In object-oriented programming (OOP), object lifetime is the period of time between an object's creation and its destruction. In some programming contexts, object lifetime coincides with the lifetime of a variable that represents the object. In other contexts – where the object is accessed by reference – object lifetime is not determined by the lifetime of a variable. For example, destruction of the variable may only destroy the reference; not the referenced object.
29-642: [REDACTED] Look up lifetime in Wiktionary, the free dictionary. Lifetime may refer to: The period between one's birth and death Life expectancy , the length of time a person is expected to remain alive Arts, entertainment, and media [ edit ] Music [ edit ] Lifetime (band) , a melodic hardcore band from New Jersey Life Time (Rollins Band album) , by Rollins Band Life Time (Tony Williams album) , by American jazz drummer Tony Williams Lifetime (Lifetime album) ,
58-445: A finalizer before memory deallocation. Destroying an object will cause any references to the object to become invalid. With manual memory management, any existing reference becomes a dangling reference . With garbage collection, objects are only destroyed when there are no references to them. Object lifetime begins when allocation completes and ends when deallocation starts. Thus, during initialization and finalization, an object
87-518: A constructor handles initialization. Like other methods, a constructor can be overloaded in order to support creating with different initial state. Generally, an object is removed from memory after it is no longer needed. However, if there is sufficient memory or a program has a short run time, object destruction may not occur; memory simply being deallocated at process termination. In some cases, object destruction consists solely of deallocating memory, particularly with garbage-collection, or if
116-434: A destructor is called when an instance is deleted, before the memory is deallocated. In C++, destructors differ from constructors in various ways. They cannot be overloaded, must have no arguments, need not maintain class invariants , and can cause program termination if they throw exceptions. With garbage collection , objects may be destroyed when they can no longer be accessed by the program. The garbage-collector calls
145-408: A melodic hardcore band from New Jersey Life Time (Rollins Band album) , by Rollins Band Life Time (Tony Williams album) , by American jazz drummer Tony Williams Lifetime (Lifetime album) , a 2007 album by the band Lifetime Lifetime (Real Life album) , 1990 Lifetime (Klein album) , 2019 LifeTimes , a 1979 album by Diana Hubbard "Lifetime" (Katharine McPhee song) ,
174-431: A 1994 Chinese film, also known as To Live Lifetimes: True Accounts of Reincarnation (1979), a book by Frederick Lenz Lifetimes , alternate English title for the 1994 Chinese film To Live Duration or time span [ edit ] Mean lifetime , a certain number that characterizes the rate of reduction ("decay") of an assembly of unstable particles Object lifetime , in object-oriented programming,
203-431: A 1994 Chinese film, also known as To Live Lifetimes: True Accounts of Reincarnation (1979), a book by Frederick Lenz Lifetimes , alternate English title for the 1994 Chinese film To Live Duration or time span [ edit ] Mean lifetime , a certain number that characterizes the rate of reduction ("decay") of an assembly of unstable particles Object lifetime , in object-oriented programming,
232-501: A 2001 song by Better Than Ezra Life span (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Lifetime . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Lifetime&oldid=1246701219 " Category : Disambiguation pages Hidden categories: Short description
261-501: A 2001 song by Better Than Ezra Life span (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Lifetime . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Lifetime&oldid=1246701219 " Category : Disambiguation pages Hidden categories: Short description
290-465: A 2001 track by Slam "Lifetimes", a 2005 song by Sheryl Crow from Wildflower Television [ edit ] "Life Time" ( M*A*S*H ) , a 1979 episode of the TV series M*A*S*H Lifetime (Southeast Asian TV channel) , an Asian television channel owned by A+E Networks Asia Lifetime (TV network) , a cable television programming network geared towards women Lifetime (Canadian TV channel) ,
319-536: A 2007 album by the band Lifetime Lifetime (Real Life album) , 1990 Lifetime (Klein album) , 2019 LifeTimes , a 1979 album by Diana Hubbard "Lifetime" (Katharine McPhee song) , a 2010 song from Unbroken "Lifetime" (Noah and the Whale song) "Lifetime" (Maxwell song) , a 2002 song by American R&B singer Maxwell "Lifetime" (Swedish House Mafia song) "Lifetime" (Three Days Grace song) "Lifetime" (Usher song) "Lifetimes" (song) ,
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#1732773281481348-511: A 2010 song from Unbroken "Lifetime" (Noah and the Whale song) "Lifetime" (Maxwell song) , a 2002 song by American R&B singer Maxwell "Lifetime" (Swedish House Mafia song) "Lifetime" (Three Days Grace song) "Lifetime" (Usher song) "Lifetimes" (song) , a 2024 song by Katy Perry from 143 "Lifetime", a 2009 song by Kris Allen from Kris Allen "Lifetime", a 2021 song by Justin Bieber from Justice "Lifetimes",
377-492: A 2024 song by Katy Perry from 143 "Lifetime", a 2009 song by Kris Allen from Kris Allen "Lifetime", a 2021 song by Justin Bieber from Justice "Lifetimes", a 2001 track by Slam "Lifetimes", a 2005 song by Sheryl Crow from Wildflower Television [ edit ] "Life Time" ( M*A*S*H ) , a 1979 episode of the TV series M*A*S*H Lifetime (Southeast Asian TV channel) , an Asian television channel owned by A+E Networks Asia Lifetime (TV network) ,
406-644: A cable television programming network geared towards women Lifetime (Canadian TV channel) , the Canadian version of the TV channel of the same name Lifetime (British and Irish TV channel) , a defunct British entertainment television channel Lifetime Entertainment Services (LES), an American entertainment industry company LMN , formerly Lifetime Movie Network and Lifetime Movies, an American digital cable and satellite television network Other uses in arts, entertainment, and media [ edit ] Lifetimes , an alternative English-language title for
435-444: A constructor is a class method as there is no object (instance) available until the object is created, but destructors, initializers, and finalizers are instance methods. Further, constructors and initializers often can accept arguments, while destructors and finalizers generally do not as they are often implicitly callable. In languages with deterministic lifetime objects, lifetime may be used to piggyback resource management . This
