MemoryMgmt.pdf

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Memory Management Programming Guide
MemoryManagementProgrammingGuide
Performance
2011-03-24
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Contents
AboutMemoryManagement 7
AtaGlance 7
GoodPracticesPreventMemory-RelatedProblems 8
UseAnalysisToolstoDebugMemoryProblems 8
MemoryManagementPolicy 11
BasicMemoryManagementRules 11
ASimpleExample 11
UseautoreleasetoSendaDeferredrelease 12
YouDon’tOwnObjectsReturnedbyReference 13
ImplementdealloctoRelinquishOwnershipofObjects 13
CoreFoundationUsesSimilarbutDifferentRules 14
PracticalMemoryManagement 15
UseAccessorMethodstoMakeMemoryManagementEasier 15
UseAccessorMethodstoSetPropertyValues 16
Don’tUseAccessorMethodsinInitializerMethodsanddealloc 16
UseWeakReferencestoAvoidRetainCycles 17
AvoidCausingDeallocationofObjectsYou’reUsing 18
Don’tUsedealloctoManageScarceResources 19
CollectionsOwntheObjectsTheyContain 20
OwnershipPolicyIsImplementedUsingRetainCounts 20
UsingAutoreleasePools 23
AboutAutoreleasePools 23
UseLocalAutoreleasePoolstoReducePeakMemoryFootprint 24
AutoreleasePoolsandThreads 25
ScopeofAutoreleasePoolsandImplicationsofNestedAutoreleasePools 25
GarbageCollection 26
DocumentRevisionHistory 27
2011-03-24 | © 2011 Apple Inc. All Rights Reserved.
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2011-03-24 | © 2011 Apple Inc. All Rights Reserved.
Figures
PracticalMemoryManagement 15
Figure1 Anillustrationofcyclicalreferences 17
2011-03-24 | © 2011 Apple Inc. All Rights Reserved.
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