You do not need to stop apps from running imt background because almost no apps actually do run in the background. That, however, is for a different discussion. If you want to see your recent apps - double tap the home button to bring up the task bar at the bottom of the iPad. Tap and hold down on any icon in there until all of the icons wiggle. Not that long ago, iOS apps running in the background on your iPhone or iPad were essentially stuck in suspended animation, unable to do anything (besides trigger alerts via Apple’s “push. How to Get Your Mac's Dock to Show Running Apps Only Friday March 30, 2018 2:53 AM PDT by Tim Hardwick Last week we explained how you can use a simple Terminal command to insert spaces in your.
For iOS apps, it is crucial to know whether your app is running in the foreground or the background. An app must behave differently in the background than in the foreground, because system resources are more limited on iOS devices. For an overall discussion of background operation on iOS, see Background Execution in App Programming Guide for iOS.
By default, many of the common Core Bluetooth tasks—on both the central and peripheral side—are disabled while your app is in the background or in a suspended state. That said, you can declare your app to support the Core Bluetooth background execution modes to allow your app to be woken up from a suspended state to process certain Bluetooth-related events. Even if your app doesn’t need the full range of background processing support, it can still ask to be alerted by the system when important events occur.
Even if your app supports one or both of the Core Bluetooth background execution modes, it can’t run forever. At some point, the system may need to terminate your app to free up memory for the current foreground app—causing any active or pending connections to be lost, for instance. As of iOS 7, Core Bluetooth supports saving state information for central and peripheral manager objects and restoring that state at app launch time. You can use this feature to support long-term actions involving Bluetooth devices.
Foreground-Only Apps
As with most iOS apps, unless you request permission to perform specific background tasks, your app transitions to the suspended state shortly after entering the background state. While in the suspended state, your app is unable to perform Bluetooth-related tasks, nor is it aware of any Bluetooth-related events until it resumes to the foreground.
On the central side, foreground-only apps—apps that have not declared to support either of the Core Bluetooth background execution modes—cannot scan for and discover advertising peripherals while in the background or while suspended. On the peripheral side, advertising is disabled, and any central trying to access a dynamic characteristic value of one of the app’s published services receives an error.
Depending on the use case, this default behavior can affect your app in several ways. As an example, imagine that you are interacting with the data on a peripheral that you’re currently connected to. Now imagine that your app moves to the suspended state (because, for example, the user switches to another app). If the connection to the peripheral is lost while your app is suspended, you won’t be aware that any disconnection occurred until your app resumes to the foreground.
Take Advantage of Peripheral Connection Options
All Bluetooth-related events that occur while a foreground-only app is in the suspended state are queued by the system and delivered to the app only when it resumes to the foreground. That said, Core Bluetooth provides a way to alert the user when certain central role events occur. Best todo app for mac 2017. The user can then use these alerts to decide whether a particular event warrants bringing the app back to the foreground.
You can take advantage of these alerts by including one of the following peripheral connection options when calling the
connectPeripheral:options:
method of the CBCentralManager
class to connect to a remote peripheral: https://vwylef.weebly.com/color-palette-mac-app.html.CBConnectPeripheralOptionNotifyOnConnectionKey
—Include this key if you want the system to display an alert for a given peripheral if the app is suspended when a successful connection is made.CBConnectPeripheralOptionNotifyOnDisconnectionKey
—Include this key if you want the system to display a disconnection alert for a given peripheral if the app is suspended at the time of the disconnection.CBConnectPeripheralOptionNotifyOnNotificationKey
—Include this key if you want the system to display an alert for all notifications received from a given peripheral if the app is suspended at the time.
For more information about the peripheral connection options, see the
Peripheral Connection Options
constants, detailed in CBCentralManager Class Reference.Core Bluetooth Background Execution Modes
If your app needs to run in background to perform certain Bluetooth-related tasks, it must declare that it supports a Core Bluetooth background execution mode in its Information property list (
Info.plist
) file. When your app declares this, the system wakes it up from a suspended state to allow it to handle Bluetooth-related events. This support is important for apps that interact with Bluetooth low energy devices that deliver data at regular intervals, such as a heart rate monitor.There are two Core Bluetooth background execution modes that an app may declare—one for apps implementing the central role, and another for apps implementing the peripheral role. If your app implements both roles, it may declare that it supports both background execution modes. The Core Bluetooth background execution modes are declared by adding the
UIBackgroundModes
key to your Info.plist
file and setting the key’s value to an array containing one of the following strings:bluetooth-central
—The app communicates with Bluetooth low energy peripherals using the Core Bluetooth framework.bluetooth-peripheral
—The app shares data using the Core Bluetooth framework.
