Sleep Demands

A sleep demand informs a routine that the Power Manager is about to put

the Macintosh Portable into the sleep state. When a routine in the sleep queue

receives a sleep demand, it must prepare for the sleep state as quickly as

possible and return control to the Power Manager.

The following figure illustrates the sequence of events that occurs when the

Power Manager issues a sleep demand.

How the sleep queue handles a sleep demand

From the point of view of the Power Manager, there are two types of sleep

demands-conditional and unconditional. The Power Manager might cancel a

conditional sleep demand if certain network services are in use; an

unconditional sleep demand cannot be canceled. When your sleep queue routine

receives a sleep demand, however, your routine has no way to determine

whether it originated as a conditional sleep demand or an unconditional sleep

demand. Your device driver or application must prepare for the sleep state

and return control promptly to the Power Manager when it receives a sleep

demand.

The Power Manager processes a conditional sleep demand when the user

chooses Sleep from the Battery desk accessory or from the Special menu in the

Finder. When the Power Manager processes a conditional sleep demand, it

first sends a sleep request to the network driver's sleep queue routine.

Whenever one of the network services is in use, the sleep queue routine

displays a dialog box requesting the user's permission to put the Macintosh

Portable into the sleep state. The wording of the message in the dialog box

depends on the nature of the network service in use. For example, if an .XPP

driver protocol is in use, has opened a server, and has mounted a volume, then

the message warns the user that the volume will be closed when the Macintosh

Portable is put into the sleep state.

If the user denies permission to close the driver, the Power Manager does

not send sleep demands to the routines in the sleep queue. If the user does give

permission to close the driver, the Power Manager sends a sleep demand to

the network driver's sleep queue routine and then to every other routine in the

sleep queue.

The Power Manager issues an unconditional sleep demand when the battery

voltage falls below a preset level or when the user chooses Shut Down from the

Special menu in the Finder. In this case, the Power Manager sends a sleep

demand to the network driver's sleep queue entry, which closes all network

drivers. Then the Power Manager sends a sleep demand to every other

routine in the sleep queue. As always for a sleep demand, each routine must

prepare for the sleep state and return control to the Power Manager as

quickly as possible. In this case, the Power Manager does not display any

warnings or dialog boxes; neither the network services, the user, nor any

application can deny the sleep demand.

Referenced by (2):