泄漏工具不会报告OS X上的内存泄漏 [英] leaks tool doesn't report memory leak on os x

问题描述

我正在尝试从命令行学习如何使用泄漏工具，这是我的代码，应在NSString上产生泄漏:

I am trying to learn how to use leaks tool from the command line, here is my code that should produce a leak on NSString:

#import <Foundation/Foundation.h>
#import <unistd.h>

int main(int argc, const char *argv[])
{
    NSString *string = [[NSString alloc] init];

    pid_t pid = getpid();
    NSLog(@"pid: %d", pid);

    string = nil;
    [NSThread sleepForTimeInterval:20];

    return 0;
}

我了解到泄漏会每10秒刷新一次(不确定这是否成立，但是我将间隔设置为20秒).

I learned that leaks refreshes itself every 10 seconds (not sure if this is true, but I set the interval to 20 seconds).

这应该会产生泄漏，因为它不在自动发布池中，并且我还使用-fno-objc-arc进行了编译以确保安全".

This should produce leaks because it is not in auto release pool and also I compiled with -fno-objc-arc for "safety".

我尝试多次运行泄漏[pid]，但没有泄漏报告.我在这里做错了什么? 另外，我是命令行迷，我真的很想能够使用类似于valgrind的东西，它不非常支持os x 10.8.烦人的是，为了使用泄漏工具，我不得不在代码中入睡.

I tried to run leaks [pid] multiple times with no leaks reported. What am I doing wrong here? Also, I am a command line fan and really want to be able to use something similar to valgrind, which doesn't support os x 10.8 very well. It is annoying that I have to put sleep in my code in order to use leaks tool.

任何人都可以在这里点亮一些灯光吗?

Can anyone please shine some lights here?

推荐答案

NSString *string = [[NSString alloc] init];

返回一个空字符串的共享实例(并且多次调用返回相同的实例). Foundation框架保留对此共享实例的引用，因此 没有内存泄漏.

returns a shared instance of an empty string (and multiple calls return the same instance). The Foundation framework keeps a reference to this shared instance, therefore there is no memory leak.

在其他不可变类(NSArray，NSDictionary)上也可以观察到相同的行为.

The same behaviour can be observed with other immutable classes (NSArray, NSDictionary).

如果您将行替换为

NSMutableString *string = [[NSMutableString alloc] init];

然后您将看到内存泄漏.

then you will see a memory leak.

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