Note: The property list editor in Xcode by default displays human-readable strings for many keys instead of the actual key name. To display the actual key names as they appear in the
Info.plist
file, Control-click any of the keys in the editor window and enable the Show Raw Keys/Values item in the contextual window.For information about how to configure the contents of your
Info.plist
file, see Xcode Help.The bluetooth-central Background Execution Mode
When an app that implements the central role includes the
UIBackgroundModes
key with the bluetooth-central
value in its Info.plist
file, the Core Bluetooth framework allows your app to run in the background to perform certain Bluetooth-related tasks. While your app is in the background you can still discover and connect to peripherals, and explore and interact with peripheral data. In addition, the system wakes up your app when any of the CBCentralManagerDelegate
or CBPeripheralDelegate
delegate methods are invoked, allowing your app to handle important central role events, such as when a connection is established or torn down, when a peripheral sends updated characteristic values, and when a central manager’s state changes.Although you can perform many Bluetooth-related tasks while your app is in the background, keep in mind that scanning for peripherals while your app is in the background operates differently than when your app is in the foreground. In particular, when your app is scanning for device while in the background:
- The
CBCentralManagerScanOptionAllowDuplicatesKey
scan option key is ignored, and multiple discoveries of an advertising peripheral are coalesced into a single discovery event. - If all apps that are scanning for peripherals are in the background, the interval at which your central device scans for advertising packets increases. As a result, it may take longer to discover an advertising peripheral.
These changes help minimize radio usage and improve the battery life on your iOS device.
The bluetooth-peripheral Background Execution Mode
To perform certain peripheral role tasks while in the background, you must include the
UIBackgroundModes
key with the bluetooth-peripheral
value in your app’s Info.plist
file. When this key-value pair is included in the app’s Info.plist
file, the system wakes up your app to process read, write, and subscription events.In addition to allowing your app to be woken up to handle read, write, and subscription requests from connected centrals, the Core Bluetooth framework allows your app to advertise while in the background state. That said, you should be aware that advertising while your app is in the background operates differently than when your app is in the foreground. In particular, when your app is advertising while in the background:
- The
CBAdvertisementDataLocalNameKey
advertisement key is ignored, and the local name of peripheral is not advertised. - All service UUIDs contained in the value of the
CBAdvertisementDataServiceUUIDsKey
advertisement key are placed in a special “overflow” area; they can be discovered only by an iOS device that is explicitly scanning for them. - If all apps that are advertising are in the background, the frequency at which your peripheral device sends advertising packets may decrease.
Use Background Execution Modes Wisely
Although declaring your app to support one or both of the Core Bluetooth background execution modes may be necessary to fulfill a particular use case, you should always perform background processing responsibly. Because performing many Bluetooth-related tasks require the active use of an iOS device’s onboard radio—and, in turn, radio usage has an adverse effect on an iOS device’s battery life—try to minimize the amount of work you do in the background. Apps woken up for any Bluetooth-related events should process them and return as quickly as possible so that the app can be suspended again.
Any app that declares support for either of the Core Bluetooth background executions modes must follow a few basic guidelines:
- Apps should be session based and provide an interface that allows the user to decide when to start and stop the delivery of Bluetooth-related events.
- Upon being woken up, an app has around 10 seconds to complete a task. Ideally, it should complete the task as fast as possible and allow itself to be suspended again. Apps that spend too much time executing in the background can be throttled back by the system or killed.
- Apps should not use being woken up as an opportunity to perform extraneous tasks that are unrelated to why the app was woken up by the system.
For more-general information about how your app should be behave in the background state, see Being a Responsible Background App in App Programming Guide for iOS.
