首先，让我们把定义更正一下。内存泄漏是指动态分配内存，例如使用malloc()，并且所有对内存的引用都在没有相应的free的情况下丢失。制作一个简单的方法是这样的:

#define BLK ((size_t)1024)
while(1){
    void * vp = malloc(BLK);
}

注意，每次在while(1)循环中，分配1024(+开销)字节，并将新地址分配给vp;没有指向之前malloc 'Ed块的剩余指针。这个程序保证运行到堆用完为止，并且没有办法恢复任何malloc'ed内存。内存从堆中“泄漏”出来，再也看不见了。

你所描述的，听起来就像

int main(){
    void * vp = malloc(LOTS);
    // Go do something useful
    return 0;
}

你分配内存，使用它直到程序结束。这不是内存泄漏;它不会损害程序，并且当程序终止时，所有的内存将被自动清除。

一般来说，应该避免内存泄漏。首先，因为就像你头顶上的高度和飞机库里的燃料一样，已经泄漏且无法恢复的内存是无用的;其次，在一开始就正确编码，不泄漏内存，比后来发现内存泄漏要容易得多。

我想你已经回答了自己的问题。最大的缺点是它们如何干扰内存泄漏检测工具，但我认为这个缺点对于某些类型的应用程序来说是一个巨大的缺点。

我使用的遗留服务器应用程序应该是坚如磐石的，但它们有泄漏，并且全局变量确实妨碍了内存检测工具。这是件大事。

在杰瑞德·戴蒙德(Jared Diamond)的《崩塌》(Collapse)一书中，作者想知道那个人在想什么，他砍倒了复活节岛上的最后一棵树，而这棵树是他建造独木舟离开该岛所需要的。我想知道许多年前第一个全局变量被添加到我们的代码库的那一天。那是它应该被抓住的日子。

如果它是故意的，它真的不是一个泄漏，它不是一个问题，除非它是一个相当大的内存，或者可以增长到一个相当大的内存。在程序的生命周期内不清理全局分配是很常见的。如果泄漏是在服务器或长时间运行的应用程序中，随着时间的推移而增长，那么这就是一个问题。

Some great answers here. To add another perspective to this question, I'll address a case where memory leak is not only acceptable but desirable: in Windows drivers environment the developer provides a set of callbacks that are being run by the OS whenever required. One of the callbacks is a 'Shutdown' callback, which runs prior to system being shut off/restarted. Unlike standard situations, not only memory release is not necessary (system will be off in a moment), it's even discouraged - to make the shutdown as fast as possible and prevent the overhead of memory management.

看来你对“内存泄漏”的定义是“我自己不清理的内存”。所有现代操作系统都会在程序退出时释放它。然而，由于这是一个c++问题，您可以简单地将所讨论的内存包装在适当的std::auto_ptr中，当它超出作用域时将调用delete。

I'm going to give the unpopular but practical answer that it's always wrong to free memory unless doing so will reduce the memory usage of your program. For instance a program that makes a single allocation or series of allocations to load the dataset it will use for its entire lifetime has no need to free anything. In the more common case of a large program with very dynamic memory requirements (think of a web browser), you should obviously free memory you're no longer using as soon as you can (for instance closing a tab/document/etc.), but there's no reason to free anything when the user selects clicks "exit", and doing so is actually harmful to the user experience.

为什么?释放内存需要接触内存。即使您的系统的malloc实现碰巧没有在分配的内存块附近存储元数据，您也可能会遍历递归结构，只是为了找到所有需要释放的指针。

Now, suppose your program has worked with a large volume of data, but hasn't touched most of it for a while (again, web browser is a great example). If the user is running a lot of apps, a good portion of that data has likely been swapped to disk. If you just exit(0) or return from main, it exits instantly. Great user experience. If you go to the trouble of trying to free everything, you may spend 5 seconds or more swapping all the data back in, only to throw it away immediately after that. Waste of user's time. Waste of laptop's battery life. Waste of wear on the hard disk.

这不仅仅是理论上的。每当我发现自己加载了太多的应用程序，磁盘开始抖动时，我甚至不会考虑点击“退出”。我以最快的速度到达一个终端，输入killall -9…因为我知道"退出"只会让情况更糟。