When I use The Class of NSMutableArray , first I alloc a NSMutableArray,Then Add Five Object to the NSMutableArray, last Remove All Object from the Array .the Memory Used can't Release.

Question

Level 1

0 points

The Follow is My Code for the Question:

NSMutableArray * _test = [[NSMutableArray alloc] init] ;

NSString * str = [[NSString alloc]initWithFormat:@"Test12312313"];

NSLog(@"retainCount0:%d",[str retainCount]);

[_test addObject:str];

[str release];

NSLog(@"retainCount0:%d",[str retainCount]);

double duse = [self usedMemory];

NSLog(@"Test0:%.10f",duse);

int n = 0;

{

while (n < 10000 ) {

n++;

NSString * str = [[NSString alloc]initWithFormat:@"Test12312313"];

[_test addObject:str];

str = nil;

duse = [self usedMemory];

NSLog(@"Test1:%.10f",duse);

}

[_test removeAllObjects];

_test = nil;

str = nil;

duse = [self usedMemory];

NSLog(@"Test2:%.10f",duse);

}

duse = [self usedMemory];

NSLog(@"Test3:%.10f",duse);

Posted on Oct 15, 2013 5:56 PM

Reply

Answer 1

In general, retainCount is widely considered useless. Best to simply ignore that method.

I'd also encourage using automatic reference counting (ARC) here, and not manual retain-release. Here's some related llvm documentation with ARC details and here's a quick overview. Some example code here.

If you want to check for leaks in your code, it's also generally best to use Instruments.

Reply