2008-04 Pointers

8/14/2019 2008-04 Pointers

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Selected Topics in Computer Programming #2

Selected Topics in Computer Programming #2Selected Topics in Computer Programming #2

Fine Points of C++ Pointers:Pointers:

Dumb, Smart, and SmarterDumb, Smart, and Smarter

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Quick review of pointer nomenclatureQuick review of pointer nomenclature

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The pointerThe pointer--pointee relationshippointee relationship

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http://xkcd.com/c138.htmlhttp://xkcd.com/c138.html

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Other C++ pointerOther C++ pointer--like entitieslike entities

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C++ pointer useC++ pointer use

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A few more pointerA few more pointer--related remindersrelated reminders

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Some pointer behaviors are undefinedSome pointer behaviors are undefined

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Lifetime of C++ variablesLifetime of C++ variables

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C++ dynamicC++ dynamic lifetimelifetime management involves pointersmanagement involves pointers

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But using pointers is problematicalBut using pointers is problematical [Koenig/Moo, 2000][Koenig/Moo, 2000]

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Pointer issues 1: initializationPointer issues 1: initialization

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Pointer issues 2: copyingPointer issues 2: copying

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Pointer issues 3: pointer destructionPointer issues 3: pointer destruction

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Two common pointer misunderstandingsTwo common pointer misunderstandings

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http://xkcd.com/371http://xkcd.com/371

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The moral of the storyThe moral of the story

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The resourceThe resource management patternmanagement pattern

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Issues in releasing resourcesIssues in releasing resources

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Some realities of resource managementSome realities of resource management

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But resourceBut resource management algorithms are separablemanagement algorithms are separable

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Characteristics of handlesCharacteristics of handles

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The RAII patternThe RAII pattern

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Recommended best practiceRecommended best practice

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But anonymous handles carry risksBut anonymous handles carry risks

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PHLPHL ’’s conversions can be problematics conversions can be problematic

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More standard handles are on the way (C++0X)More standard handles are on the way (C++0X)

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Advantages of the pimpl patternAdvantages of the pimpl pattern

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Other handleOther handle--based programming patternsbased programming patterns

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Preventing clients from deleting pointeesPreventing clients from deleting pointees

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Pointing to a staticPointing to a static--lifetime objectlifetime object

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Executing cleanup code on block exitExecuting cleanup code on block exit

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Dealing with legacy codeDealing with legacy code

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InIn sumsum

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2008-04 Pointers