Performing Long-Term Actions in the Background
Some apps may need to use the Core Bluetooth framework to perform long-term actions in the background. As an example, imagine you are developing a home security app for an iOS device that communicates with a door lock (equipped with Bluetooth low energy technology). The app and the lock interact to automatically lock the door when the user leaves home and unlock the door when the user returns—all while the app is in the background. When the user leaves home, the iOS device may eventually become out of range of the lock, causing the connection to the lock to be lost. At this point, the app can simply call the
connectPeripheral:options:
method of the CBCentralManager
class, and because connection requests do not time out, the iOS device will reconnect when the user returns home.Now imagine that the user is away from home for a few days. If the app is terminated by the system while the user is away, the app will not be able to reconnect to the lock when the user returns home, and the user may not be able to unlock the door. For apps like these, it is critical to be able to continue using Core Bluetooth to perform long-term actions, such as monitoring active and pending connections.
State Preservation and Restoration
Because state preservation and restoration is built in to Core Bluetooth, your app can opt in to this feature to ask the system to preserve the state of your app’s central and peripheral managers and to continue performing certain Bluetooth-related tasks on their behalf, even when your app is no longer running. When one of these tasks completes, the system relaunches your app into the background and gives your app the opportunity to restore its state and to handle the event appropriately. In the case of the home security app described above, the system would monitor the connection request, and re-relaunch the app to handle the
centralManager:didConnectPeripheral:
delegate callback when the user returned home and the connection request completed.Core Bluetooth supports state preservation and restoration for apps that implement the central role, peripheral role, or both. When your app implements the central role and adds support for state preservation and restoration, the system saves the state of your central manager object when the system is about to terminate your app to free up memory (if your app has multiple central managers, you can choose which ones you want the system to keep track of). In particular, for a given
CBCentralManager
object, the system keeps track of:- The services the central manager was scanning for (and any scan options specified when the scan started)
- The peripherals the central manager was trying to connect to or had already connected to
- Precision auto tune catonsville. The characteristics the central manager was subscribed to
Apps that implement the peripheral role can likewise take advantage of state preservation and restoration. For
CBPeripheralManager
objects, the system keeps track of:![Show Show](/uploads/1/3/4/1/134186821/273285927.jpg)
- The data the peripheral manager was advertising
- The services and characteristics the peripheral manager published to the device’s database
- The centrals that were subscribed to your characteristics’ values
When your app is relaunched into the background by the system (because a peripheral your app was scanning for is discovered, for instance), you can reinstantiate your app’s central and peripheral managers and restore their state. The following section describes in detail how to take advantage of state preservation and restoration in your app.
Adding Support for State Preservation and Restoration
State preservation and restoration in Core Bluetooth is an opt-in feature and requires help from your app to work. You can add support for this feature in your app by following this process:
- (Required) Opt in to state preservation and restoration when you allocate and initialize a central or peripheral manager object. This step is described in Opt In to State Preservation and Restoration.
- https://powerupstop.weebly.com/drake-take-care-free-mp3-download.html. (Required) Reinstantiate any central or peripheral manager objects after your app is relaunched by the system. This step is described in Reinstantiate Your Central and Peripheral Managers.
- (Required) Implement the appropriate restoration delegate method. This step is described in Implement the Appropriate Restoration Delegate Method.
- (Optional) Update your central and peripheral managers’ initialization process. This step is described in Update Your Initialization Process.
Opt In to State Preservation and Restoration
To opt in to the state preservation and restoration feature, simply provide a unique restoration identifier when you allocate and initialize a central or peripheral manager. A restoration identifier is a string that identifies the central or peripheral manager to Core Bluetooth and to your app. The value of the string is significant only to your code, but the presence of this string tells Core Bluetooth that it needs to preserve the state of the tagged object. Core Bluetooth preserves the state of only those objects that have a restoration identifier.
For example, to opt in to state preservation and restoration in an app that uses only one instance of a
CBCentralManager
object to implement the central role, specify the CBCentralManagerOptionRestoreIdentifierKey
initialization option and provide a restoration identifier for the central manager when you allocate and initialize it.Although the above example does not demonstrate this, you opt in to state preservation and restoration in an app that uses peripheral manager objects in an analogous way: Specify the
CBPeripheralManagerOptionRestoreIdentifierKey
initialization option, and provide a restoration identifier when you allocate and initialize each peripheral manager object.Note: Because apps can have multiple instances of
CBCentralManager
and CBPeripheralManager
objects, be sure each restoration identifier is unique, so that the system can properly distinguish one central (or peripheral) manager object from another.Reinstantiate Your Central and Peripheral Managers
When your app is relaunched into the background by the system, the first thing you need to do is reinstantiate the appropriate central and peripheral managers with the same restoration identifiers as they had when they were first created. If your app uses only one central or peripheral manager, and that manager exists for the lifetime of your app, there is nothing more you need to do for this step.
