c# - 将指针(即 int[])传递给 DLL 时， "fixed"真的能保证任何事情吗？

Question

我尝试搜索这个但没有找到任何东西，但是当将 int[] 作为指针传递到 native DLL 函数时，是否仍然存在 DLL 可以维护对指针的引用的危险，并且然后在“固定” block 终止后尝试再次访问它？如果 GC 移动了您的数组，这不会导致内存访问错误吗？如果是这样，你如何解决这个问题？或者这是不太可能发生的情况？

Answer 1

更新:这个问题是 my blog on December 11th 2012 的主题.感谢您提出很好的问题!

---

tried searching for this but haven't found anything

当您对语言有疑问时，请考虑阅读语言规范。

when passing an int[] into a native DLL function as a pointer, isn't there still the danger that the DLL could maintain a reference to the pointer, and then try to access it again after the "fixed" block has terminated?

是的。正如语言规范所述:

---

It is the programmer’s responsibility to ensure that pointers created by fixed statements do not survive beyond execution of those statements. For example, when pointers created by fixed statements are passed to external APIs, it is the programmer’s responsibility to ensure that the APIs retain no memory of these pointers.

---

Wouldn't this cause memory access errors if the GC has moved your array?

是的!

If so, how do you get around this?

你不需要。正如语言规范所述，你永远不能这样做。因为你永远不会那样做，所以你不必想办法绕过它。这就像问“我如何从致命的枪击事件中恢复过来？”你不会——如果你不想以死告终，那么一个好的规则是“首先不要朝自己开枪”。

Or is this an unlikely scenario?

您是否可能编写调用违反托管代码规则的 DLL 的 C# 程序？ 我不知道!你告诉我——这是你认为你可能会被诱惑去做的事情吗？