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Foundation Framework Reference NSProcessInfo Class Reference

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NSProcessInfo

Inheritance


Conforms To


Import Statement


Swift

import Foundation

Objective-C

@import Foundation;

Availability


Available in OS X v10.0 and later.

The NSProcessInfo class provides methods to access information about the current process. Each process has a single, shared NSProcessInfo object, known as process information agent.

The process information agent can return such information as the arguments, environment variables, host name, or process name. The processInfo class method returns the shared agent for the current process—that is, the process whose object sent the message. For example, the following line returns the NSProcessInfo object, which then provides the name of the current process:

  • NSString *processName = [[NSProcessInfo processInfo] processName];

The NSProcessInfo class also includes the operatingSystem method, which returns an enum constant identifying the operating system on which the process is executing.

NSProcessInfo objects attempt to interpret environment variables and command-line arguments in the user's default C string encoding if they cannot be converted to Unicode as UTF-8 strings. If neither conversion works, these values are ignored by the NSProcessInfo object.

Managing Activities

The system has heuristics to improve battery life, performance, and responsiveness of applications for the benefit of the user. You can use the following methods to manage activities that give hints to the system that your application has special requirements:

In response to creating an activity, the system will disable some or all of the heuristics so your application can finish quickly while still providing responsive behavior if the user needs it.

You use activities when your application is performing a long-running operation. If the activity can take different amounts of time (for example, calculating the next move in a chess game), it should use this API. This will ensure correct behavior when the amount of data or the capabilities of the user's computer varies. You should put your activity into one of two major categories:

  1. User initiated: These are finite length activities that the user has explicitly started. Examples include exporting or downloading a user specified file.

  2. Background: These are finite length activities that are part of the normal operation of your application but are not explicitly started by the user. Examples include autosaving, indexing, and automatic downloading of files.

In addition, if your application requires high priority I/O, you can include the NSActivityLatencyCritical flag (using a bitwise OR). You should only use this flag for activities like audio or video recording that really do require high priority.

If your activity takes place synchronously inside an event callback on the main thread, you do not need to use this API.

Be aware that failing to end these activities for an extended period of time can have significant negative impacts to the performance of your user's computer, so be sure to use only the minimum amount of time required. User preferences may override your application’s request.

You can also use this API to control automatic termination or sudden termination (see Sudden Termination). For example:

  • id activity = [[NSProcessInfo processInfo] beginActivityWithOptions:NSActivityAutomaticTerminationDisabled reason:@"Good Reason"];
  • // Perform some work.
  • [[NSProcessInfo processInfo] endActivity:activity];

is equivalent to:

  • [[NSProcessInfo processInfo] disableAutomaticTermination:@"Good Reason"];
  • // Perform some work.
  • [[NSProcessInfo processInfo] enableAutomaticTermination:@"Good Reason"];

Because this API returns an object, it may be easier to pair begins and ends than when using the automatic termination API—if the object is deallocated before the endActivity: call, the activity will be automatically ended.

This API also provides a mechanism to disable system-wide idle sleep and display idle sleep. These can have a large impact on the user experience, so be sure not to forget to end activities that disable sleep (including NSActivityUserInitiated).

Sudden Termination

OS X v10.6 and later includes a mechanism that allows the system to log out or shut down more quickly by, whenever possible, killing applications instead of requesting that they quit themselves.

Your application can enable this capability on a global basis and then manually override its availability during actions that could cause data corruption or a poor user experience by allowing sudden termination. Alternately, your application can just manually enable and disable this functionality.

The methods enableSuddenTermination and disableSuddenTermination decrement or increment, respectively, a counter whose value is 1 when the process is first created. When the counter's value is 0 the application is considered to be safely killable and may be killed by the system without any notification or event being sent to the process first.

Your application can support sudden termination upon launch by adding a key to the application’s Info.plist. If the NSSupportsSuddenTermination key exists in the Info.plist and has a value of YEStrue, it is the equivalent of calling enableSuddenTermination during your application launch. This renders the application process killable right away. You can still override this behavior by invoking disableSuddenTermination.

Typically, you disable sudden termination whenever your application defers work that must be done before the application terminates. If, for example, your application defers writing data to disk, and sudden termination is enabled, you should bracket the sensitive operations with a call to disableSuddenTermination, perform the necessary operations, and then send a balancing enableSuddenTermination message.

