Question

I need to write code in C that will indicate and notify me when the laptop battery power is low. I know that I can use the following:

BOOL WINAPI GetSystemPowerStatus(
    __out  LPSYSTEM_POWER_STATUS lpSystemPowerStatus
    );

But I want to send a function to the operating system that will notify me when power is low.

I want to have an “empty” loop in my code, and when battery is low, the code will send me a notification (printf or trace).

I think I should be using kernel functions, but I can’t find them

Answer 1

I have never used these APIs, but what you are looking for seems to be WM_POWERBROADCAST.

There are various values for wParam that you could check upon receiving that message, such as PBT_APMBATTERYLOW. When you receive a WM_POWERBROADCAST message with the appropriate wParam value, call GetSystemPowerStatus() from there.