I want to wake system from sleep programmatically, is there any way to do this?
I have read following link:
http://developer.apple.com/mac/library/qa/qa2004/qa1340.html
this only talk about getting notification , but not sure is there any way to wake system from sleep?
I appreciate some thread to the information...
Update:
As per the suggestion I tried with IOPMSchedulePowerEvent
Code I have used:
NSCalendarDate *timeIntervalSinceNow = [NSCalendarDate dateWithTimeIntervalSinceNow:40];
IOReturn result = IOPMSchedulePowerEvent ((CFDateRef)timeIntervalSinceNow, NULL, CFSTR(kIOPMAutoWake));
Result:
It fails in MacBook if lid closed
Am I doing some thing wrong or Any solution?
You can schedule wake up events with IOPMSchedulePowerEvent through the power manager. You may be able to schedule an immediate wake up. pmset is a command line wrapper for the power manager. You can also prevent sleep with IOCancelPowerChange in certain cases.
You may be able to prevent sleep or wake up by generating a mouse or key event. One way to generate events is with CGPostKeyboardEvent.
Edit:
Normal sleep is different from clamshell closed sleep. To affect the latter you must write a kernel extension like Insomnia.
Related
I want to use UP3 for a very specific task, which I should be able to implement using API. I am trying to understand, is it possiblу to write a following application.
Basing on https://jawbone.com/support/articles/000005231/tracking-sleep , the UP3 can catch switching between sleep phases. I need, for example, catch a Light Sleep beginning, wait for 80 seconds and then vibrate for waking up. Can it be done?
After reading documentation I do not understand fundamental applications architecture. I assume, that there should be opened bluetooth channel, and, for example, every 10 seconds I write to the channel sleep status request with 1-2 seconds feedback. Then I write "awake" command which tells the band to vibrate.
Another scenario - somehow I get notification about sleep phase swithcing. Then I start timer, and send this wake-up command.
But these are just my theories. Please explain me, can it be done and how?
The short answer to your question is no, this cannot be done.
Here's why:
Changes in sleep phase are calculated server-side after the entire sleep event has occurred, so there is no way to receive a real-time notification for a sleep phase change. Here's another SO question with additional details about this and on how to receive sleep event notifications.
Jawbone does not allow third party applications to trigger band vibration. Here's another SO question with details on why.
Jawbone does not allow third party applications to connect directly to the band over bluetooth.
I know how waitpid(-1...) allows me to wait until all children have finished, such as waitpid(-1, &status). But how can I wait until all background processes are finished? Someone suggested that I can use the same waitpid (in a loop?) to achieve this but I don't see how.
To be clear, I'm implementing a shell, and need to add a new built-in command wait, which waits until all background jobs have terminated before returning to the prompt.
I read somewhere else on SO that "You will also want to call waitpid() with the WNOHANG option regularly - say, immediately before you display the shell prompt. This will allow you to detect when the background process has exited or stopped " But again, child != background. So even that I don't believe.
Edit:
I ended up just doing while(wait(NULL) > 0); and that's it, it worked. But what I'm still confused about is don't I WANT to make a distinction between foreground and background because the wait I'm implementing only waits for the background processes, and all children are equal in the eye of wait() or waitpid().
So again, the children I'm waiting for by using wait() or waitpid() aren't necessarily background processes. Am I wrong?
Since you ask in the context of implementing a shell, and evidently your shell supports enough job control to have a concept of background processes, it is reasonable to suppose that your implementation will have a table in which it tracks background jobs. That table can and should track the PID of the process associated with each job.
Having those PIDs in hand, you can waitpid() for specific background jobs until there are no more in the table, or you can waitpid(-1) to collect
any and every job, in a loop, until there are no more background jobs in the table.
If you want to implement background process (and job control) and catch their termination (at least) you must set a signal handler for SIGCHLD, and call wait(-1) inside it. This will let your shell receive asynchronous notifications of background processes termination. You may have a look at Catching SIGCHLD for example and discussion about this.
What's the best way of detecting when a user has been idle for X amount of time, and then detect when the user becomes immediately active?
I know there's NSWorkspace which provides will/did sleep/wake notifications, but I can't rely on that because the sleep setting is usually about ~15 minutes to never. I need to be able to detect if the user's been idle for ~1-2 minutes.
This answer provides a way to get the idle time. I'd like to avoid polling if possible.
Polling is your only option, to my knowledge. As user1118321 points out, polling every O(minutes) is unlikely to cause any problems, performance or otherwise.
If your app has a GUI and receives UI events anyway, you could install a handler via +[NSEvent addLocalMonitorForEventsMatchingMask:handler:] that resets your timer on each event. That'll help reduce if not eliminate polls when the user is consistently active, in your own app at least.
Once you've determined that the user has been idle long enough, you could then install a global event tap to watch for the next event. See for example -[NSEvent addGlobalMonitorForEventsMatchingMask:handler:].
Note: you should use CGEventSourceSecondsSinceLastEventType if at all possible rather than poking into the IO registry. It's a formal, supported API and may be more efficient. Not to mention it's way simpler. There's also UKIdleTimer though it relies on Carbon, so may not be applicable.
I am developping an objective c application and I would like to detect non responsives windows even if they are not own by my application.
Is there a way to be notified when a such case occurs?
Thanks in advance for your help,
Regards,
I think the only way to detect whether an window is hanging is to detect when its application is hanging. And I think the only way to - reliably - do this is to talk to it. Send it some inter-process message and await an action. I think that's exactly how the system detects it: there is some delay before the beach ball appears. And this is because the system sent a message and received no answer in x seconds.
What kind of message that might be is hard to say. Must be something that goes through the main event loop but can be sent by every application. I'm sure Google will be of some help finding it. I'm no pro in inter-process communications and would have to search as well.
You can use the Instruments application with a "Spin Monitor" instrument track. If you set it to monitor "All Processes", it will capture stack traces whenever an application hangs (doesn't process the main event loop for a long time).
I was wondering if there was a way that I could get notifications of when a system process from /usr/sbin starts and finishes. Is it possible to attach NSTask to the running process without launching a new one? Preferably without polling please :!
For UI process you can use NSRunningApplication. You can observe the "terminated" property to know when it finishes. You can listen to NSWorkspaceWillLaunchApplicationNotification to know when an application will be launched.
Since you're not running a UI application the above probably won't work. You'll have to use more low level BSD calls. Here's an example of how you can know when an process terminates:
https://developer.apple.com/library/content/technotes/tn2050/_index.html#//apple_ref/doc/uid/DTS10003081-CH1-SUBSECTION10
Good luck!