Apple Newton Programmer’s Newton 2.0 (for Newton 2.0) - Manual (Page 642)

C H A P T E R 1 7
Additional System Services
17-26 Using Additional System Services
communications endpoint, it can return the 'holdYourHorses symbol to delay
shutdown. After completing the task for which you delayed shutdown, you must
call the
PowerOffResume function as soon as possible to resume the power-
off sequence.
Returning nil in response to the 'powerOff symbol allows the power-off
sequence to continue. Your callback function must return the value nil in response
to any symbols other than those described here.
The UnRegPowerOff function unregisters functions added with RegPowerOff .
IMPORTANT
The callback function registered with RegPowerOff must not
itself call RegPowerOff nor UnRegPowerOff . ▲
Using the Battery Information Functions 17
Two functions return battery-related information. The BatteryCount function
returns the count of installed battery packs. The BatteryStatus function returns
a frame with information about the status of a battery pack. This frame contains
information about the battery type and charge status, whether the Newton device is
plugged in, and other power-related data. Note that the contents of this frame differ
depending on the hardware responsible for the battery’s operation.