You can use GetAsyncKeyState.
Code:
BOOL IsLButtonDown(void)
{
return (GetAsyncKeyState(VK_LBUTTON) & 0x8000);
}
Note that MSDN says this:
Originally Posted by
MSDN GetAsyncKeyState
The GetAsyncKeyState function works with mouse buttons. However, it checks on the state of the physical mouse buttons, not on the logical mouse buttons that the physical buttons are mapped to. For example, the call GetAsyncKeyState(VK_LBUTTON) always returns the state of the left physical mouse button, regardless of whether it is mapped to the left or right logical mouse button. You can determine the system's current mapping of physical mouse buttons to logical mouse buttons by calling
GetSystemMetrics(SM_SWAPBUTTON)
which returns TRUE if the mouse buttons have been swapped.