. This feature is used to conform to local keyboard behavior standards as well as for personal preferences.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	winuser.h (include Windows.h)
Library	User32.lib
DLL	User32.dll