Time-Based
Notifications
You can
notify the operating system to send joystick messages to an application at
regular time intervals by setting the fChanged parameter of joySetCapture to FALSE and by specifying
the interval length between successive messages. To do this, assign the uPeriod
parameter a value between the minimum and maximum polling frequencies for the
joystick. You can determine this range by using the joyGetDevCaps function, which fills the wPeriodMin
and wPeriodMax members in the JOYCAPS19ISN8B structure. If the uPeriod value is
outside the range of valid polling frequencies for the joystick, the joystick
driver uses the minimum or maximum polling frequency, whichever is closer to
the uPeriod value.
Note Windows sets
up a timer event with each call to joySetCapture.