Apple

Le 9 mars 2010 à 06:39, James Bucanek a écrit :

Greetings,

I'm not sure that Darwin-Dev is the right place to post this, but since this is essentially an IOKit question, it's the closest I could find to the topic.

I'm upgrading my app and would like to use IOPMAssertionCreate()/IOPMAssertionCreateWithName() to prohibit the computer from going to sleep while performing a backup. However, the documentation seems a little vague, which has left me wondering exactly how these functions should be used.

Do I:

(a) Call IOPMAssertionCreateWithName() when starting an action that should not be interrupted by sleep mode and then call IOPMAssertionRelease() when that's over.

Or (b) do I call IOPMAssertionCreateWithName() with kIOPMAssertionLevelOn when the action starts, immediately call IOPMAssertionRelease() to release the assertion_id, and then later call IOPMAssertionCreateWithName() with kIOPMAssertionLevelOff when the task is complete.

Or (c) ?

I guess my question is really "what sequence of calls establish and rescind the sleep mode prohibition?" I skimmed the IOKit documentation and didn't find anything illuminating. I couldn't find any example code that employed these calls.

TIA,

James

IOPMAssertionID assertionID;
IOReturn success = IOPMAssertionCreate(kIOPMAssertionTypeNoDisplaySleep,
                                    kIOPMAssertionLevelOn, &assertionID);
if (success == kIOReturnSuccess)
{

    //Add the work you need to do without
    //  the system sleeping here.

    success = IOPMAssertionRelease(assertionID);
    //The system will be able to sleep again.
}
...

References:
	>Correct use of IOPMAssertionCreateWithName(...) (From: James Bucanek <email@hidden>)