464-416: Is alive, but may not be in a consistent state. The period between when initialization completes to when finalization starts is when the object is both alive and in a consistent state. If creation or destruction fail, error reporting (for example, raising an exception) can be complicated since the object or related objects may be in an inconsistent state. For a static variable , with lifespan coinciding with
493-499: Is called the Resource Acquisition Is Initialization (RAII) idiom. Resources are acquired during initialization, and released during finalization. In languages with non-deterministic lifetime objects (i.e. garbage collected), the management of memory is generally kept separate from management of other resources. A C++ class can be declared with defaults as: When declared in an automatic context,
522-423: Is destroyed via the delete keyword. In C# and Java, with no explicit destruction syntax, the garbage collector destroys unused objects automatically and non-deterministically. An alternative and deterministic approach to automatic destruction is where the object is destroyed when code decrements the object's reference count to zero. With an object pool , where objects may be created ahead of time and reused,
551-492: Is different from Wikidata All article disambiguation pages All disambiguation pages lifetime [REDACTED] Look up lifetime in Wiktionary, the free dictionary. Lifetime may refer to: The period between one's birth and death Life expectancy , the length of time a person is expected to remain alive Arts, entertainment, and media [ edit ] Music [ edit ] Lifetime (band) ,
580-498: Is different from Wikidata All article disambiguation pages All disambiguation pages Object lifetime Aspects of object lifetime vary between programming languages and within implementations of a language. The core concepts are relatively common, but terminology varies. For example, the concepts of create and destroy are sometimes termed construct and destruct and the language elements are termed constructor (ctor) and destructor (dtor). Creation of an object
609-494: Is generally deterministic , but destruction varies by programming context. Some contexts allow for deterministic destruction, but some do not. Notably, in a garbage-collection environment, objects are destroyed when the garbage collector chooses. The syntax for creation and destruction varies by programming context. In many contexts, including C++, C# and Java, an object is created via special syntax like new typename() . In C++, that provides manual memory management , an object
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#1732773281481638-490: The Canadian version of the TV channel of the same name Lifetime (British and Irish TV channel) , a defunct British entertainment television channel Lifetime Entertainment Services (LES), an American entertainment industry company LMN , formerly Lifetime Movie Network and Lifetime Movies, an American digital cable and satellite television network Other uses in arts, entertainment, and media [ edit ] Lifetimes , an alternative English-language title for
667-458: The apparent creation and destruction of an object may not correspond to actual. The pool provides reinitialization for creation and finalization for destruction. Both creation and destruction may be non-deterministic. Objects with static memory allocation have a lifetime that coincides with the run of a program, but the order of creation and destruction of the various static objects is generally non-deterministic. Object life cycle refers to
696-660: The events that an object experiences including and between creation and destruction. Life cycle generally includes memory management and operations after allocation and before deallocation. Object creation generally consists of memory allocation and initialization where initialization includes assigning values to fields and running initialization code. Object destruction generally consists of finalization (a.k.a. cleanup) and memory deallocation (a.k.a. free). These steps generally proceed in order as: allocate, initialize, finalize, deallocate. Based on programming context, these steps may be partially or fully automated, and some of
725-444: The object is a plain old data structure . In other cases, cleanup is performed prior to deallocation, particularly destroying member objects (in manual memory management), or deleting references from the object to other objects to decrement reference counts (in reference counting). This may be automatic, or a special destruction method may be called on the object. In class-based languages with deterministic object lifetime, notably C++,
754-406: The program run, a creation or destruction error is problematic since program execution is before or after normal execution. In class-based programming, object creation is also known as instantiation (creating an instance of a class ). Creation and destruction can be customized via a constructor and a destructor and sometimes with separate initializer and finalizer methods. Notably,
783-463: The steps can be customized. The frequency of customization tends to vary by step and programming context. Initialization is the most commonly customized step. Finalization is common in languages with deterministic destruction, notably C++, but rare in garbage-collected languages. Allocation is rarely customized, and deallocation generally cannot be customized. The way to create objects varies across programming contexts. In some class-based languages,
812-654: The time between an object's creation until the object is no longer used Product lifetime , a product's expected lifetime Service life , a product's expected time in use between point of sale and point of discard Enterprises and organizations [ edit ] Lifetimes, a museum in Croydon, England (1995–2004), now known as the Museum of Croydon Lifetime Products , a manufacturer of tables, chairs, outdoor sheds, utility trailers, and residential basketball equipment See also [ edit ] " A Lifetime ",
841-547: The time between an object's creation until the object is no longer used Product lifetime , a product's expected lifetime Service life , a product's expected time in use between point of sale and point of discard Enterprises and organizations [ edit ] Lifetimes, a museum in Croydon, England (1995–2004), now known as the Museum of Croydon Lifetime Products , a manufacturer of tables, chairs, outdoor sheds, utility trailers, and residential basketball equipment See also [ edit ] " A Lifetime ",
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