Function IOPSGetTimeRemainingEstimate 

pub extern "C-unwind" fn IOPSGetTimeRemainingEstimate() -> CFTimeInterval

Available on crate feature ps only.

Returns the estimated minutes remaining until all power sources (battery and/or UPS’s) are empty, or returns

 kIOPSTimeRemainingUnlimited

if attached to an unlimited power source.

If attached to an “Unlimited” power source, like AC power or any external source, the return value is

 kIOPSTimeRemainingUnlimited

If the system is on “Limited” power, like a battery or UPS, but is still calculating the time remaining, which may take several seconds after each system power event (e.g. waking from sleep, or unplugging AC Power), the return value is

 kIOPSTimeRemainingUnknown

Otherwise, if the system is on “Limited” power and the system has an accurate time remaining estimate, the system returns a CFTimeInterval estimate of the time remaining until the system is out of battery power.

If you require more detailed battery information, use

 IOPSCopyPowerSourcesInfo

and

 IOPSGetPowerSourceDescription

.

Returns: Returns

 kIOPSTimeRemainingUnknown

if the OS cannot determine the time remaining.

Returns

 kIOPSTimeRemainingUnlimited

if the system has an unlimited power source.

Otherwise returns a positive number of type CFTimeInterval, indicating the time remaining in seconds until all power sources are depleted.