In agents or daemon executables that don't depend on AppKit you can manually invoke enableSuddenTermination right away. You can then use the enable and disable methods whenever the process has work it must do before it terminates.

Some AppKit functionality automatically disables sudden termination on a temporary basis to ensure data integrity.

  • NSUserDefaults temporarily disables sudden termination to prevent process killing between the time at which a default has been set and the time at which the preferences file including that default has been written to disk.

  • NSDocument temporarily disables sudden termination to prevent process killing between the time at which the user has made a change to a document and the time at which the user's change has been written to disk.

Thermal State and App Performance

Use the current thermal state to determine if your app should reduce system usage. On OS X v10.10.3 and later you can register for the NSProcessInfoThermalStateDidChangeNotification to be notified when the thermal state changes. Use thermalState to query the current state. Your app should reduce system usage at higher thermal states. For recommended actions, see NSProcessInfoThermalState.

  • Returns the process information agent for the process.

    Declaration

    Swift

    class func processInfo() -> NSProcessInfo

    Objective-C

    + (NSProcessInfo *)processInfo

    Return Value

    Shared process information agent for the process.

    Discussion

    An NSProcessInfo object is created the first time this method is invoked, and that same object is returned on each subsequent invocation.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

  • arguments arguments Property

    Array of strings with the command-line arguments for the process.

    Declaration

    Swift

    var arguments: [AnyObject] { get }

    Objective-C

    @property(readonly, copy) NSArray *arguments

    Discussion

    This array contains all the information passed in the argv array, including the executable name in the first element.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

  • The variable names (keys) and their values in the environment from which the process was launched.

    Declaration

    Swift

    var environment: [NSObject : AnyObject] { get }

    Objective-C

    @property(readonly, copy) NSDictionary *environment

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

  • Global unique identifier for the process. (read-only)

    Declaration

    Swift

    var globallyUniqueString: String { get }

    Objective-C

    @property(readonly, copy) NSString *globallyUniqueString

    Discussion

    The global ID for the process includes the host name, process ID, and a time stamp, which ensures that the ID is unique for the network. This property generates a new string each time its getter is invoked, and it uses a counter to guarantee that strings created from the same process are unique.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

    See Also

    processName

  • The identifier of the process (often called process ID).

    Declaration

    Swift

    var processIdentifier: Int32 { get }

    Objective-C

    @property(readonly) int processIdentifier

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

    See Also

    processName

  • The name of the process.

    Declaration

    Swift

    var processName: String

    Objective-C

    @property(copy) NSString *processName

    Discussion

    The process name is used to register application defaults and is used in error messages. It does not uniquely identify the process.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

  • Disables the application for quickly killing using sudden termination.

    Declaration

    Swift

    func disableSuddenTermination()

    Objective-C

    - (void)disableSuddenTermination

    Discussion

    This method increments the sudden termination counter. When the termination counter reaches 0 the application allows sudden termination.

    By default the sudden termination counter is set to 1. This can be overridden in your application Info.plist. See Sudden Termination for more information and debugging suggestions.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.6 and later.

  • Enables the application for quick killing using sudden termination.

    Declaration

    Swift

    func enableSuddenTermination()

    Objective-C

    - (void)enableSuddenTermination

    Discussion

    This method decrements the sudden termination counter. When the termination counter reaches 0 the application allows sudden termination.

    By default the sudden termination counter is set to 1. This can be overridden in your application Info.plist. See Sudden Termination for more information and debugging suggestions.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.6 and later.

  • Disables automatic termination for the application.

    Declaration

    Swift

    func disableAutomaticTermination(_ reason: String)

    Objective-C

    - (void)disableAutomaticTermination:(NSString *)reason

    Parameters

    reason

    The reason why automatic termination is being disabled.

    Discussion

    This method increments the automatic termination counter. When the counter is greater than 0, the application is considered active and ineligible for automatic termination. For example, you could disable automatic termination when the user of an instant messaging application signs on, because the application requires a background connection to be maintained even if the application is otherwise inactive.

    The reason parameter is used to track why an application is or is not automatically terminable and can be inspected by debugging tools. For example, you could pass the string @"file transfer in progress" if you disable automatic termination before transferring a file over the network. When you reenable automatic termination after the transfer is complete using enableAutomaticTermination:, you should pass the matching string. A given reason can be used more than once at the same time; for example, if two files were being transferred at the same time, automatic termination could be disabled for each, passing the same reason string.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.7 and later.

