关于ios内存管理的问题
sdk是ios6.1，不开ARC。

#import <sys/sysctl.h>
#import <mach/mach.h>

-(id)init
{
    self=[super init];
    [self usedMemory];
    [self addtitle:@"d"];
     [self usedMemory];
    return self;
}

-(void)addtitle:(NSString *)title
{
    for (double i=0; i<200000;i++) {
        
       // NSString *T2=[@" >    " stringByAppendingString:title];
        
        NSObject * T2=[[NSObject alloc]init];
        [T2 release];
    }
}

- (void )usedMemory
{
    task_basic_info_data_t taskInfo;
    mach_msg_type_number_t infoCount = TASK_BASIC_INFO_COUNT;
    kern_return_t kernReturn = task_info(mach_task_self(),
                                         TASK_BASIC_INFO,
                                         (task_info_t)&taskInfo,
                                         &infoCount);
    
    if (kernReturn != KERN_SUCCESS
        ) {
        NSLog(@"Nofound");
    }
    
    NSLog(@"Memery%f", taskInfo.resident_size / 1024.0 / 1024.0);;
}

运行结果：
2013-09-14 18:56:24.240 menerytest[5913:c07] Memery16.789062
2013-09-14 18:56:24.281 menerytest[5913:c07] Memery17.128906

如果把 [T2 release]; 注释掉:
2013-09-14 19:05:41.786 menerytest[6476:c07] Memery16.890625
2013-09-14 19:05:41.804 menerytest[6476:c07] Memery20.320312

原本T2用得是 NSString *T2=[@" > " stringByAppendingString:title];
不release内存有可观的增长，release后的内存增长类似上面第一个结果，但是程序最后会crash掉。
为啥release掉还是有内存泄漏了呢？尽管十分微小。而且为什么“[@" > " stringByAppendingString:title]” release后会crash呢？

[解决办法]
stringByAppendingString:title 返回的NSString已经是autorelease的了，你无需再手动去release
[解决办法]
你过度释放掉了