If your app uses more than one central or peripheral manager or if it uses a manager that isn’t around for the lifetime of your app, your app needs to know which managers to reinstantiate when it is relaunched by the system. You can access a list of all the restoration identifiers for the manager objects the system was preserving for your app when it was terminated, by using the appropriate launch option keys (
UIApplicationLaunchOptionsBluetoothCentralsKey
or UIApplicationLaunchOptionsBluetoothPeripheralsKey
) when implementing your app delegate’s application:didFinishLaunchingWithOptions:
method.For example, when your app is relaunched by system, you can retrieve all the restoration identifiers for the central manager objects the system was preserving for your app, like this:
After you have the list of restoration identifiers, simply loop through it and reinstantiate the appropriate central manager objects.
Note: When your app is relaunched, the system provides restoration identifiers only for central and peripheral managers for which it was performing some Bluetooth-related task (while the app was no longer running). These launch option keys are described in more detail in UIApplicationDelegate Protocol Reference.
Implement the Appropriate Restoration Delegate Method
After you have reinstantiated the appropriate central and peripheral managers in your app, restore them by synchronizing their state with the state of the Bluetooth system. To bring your app up to speed with what the system has been doing on its behalf (while it was not running), you must implement the appropriate restoration delegate method. For central managers, implement the
centralManager:willRestoreState:
delegate method; for peripheral managers, implement the peripheralManager:willRestoreState:
delegate method.Important: For apps that opt in to the state preservation and restoration feature of Core Bluetooth, these are the first methods (
centralManager:willRestoreState:
and peripheralManager:willRestoreState:
) invoked when your app is relaunched into the background to complete some Bluetooth-related task. For apps that don’t opt in to state preservation (or if there is nothing to restore upon launch), the centralManagerDidUpdateState:
and peripheralManagerDidUpdateState:
delegate methods are invoked first instead.In both of the above delegate methods, the last parameter is a dictionary that contains information about the managers that were preserved at the time the app was terminated. For a list of the available dictionary keys, see the
Central Manager State Restoration Options
constants in CBCentralManagerDelegate Protocol Reference and the Peripheral_Manager_State_Restoration_Options
constants in CBPeripheralManagerDelegate Protocol Reference.To restore the state of a
CBCentralManager
object, use the keys to the dictionary that is provided in the centralManager:willRestoreState:
delegate method. As an example, if your central manager object had any active or pending connections at the time your app was terminated, the system continued to monitor them on your app’s behalf. As the following shows, you can use the CBCentralManagerRestoredStatePeripheralsKey
dictionary key to get of a list of all the peripherals (represented by CBPeripheral
objects) the central manager was connected to or was trying to connect to:What you do with the list of restored peripherals in the above example depends on the use case. For instance, if your app keeps a list of the peripherals the central manager discovers, you may want to add the restored peripherals to that list to keep references to them. As described in Connecting to a Peripheral Device After You’ve Discovered It, be sure to set a peripheral’s delegate to ensure that it receives the appropriate callbacks.
You can restore the state of a
CBPeripheralManager
object in a similar way by using the keys to the dictionary that is provided in the peripheralManager:willRestoreState:
delegate method.Update Your Initialization Process
After you have implemented the previous three required steps, you may want to take a look at updating your central and peripheral managers’ initialization process. Although this is an optional step, it can be important in ensuring that things run smoothly in your app. As an example, your app may have been terminated while it was in the middle of exploring the data of a connected peripheral. When your app is restored with this peripheral, it won’t know how far it made it the discovery process at the time it was terminated. You’ll want to make sure you’re starting from where you left off in the discovery process.