  • Enables automatic termination for the application.

    Declaration

    Swift

    func enableAutomaticTermination(_ reason: String)

    Objective-C

    - (void)enableAutomaticTermination:(NSString *)reason

    Parameters

    reason

    The reason why automatic termination is being enabled.

    Discussion

    This method decrements the automatic termination counter. When the counter is 0, the application is eligible for automatic termination.

    The reason parameter is used to track why an application is or is not automatically terminable and can be inspected by debugging tools. For example, you could pass the string @"file transfer in progress" if you disable automatic termination before transferring a file over the network. When you reenable automatic termination after the transfer is complete using enableAutomaticTermination:, you should pass the matching string. A given reason can be used more than once at the same time; for example, if two files were being transferred at the same time, automatic termination could be disabled for each, passing the same reason string.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.7 and later.

  • A Boolean value indicating whether the app supports automatic termination.

    Declaration

    Swift

    var automaticTerminationSupportEnabled: Bool

    Objective-C

    @property BOOL automaticTerminationSupportEnabled

    Discussion

    Without setting this property or setting the equivalent Info.plist key (NSSupportsAutomaticTermination), the methods disableAutomaticTermination: and enableAutomaticTermination: have no effect, although the counter tracking automatic termination opt-outs is still kept up to date to ensure correctness if this is called later. Currently, setting this property to NOfalse has no effect. This property should be set in the app delegate method applicationDidFinishLaunching: or earlier.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.7 and later.

  • hostName hostName Property

    The name of the host computer on which the process is executing. (read-only)

    Declaration

    Swift

    var hostName: String { get }

    Objective-C

    @property(readonly, copy) NSString *hostName

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

  • Returns a constant to indicate the operating system on which the process is executing.

    Deprecation Statement

    Use operatingSystemVersion or isOperatingSystemAtLeastVersion: instead

    Declaration

    Swift

    func operatingSystem() -> Int

    Objective-C

    - (NSUInteger)operatingSystem

    Return Value

    Operating system identifier. See Constants for a list of possible values. In OS X, it’s NSMACHOperatingSystem.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

    Deprecated in OS X v10.10.

  • Returns a string containing the name of the operating system on which the process is executing.

    Deprecation Statement

    Use operatingSystemVersionString instead.

    Declaration

    Swift

    func operatingSystemName() -> String

    Objective-C

    - (NSString *)operatingSystemName

    Return Value

    Operating system name. In OS X, it’s @"NSMACHOperatingSystem"

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.0 and later.

    Deprecated in OS X v10.10.

  • A string containing the version of the operating system on which the process is executing. (read-only)

    Declaration

    Swift

    var operatingSystemVersionString: String { get }

    Objective-C

    @property(readonly, copy) NSString *operatingSystemVersionString

    Discussion

    The operating system version string is human readable, localized, and is appropriate for displaying to the user. This string is not appropriate for parsing.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.2 and later.

  • The version of the operating system on which the process is executing. (read-only)

    Declaration

    Swift

    var operatingSystemVersion: NSOperatingSystemVersion { get }

    Objective-C

    @property(readonly) NSOperatingSystemVersion operatingSystemVersion

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.10 and later.

  • Returns a Boolean value indicating whether the version of the operating system on which the process is executing is the same or later than the given version.

    Declaration

    Swift

    func isOperatingSystemAtLeastVersion(_ version: NSOperatingSystemVersion) -> Bool

    Objective-C

    - (BOOL)isOperatingSystemAtLeastVersion:(NSOperatingSystemVersion)version

    Parameters

    version

    The operating system version to test against.

    Return Value

    YEStrue if the operating system on which the process is executing is the same or later than the given version; otherwise NOfalse.

    Discussion

    This method accounts for major, minor, and update versions of the operating system.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.10 and later.

  • The number of processing cores available on the computer. (read-only)

    Declaration

    Swift

    var processorCount: Int { get }

    Objective-C

    @property(readonly) NSUInteger processorCount

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.5 and later.

  • The number of active processing cores available on the computer. (read-only)

    Declaration

    Swift

    var activeProcessorCount: Int { get }

    Objective-C

    @property(readonly) NSUInteger activeProcessorCount

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.5 and later.

