The keybd_event function synthesizes a keystroke. The system can use such a synthesized keystroke to generate a WM_KEYUP or WM_KEYDOWN message. The keyboard driver's interrupt handler calls the keybd_event function.
VOID keybd_event(
| BYTE bVk, | // virtual-key code |
| BYTE bScan, | // hardware scan code |
| DWORD dwFlags, | // flags specifying various function options |
| DWORD dwExtraInfo | // additional data associated with keystroke |
| ); |
Parameters
bVk
Specifies a virtual-key code. The code must be a value in the range 1 to 254.
bScan
Specifies a hardware scan code for the key.
dwFlags
A set of flag bits that specify various aspects of function operation. An application can use any combination of the following predefined constant values to set the flags:
| Value | Meaning |
| KEYEVENTF_EXTENDEDKEY | If specified, the scan code was preceded by a prefix byte having the value 0xE0 (224). |
| KEYEVENTF_KEYUP | If specified, the key is being released. If not specified, the key is being depressed. |
dwExtraInfo
Specifies an additional 32-bit value associated with the key stroke.
Return Values
This function has no return value.
Remarks
Although keybd_event passes an OEM-dependent hardware scan code to Windows, applications should not use the scan code. Windows converts scan codes to virtual-key codes internally and clears the up/down bit in the scan code before passing it to applications.
An application can simulate a press of the PRINTSCREEN key in order to obtain a screen snapshot and save it to the Windows clipboard. To do this, call keybd_event with the bVk parameter set to VK_SNAPSHOT, and the bScan parameter set to 0 for a snapshot of the full screen or set bScan to 1 for a snapshot of the active window.
See Also
GetAsyncKeyState, GetKeyState, MapVirtualKey, SetKeyboardState