StackOverflow2013

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PO@property copy & manual memory management with an autorelease pool
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copied!<p>I have a class that copy's an NSString and print's it's retain count and address.</p> <pre><code>@interface TestStringPointer : NSObject @property (copy) NSString *stringTest; - (void)printPointer; @end @implementation TestStringPointer - (void)printPointer { NSLog(@"PrintPointer:%p\n RetainCount:%lu", _stringTest, [_stringTest retainCount]); } @end </code></pre> <p>In my main function I was doing a bit of investigation on the String's pointer and ran into an issue.</p> <pre><code>int main(int argc, const char * argv[]) { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; TestStringPointer *test = [[TestStringPointer alloc] init]; NSString *myString = [NSString stringWithUTF8String:"Hello World"]; NSLog(@"MyString: %p \n RetainCount:%lu", myString, [myString retainCount]); [test setStringTest:myString]; [test printPointer]; [myString release]; [pool drain]; while (1) { [test printPointer]; } return 0; } </code></pre> <p>When I debug the app it crashes the 3rd time through the while loop (the number of times through the loop varies). I understand that the copy doesn't occur cause the string isn't mutable. After it's released in main, I would've expected it to go back to 1. <br> 1) If an object isn't autoreleased, is it still affected the autorelease pool?<br> 2) Wouldn't having a max retain count prevent the object from being drained in the pool, or does that flag it for deletion?<br> 3) Shouldn't the copy have stepped in at some point and actually made a copy before it was deleted?</p> <blockquote> <p>StringPointerTest[2253:303] MyString: 0x100100f60 RetainCount:1<br> StringPointerTest[2253:303] PrintPointer:0x100100f60 RetainCount:2<br> StringPointerTest[2253:303] PrintPointer:0x100100f60 RetainCount:1152921504606846975<br> StringPointerTest[2253:303] PrintPointer:0x100100f60 RetainCount:1152921504606846975<br></p> </blockquote> <p>If I modify main and remove the pool<br></p> <pre><code>int main(int argc, const char * argv[]) { TestStringPointer *test = [[TestStringPointer alloc] init]; NSString *myString = [NSString stringWithUTF8String:"Hello World"]; NSLog(@"MyString: %p \n RetainCount:%lu", myString, [myString retainCount]); [test setStringTest:myString]; [test printPointer]; [myString release]; while (1) { [test printPointer]; } return 0; } </code></pre> <p>All is right... Forever...</p> <blockquote> <p>StringPointerTest[423:303] MyString: 0x10010a670 RetainCount:1 <br> StringPointerTest[423:303] PrintPointer:0x10010a670 RetainCount:2 <br> StringPointerTest[423:303] PrintPointer:0x10010a670 RetainCount:1 <br> ...</p> </blockquote>

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