Instance Property


The system capabilities at the end of the transition.


uint32_t toCapabilities;

See Also



An identifier for this message notification. Clients with pending I/O can signal completion by calling allowPowerChange() with this value as the argument. Clients that are able to process the notification synchronously should ignore this field.


A return value to the caller indicating the maximum time in microseconds to wait for the allowPowerChange() call. The default value is zero, which indicates the client processing has finished, and power management should not wait for an allowPowerChange() call.


Flags will be set to indicate whether the notification precedes the capability change (kIOPMSystemCapabilityWillChange), or after the capability change has occurred (kIOPMSystemCapabilityDidChange).


Set to zero.


The system capabilities at the start of the transition.


Set to zero.

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

Learn more about using Apple's beta software