For example, when initializing your app in the
centralManagerDidUpdateState:
delegate method, you can find out if you successfully discovered a particular service of a restored peripheral (before your app was terminated), like this:As the above example shows, if the system terminated your app before it finished discovering the service, begin the exploring the restored peripheral’s data at that point by calling the
discoverServices:
. If your app discovered the service successfully, you can then check to see whether the appropriate characteristics were discovered (and whether you already subscribed to them). By updating your initialization process in this manner, you’ll ensure that you’re calling the right methods at the right time.Turns out a simple restart fixed my issues with this app! Glad to see it still works as I remembered, and I even found some new features while troubleshooting. Worth the money! Original review: I have been using this app for a long time now to sort out photos I've downloaded multiple times or copied by accident in both Apple Photos and Finder. In the Photos app on your Mac, select the item you want to export. Choose File Export Export number Photos. Click the Photo Kind pop-up menu and choose the file type for the exported photos. JPEG creates small-size files suitable for use with websites and other photo apps. https://vwylef.weebly.com/get-photos-out-of-photos-app-on-mac.html.
Copyright © 2013 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2013-09-18
Close Background Apps Mac
Components of some Linuxdesktop environments that are daemons include D-Bus, NetworkManager (here called unetwork), PulseAudio (usound), and Avahi.
In multitasking computer operating systems, a daemon (/ˈdiːmən/ or /ˈdeɪmən/)[1] is a computer program that runs as a background process, rather than being under the direct control of an interactive user. Traditionally, the process names of a daemon end with the letter d, for clarification that the process is in fact a daemon, and for differentiation between a daemon and a normal computer program. For example, syslogd is a daemon that implements system logging facility, and sshd is a daemon that serves incoming SSH connections.
In a Unix environment, the parent process of a daemon is often, but not always, the init process. A daemon is usually created either by a process forking a child process and then immediately exiting, thus causing init to adopt the child process, or by the init process directly launching the daemon. In addition, a daemon launched by forking and exiting typically must perform other operations, such as dissociating the process from any controlling terminal (tty). Such procedures are often implemented in various convenience routines such as daemon(3) in Unix.
Systems often start daemons at boot time that will respond to network requests, hardware activity, or other programs by performing some task. Daemons such as cron may also perform defined tasks at scheduled times.
Terminology[edit]
The term was coined by the programmers at MIT's Project MAC. They took the name from Maxwell's demon, an imaginary being from a thought experiment that constantly works in the background, sorting molecules.[2]Unix systems inherited this terminology. Maxwell's demon is consistent with Greek mythology's interpretation of a daemon as a supernatural being working in the background, with no particular bias towards good or evil. However, BSD and some of its derivatives have adopted a Christian demon as their mascot rather than a Greek daemon.[citation needed]
The word daemon is an alternative spelling of demon,[3] and is pronounced /ˈdiːmən/DEE-mən. In the context of computer software, the original pronunciation /ˈdiːmən/ has drifted to /ˈdeɪmən/DAY-mən for some speakers.[1]
Alternative terms for daemon are service (used in Windows, from Windows NT onwards — and later also in Linux), started task (IBM z/OS),[4] and ghost job (XDS UTS).
After the term was adopted for computer use, it was rationalized as a 'backronym' for Disk And Execution MONitor.[5]
Daemons that connect to a computer network are examples of network services.
Implementations[edit]
Unix-like systems[edit]
In a strictly technical sense, a Unix-like system process is a daemon when its parent process terminates and the daemon is assigned the init process (process number 1) as its parent process and has no controlling terminal. However, more generally, a daemon may be any background process, whether a child of the init process or not.
On a Unix-like system, the common method for a process to become a daemon, when the process is started from the command line or from a startup script such as an init script or a SystemStarter script, involves:
![Show Show](/uploads/1/3/4/1/134186821/281646058.jpg)
- Optionally removing unnecessary variables from environment.
- Executing as a background task by forking and exiting (in the parent 'half' of the fork). This allows daemon's parent (shell or startup process) to receive exit notification and continue its normal execution.
- Detaching from the invoking session, usually accomplished by a single operation,
setsid()
:- Dissociating from the controlling tty.
- Creating a new session and becoming the session leader of that session.
- Becoming a process group leader.
- If the daemon wants to ensure that it won't acquire a new controlling tty even by accident (which happens when a session leader without a controlling tty opens a free tty), it may fork and exit again. This means that it is no longer a session leader in the new session, and can't acquire a controlling tty.
