Handle external signals

From Green software

Signals originating from the operating system should always be explicitly handled by an application. Certain unhandled signals can stop a system or subsystem from going into a lower power state, which leads to unnecessary energy consumption.

When a system running Windows 7 wants to enter a state of suspension, a WM_POWERBROADCAST message with an event type of PBT_APMSUSPEND is sent to all applications. The applications receive this message iteratively, so applications that take a long time block the suspend path and add to the overall suspend time on the system [1].

References

[1]. The Science of Sleep (for Windows 7). 2010. Microsoft Corporation.

Sources

This best practice is mentioned in:
Petter Larsson. 2008. Energy-Efficient Software Guidelines. White Paper for the Intel Software Solutions Group.