According to both MSDN and our impementation, GetBufferSize returns the
size of the buffer, but it doesn't guarantee that all of it is available.
In order to know how much of it is available, the caller must also call
GetCurrentPadding and subtract that number to the buffer size. Failing
to do so might result in GetBuffer returning an error.
Signed-off-by: Giovanni Mascellani <gmascellani@codeweavers.com>
Signed-off-by: Nikolay Sivov <nsivov@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>