- Setting the root directory (/) as the current working directory so that the process does not keep any directory in use that may be on a mounted file system (allowing it to be unmounted).
- Changing the umask to 0 to allow
open()
,creat()
, and other operating system calls to provide their own permission masks and not to depend on the umask of the caller. - Redirecting file descriptors 0, 1 and 2 for the standard streams (stdin, stdout and stderr) to /dev/null or a logfile, and closing all the other file descriptors inherited from the parent process.
If the process is started by a super-server daemon, such as inetd, launchd, or systemd, the super-server daemon will perform those functions for the process,[6][7][8] except for old-style daemons not converted to run under systemd and specified as Type=Forking[8] and 'multi-threaded' datagram servers under inetd.[6]
MS-DOS[edit]
In the Microsoft DOS environment, daemon-like programs were implemented as terminate and stay resident (TSR) software.
Windows NT[edit]
On Microsoft Windows NT systems, programs called Windows services perform the functions of daemons. They run as processes, usually do not interact with the monitor, keyboard, and mouse, and may be launched by the operating system at boot time. In Windows 2000 and later versions, Windows services are configured and manually started and stopped using the Control Panel, a dedicated control/configuration program, the Service Controller component of the Service Control Manager (sc command), the net start and net stop commands or the PowerShell scripting system.
However, any Windows application can perform the role of a daemon, not just a service, and some Windows daemons have the option of running as a normal process.
Classic Mac OS and macOS[edit]
On the classic Mac OS, optional features and services were provided by files loaded at startup time that patched the operating system; these were known as system extensions and control panels. Later versions of classic Mac OS augmented these with fully fledged faceless background applications: regular applications that ran in the background. To the user, these were still described as regular system extensions.
macOS, which is a Unix system, uses daemons. Note that macOS uses the term 'services' to designate software that performs functions selected from the Services menu, rather than using that term for daemons as Windows does.
Etymology[edit]
According to Fernando J. Massive vst free download rar. Corbató, who worked on Project MAC in 1963, his team was the first to use the term daemon, inspired by Maxwell's demon, an imaginary agent in physics and thermodynamics that helped to sort molecules, stating, 'We fancifully began to use the word daemon to describe background processes that worked tirelessly to perform system chores'.[9]
In the general sense, daemon is an older form of the word 'demon', from the Greek δαίμων. In the Unix System Administration HandbookEvi Nemeth states the following about daemons:[10]
Many people equate the word 'daemon' with the word 'demon', implying some kind of satanic connection between UNIX and the underworld. This is an egregious misunderstanding. 'Daemon' is actually a much older form of 'demon'; daemons have no particular bias towards good or evil, but rather serve to help define a person's character or personality. The ancient Greeks' concept of a 'personal daemon' was similar to the modern concept of a 'guardian angel'--eudaemonia is the state of being helped or protected by a kindly spirit. As a rule, UNIX systems seem to be infested with both daemons and demons.
A further characterization of the mythological symbolism is that a daemon is something that is not visible yet is always present and working its will. In the Theages, attributed to Plato, Socrates describes his own personal daemon to be something like the modern concept of a moral conscience: 'The favour of the gods has given me a marvelous gift, which has never left me since my childhood. It is a voice that, when it makes itself heard, deters me from what I am about to do and never urges me on'.[citation needed]
See also[edit]
- Bounce message (also known as mailer daemon)
References[edit]
- ^ abEric S. Raymond. 'daemon'. The Jargon File. Retrieved 2008-10-22.
- ^Fernando J. Corbató (2002-01-23). 'Take Our Word for It'. Retrieved 2006-08-20.
- ^'Merriam-Webster definition of daemon'. Merriam-Webster Online. Retrieved 2009-08-05.
- ^'IBM Knowledge Center - Glossary of z/OS terms and abbreviations'. IBM.
- ^'Daemon Definition'. www.linfo.org.
- ^ ab
inetd(8)
– FreeBSD System Manager's Manual - ^
launchd.plist(5)
– Darwin and macOS File Formats Manual - ^ ab'systemd.service'. freedesktop.org. Retrieved August 25, 2012.
- ^'The Origin of the word Daemon'.
- ^'The BSD Daemon'. Freebsd.org. Retrieved 2008-11-15.
External links[edit]
Show Apps Running In Background
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