    See Also

    processorCount

  • The amount of physical memory on the computer in bytes. (read-only)

    Declaration

    Swift

    var physicalMemory: UInt64 { get }

    Objective-C

    @property(readonly) unsigned long long physicalMemory

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.5 and later.

  • The time interval since the computer was restarted. (read-only)

    Declaration

    Swift

    var systemUptime: NSTimeInterval { get }

    Objective-C

    @property(readonly) NSTimeInterval systemUptime

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.6 and later.

  • The current thermal state of the system. (read-only)

    Declaration

    Swift

    var thermalState: NSProcessInfoThermalState { get }

    Objective-C

    @property(readonly) NSProcessInfoThermalState thermalState

    Discussion

    Returns a NSProcessInfoThermalState with the current thermal state of the system. At higher thermal states your app should reduce usage of system resources. For more information, see NSProcessInfoThermalState.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.10.3 and later.

Data Types

  • Operating system version structure used with operatingSystemVersion and isOperatingSystemAtLeastVersion:.

    Declaration

    Swift

    struct NSOperatingSystemVersion { var majorVersion: Int var minorVersion: Int var patchVersion: Int init() init(majorVersion majorVersion: Int, minorVersion minorVersion: Int, patchVersion patchVersion: Int) }

    Objective-C

    typedef struct { NSInteger majorVersion; NSInteger minorVersion; NSInteger patchVersion; } NSOperatingSystemVersion;

    Constants

    • majorVersion

      majorVersion

      The major release number, such as 10 in version 10.9.3.

    • minorVersion

      minorVersion

      The minor release number, such as 9 in version 10.9.3.

    • patchVersion

      patchVersion

      The update release number, such as 3 in version 10.9.3.

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.10 and later.

  • Declaration

    Swift

    struct NSActivityOptions : RawOptionSetType { init(_ rawValue: UInt64) init(rawValue rawValue: UInt64) static var IdleDisplaySleepDisabled: NSActivityOptions { get } static var IdleSystemSleepDisabled: NSActivityOptions { get } static var SuddenTerminationDisabled: NSActivityOptions { get } static var AutomaticTerminationDisabled: NSActivityOptions { get } static var UserInitiated: NSActivityOptions { get } static var UserInitiatedAllowingIdleSystemSleep: NSActivityOptions { get } static var Background: NSActivityOptions { get } static var LatencyCritical: NSActivityOptions { get } }

    Objective-C

    typedef enum : uint64_t { NSActivityIdleDisplaySleepDisabled = (1ULL << 40), NSActivityIdleSystemSleepDisabled = (1ULL << 20), NSActivitySuddenTerminationDisabled = (1ULL << 14), NSActivityAutomaticTerminationDisabled = (1ULL << 15), NSActivityUserInitiated = (0x00FFFFFFULL | NSActivityIdleSystemSleepDisabled ), NSActivityUserInitiatedAllowingIdleSystemSleep = (NSActivityUserInitiated & ~NSActivityIdleSystemSleepDisabled ), NSActivityBackground = 0x000000FFULL, NSActivityLatencyCritical = 0xFF00000000ULL, } NSActivityOptions;

    Constants

    • IdleDisplaySleepDisabled

      NSActivityIdleDisplaySleepDisabled

      Flag to require the screen to stay powered on.

      Available in OS X v10.9 and later.

    • IdleSystemSleepDisabled

      NSActivityIdleSystemSleepDisabled

      Flag to prevent idle sleep.

      This is included in NSActivityUserInitiatedAllowingIdleSystemSleep.

      Available in OS X v10.9 and later.

    • SuddenTerminationDisabled

      NSActivitySuddenTerminationDisabled

      Flag to prevent sudden termination.

      This is included in NSActivityUserInitiatedAllowingIdleSystemSleep.

      Available in OS X v10.9 and later.

    • AutomaticTerminationDisabled

      NSActivityAutomaticTerminationDisabled

      Flag to prevent automatic termination.

      This is included in NSActivityUserInitiatedAllowingIdleSystemSleep.

      Available in OS X v10.9 and later.

    • UserInitiated

      NSActivityUserInitiated

      Flag to indicate the app is performing a user-requested action.

      Available in OS X v10.9 and later.

    • UserInitiatedAllowingIdleSystemSleep

      NSActivityUserInitiatedAllowingIdleSystemSleep

      Flag to indicate the app is performing a user-requested action, but that the system can sleep on idle.

      Available in OS X v10.9 and later.

