KBDLLHOOKSTRUCT

The KBDLLHOOKSTRUCT structure contains information about a low-level keyboard input event.

typedef struct tagKBDLLHOOKSTRUCT {
    DWORD     vkCode;
    DWORD     scanCode;
    DWORD     flags;
    DWORD     time;
    ULONG_PTR dwExtraInfo;
} KBDLLHOOKSTRUCT, *PKBDLLHOOKSTRUCT;

Members

vkCode

Specifies a virtual-key code. The code must be a value in the range 1 to 254.

scanCode

Specifies a hardware scan code for the key.

flags

Specifies the extended-key flag, event-injected flag, context code, and transition-state flag. This member is specified as follows.

Value	Description
0	Specifies whether the key is an extended key, such as a function key or a key on the numeric keypad. The value is 1 if the key is an extended key; otherwise, it is 0.
1-3	Reserved.
4	Specifies whether the event was injected. The value is 1 if the event was injected; otherwise, it is 0.
5	Specifies the context code. The value is 1 if the ALT key is pressed; otherwise, it is 0.
6	Reserved.
7	Specifies the transition state. The value is 0 if the key is pressed and 1 if it is being released.

An application can use the following values to test the keystroke flags.

Value	Purpose
LLKHF_EXTENDED	Test the extended-key flag.
LLKHF_INJECTED	Test the event-injected flag.
LLKHF_ALTDOWN	Test the context code.
LLKHF_UP	Test the transition-state flag.

time

Specifies the time stamp for this message.

dwExtraInfo

Specifies extra information associated with the message.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 SP3 or later.
  Windows 95/98: Unsupported.
  Header: Declared in Winuser.h; include Windows.h.

See Also

Hooks Overview, Hook Structures, LowLevelKeyboardProc, SetWindowsHookEx