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MapVirtualKeyA function (winuser.h)

  • Article

Translates (maps) a virtual-key code into a scan code or character value, or translates a scan code into a virtual-key code.

Syntax

UINT MapVirtualKeyA(
  [in] UINT uCode,
  [in] UINT uMapType
);

Parameters

[in] uCode

Type: UINT

The virtual key code or scan code for a key. How this value is interpreted depends on the value of the uMapType parameter.

[in] uMapType

Type: UINT

The translation to be performed. The value of this parameter depends on the value of the uCode parameter.

Value Meaning
MAPVK_VK_TO_VSC
0		 The uCode parameter is a virtual-key code and is translated into a scan code. If it is a virtual-key code that does not distinguish between left- and right-hand keys, the left-hand scan code is returned. If there is no translation, the function returns 0.
MAPVK_VSC_TO_VK
1		 The uCode parameter is a scan code and is translated into a virtual-key code that does not distinguish between left- and right-hand keys. If there is no translation, the function returns 0.
Windows Vista and later: the high byte of the uCode value can contain either 0xe0 or 0xe1 to specify the extended scan code.
MAPVK_VK_TO_CHAR
2		 The uCode parameter is a virtual-key code and is translated into an unshifted character value in the low order word of the return value. Dead keys (diacritics) are indicated by setting the top bit of the return value. If there is no translation, the function returns 0. See Remarks.
MAPVK_VSC_TO_VK_EX
3		 The uCode parameter is a scan code and is translated into a virtual-key code that distinguishes between left- and right-hand keys. If there is no translation, the function returns 0.
Windows Vista and later: the high byte of the uCode value can contain either 0xe0 or 0xe1 to specify the extended scan code.
MAPVK_VK_TO_VSC_EX
4		 Windows Vista and later: The uCode parameter is a virtual-key code and is translated into a scan code. If it is a virtual-key code that does not distinguish between left- and right-hand keys, the left-hand scan code is returned. If the scan code is an extended scan code, the high byte of the returned value will contain either 0xe0 or 0xe1 to specify the extended scan code. If there is no translation, the function returns 0.

Return value

Type: UINT

The return value is either a scan code, a virtual-key code, or a character value, depending on the value of uCode and uMapType. If there is no translation, the return value is zero.

Remarks

To specify a handle to the keyboard layout to use for translating the specified code, use the MapVirtualKeyEx function.

An application can use MapVirtualKey to translate scan codes to the virtual-key code constants VK_SHIFT, VK_CONTROL, and VK_MENU, and vice versa. These translations do not distinguish between the left and right instances of the SHIFT, CTRL, or ALT keys.

An application can get the scan code corresponding to the left or right instance of one of these keys by calling MapVirtualKey with uCode set to one of the following virtual-key code constants:

  • VK_LSHIFT
  • VK_RSHIFT
  • VK_LCONTROL
  • VK_RCONTROL
  • VK_LMENU
  • VK_RMENU

These left- and right-distinguishing constants are available to an application only through the GetKeyboardState, SetKeyboardState, GetAsyncKeyState, GetKeyState, MapVirtualKey, and MapVirtualKeyEx functions. For list complete table of virtual key codes, see Virtual Key Codes.

In MAPVK_VK_TO_CHAR mode virtual-key codes, the 'A'..'Z' keys are translated to upper-case 'A'..'Z' characters regardless of current keyboard layout. If you want to translate a virtual-key code to the corresponding character, use the ToAscii function.

Note

The winuser.h header defines MapVirtualKey as an alias that automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that is not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.

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

See also