StackOverflow2013

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copied!<p><strong>Q1:</strong></p> <p>No. <code>@synthesize</code> does not modify the <code>-dealloc</code> for you. You have to <code>-release</code> the <code>name</code> yourself.</p> <p><strong>Q2:</strong></p> <p>Yes it will leak. Same reason as Q1.</p> <p><strong>Q3:</strong></p> <p>No it won't double-release. Same reason as Q1.</p> <p><strong>Q4:</strong></p> <p>Yes it will leak. Same reason as Q1.</p> <p><strong>Q5:</strong></p> <p>No it won't double-release. Same reason as Q1.</p> <hr> <p>You can check this yourself by overriding <code>-retain</code> and <code>-release</code> and <code>-dealloc</code> to report what is going on.</p> <pre><code>#import <Foundation/Foundation.h> @interface X : NSObject {} @end @implementation X -(oneway void)release { NSLog(@"Releasing %p, next count = %d", self, [self retainCount]-1); [super release]; } -(id)retain { NSLog(@"Retaining %p, next count = %d", self, [self retainCount]+1); return [super retain]; } -(void)dealloc { NSLog(@"Dealloc %p", self); [super dealloc]; } @end @interface Y : NSObject { X* x; } @property (nonatomic, retain) X* x; @end @implementation Y @synthesize x; - (void)dealloc { [x release]; [super dealloc]; } @end int main () { NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init]; Y* y = [[Y alloc] init]; X* x = [[X alloc] init]; y.x = x; [y release]; [x release]; [pool drain]; return 0; } </code></pre> <p>In Q1, Q2 and Q4, the last <code>-retainCount</code> of <code>x</code> is 1, so there is a leak, and in Q3 and Q5 the last <code>-retainCount</code> is 0 and <code>-dealloc</code> is called, so there is no leak.</p>

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