    • Background

      NSActivityBackground

      Flag to indicate the app has initiated some kind of work, but not as the direct result of user request.

      Available in OS X v10.9 and later.

    • LatencyCritical

      NSActivityLatencyCritical

      Flag to indicate the activity requires the highest amount of timer and I/O precision available.

      Available in OS X v10.9 and later.

    Discussion

    To include one of these individual flags in one of the sets, use bitwise OR; for example, during a presentation you might use:

    • NSActivityUserInitiated | NSActivityIdleDisplaySleepDisabled

    To exclude from one of the sets, use bitwise AND with NOT; for example, during a user initiated action that may be safely terminated with no application interaction in case of logout you might use:

    • NSActivityUserInitiated & ~NSActivitySuddenTerminationDisabled

    Import Statement

    Objective-C

    @import Foundation;

    Swift

    import Foundation

    Availability

    Available in OS X v10.9 and later.

  • The following constants are provided by the NSProcessInfo class as return values for thermalState.

    Declaration

    Swift

    enum NSProcessInfoThermalState : Int { case Nominal case Fair case Serious case Critical }

    Objective-C

    enum { NSProcessInfoThermalStateNominal, NSProcessInfoThermalStateFair, NSProcessInfoThermalStateSerious, NSProcessInfoThermalStateCritical };

    Constants

    • Nominal

      NSProcessInfoThermalStateNominal

      The thermal state is within normal limits and no corrective action is needed.

      Available in OS X v10.10.3 and later.

    • Fair

      NSProcessInfoThermalStateFair

      The thermal state is slightly elevated, fans may be audible.

      Available in OS X v10.10.3 and later.

    • Serious

      NSProcessInfoThermalStateSerious

      The thermal state is high. Fans are running at maximum speed and system performance may be impacted. The app should reduce usage of the CPU, GPU, and any I/O such as networking or bluetooth.

      Available in OS X v10.10.3 and later.

    • Critical

      NSProcessInfoThermalStateCritical

      The thermal state is significantly impacting the performance of the system and the device needs to cool down. The app should reduce usage of the CPU, GPU, and any I/O to the minimum level required for user interaction. It is recommended that the app stop using peripherals such as the camera.

      Available in OS X v10.10.3 and later.

  • The following constants are provided by the NSProcessInfo class as return values for operatingSystem.

    Declaration

    Swift

    var NSHPUXOperatingSystem: Int { get } var NSMACHOperatingSystem: Int { get } var NSOSF1OperatingSystem: Int { get } var NSSolarisOperatingSystem: Int { get } var NSSunOSOperatingSystem: Int { get } var NSWindows95OperatingSystem: Int { get } var NSWindowsNTOperatingSystem: Int { get }

    Objective-C

    enum { NSWindowsNTOperatingSystem = 1, NSWindows95OperatingSystem, NSSolarisOperatingSystem, NSHPUXOperatingSystem, NSMACHOperatingSystem, NSSunOSOperatingSystem, NSOSF1OperatingSystem };

    Constants

    • NSHPUXOperatingSystem

      NSHPUXOperatingSystem

      Indicates the HP UX operating system.

      Available in OS X v10.0 and later.

      Deprecated in OS X v10.10.

    • NSMACHOperatingSystem

      NSMACHOperatingSystem

      Indicates the OS X operating system.

      Available in OS X v10.0 and later.

      Deprecated in OS X v10.10.

    • NSOSF1OperatingSystem

      NSOSF1OperatingSystem

      Indicates the OSF/1 operating system.

      Available in OS X v10.0 and later.

      Deprecated in OS X v10.10.

    • NSSolarisOperatingSystem

      NSSolarisOperatingSystem

      Indicates the Solaris operating system.

      Available in OS X v10.0 and later.

      Deprecated in OS X v10.10.

    • NSSunOSOperatingSystem

      NSSunOSOperatingSystem

      Indicates the Sun OS operating system.

      Available in OS X v10.0 and later.

      Deprecated in OS X v10.10.

    • NSWindows95OperatingSystem

      NSWindows95OperatingSystem

      Indicates the Windows 95 operating system.

      Available in OS X v10.0 and later.

      Deprecated in OS X v10.10.

    • NSWindowsNTOperatingSystem

      NSWindowsNTOperatingSystem

      Indicates the Windows NT operating system.

      Available in OS X v10.0 and later.

      Deprecated in OS X v10.10.