目標C線程

Question

我有其中其-main方法內我使用[NSThread detachNewThreadSelector:@selector(aMethod:) toTarget:self withObject:anArgument];

aObject（我的NSOperation子類的實例變量）是一種弱引用一個autoreleased陣列的對象的的NSOperation該方法 - 主內返回...

-(void)main { 

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 

    NSArray *clients = [group produceClients]; // clients array is an autorelease instance 
    self->aObject = [clients objectAtIndex:3]; // a weak reference, Lets say at index three! 

    [NSThread detachNewThreadSelector:@selector(aMethod:) 
          toTarget:self 
          withObject:@"I use this for another thing"]; 

    // Do other things here that may take some time 

    [pool release]; 
} 

-(void)aMethod:(NSString*)aStr { 

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 

    // aStr object is reserved for another functionality 
    // I know that I could pass a NSDictionary with a number of entries, which would be 
    // retained by `detachNewThreadSelector` but then ... 
    // I wouldn't have to ask this question ! :) 

    // Do several things with aObject, which is a weak reference as described above. 
    NSLog(@"%@", [self->aObject.id]); 
    // Is it safe ? 

    [pool release]; 
} 

我知道NSThread的detachNewThreadSelector方法保留self和withObject：anArgument，但會發生什麼變化？aObject在執行分離線程（aMethod :)期間是否確實會存在？ Self由detachNewThreadSelector保留，這是否意味着-main線程池將被延遲釋放，因爲它被保留，因此clients將存在，因此aObject將存在？
或者-main（NSOperation）線程會在-aMethod（NSThread）完成之前完成執行並釋放，因此在那裏使用aObject是不安全的？

真正的問題是：當調用從一個線程中[NSThread detachNewThreadSelector:@selector(aMethod:) ...toTarget:self ...]，不會被保留的方式，它的自動釋放的情況下（clients陣列）是安全的aMethod（self->aObject）所使用的最後一個線程（可以通過弱引用說）？

Answer 1

你的方法似乎非常不穩定，但我不是多線程專家，所以我可能是錯的。您的客戶端陣列位於主要的自動釋放池中，您無法放心將等待您的aMethod線程完成以消除。這是怎麼回事：

-(void)main { 

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 

    [NSThread detachNewThreadSelector:@selector(aMethod:) 
          toTarget:self 
          withObject:@"I use this for another thing"]; 

    [pool release]; 
} 

-(void)aMethod:(NSString*)aStr { 

    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 

    NSArray *clients = [group produceClients]; // clients array is an autorelease instance 
    self->aObject = [clients objectAtIndex:3]; // a weak reference, Lets say at index three! 

    [pool release]; 
} 

用這種方法，你的客戶端陣列是在線程的autorelease池。