转换为 void* 并返回 Original_Data_Type* [英] Casting to void* and Back to Original_Data_Type*

问题描述

我多次看到并使用了C++，特别是在各种线程实现中.我想知道这样做是否有任何陷阱/问题?当我们强制转换为 void* 并再次返回时，有什么方法可能会遇到错误或未定义的条件吗?如果有这些问题，我们应该如何解决?

I have seen and used this many times is C++, specially in various thread implementations. What I wonder is if there are any pitfalls/ issues of doing this? Is there any way that we could run in to an error or undefined condition when we are casting to void* and back again? How should we resolve such issues if there are any?

谢谢.

推荐答案

我想知道这样做是否有任何陷阱/问题?

在将 void* 转换回特定类型时，您需要绝对确定，否则，您最终会遇到 未定义行为 和潜在的灾难.一旦你使用void *，你就会失去类型安全.很难跟踪void *的类型实际上是指向，无法保证或确定它确实指向您要将其类型转换回的类型.

You need to be absolutely sure while casting the the void* back to the particular type, if you don't, you end up with an Undefined behavior and a potential disaster. Once you use void * you lose type safety.It is difficult to keep track of what type a void * is actually pointing to, there is no way to guarantee or determine that it indeed points to the type to which you are going to typecast it back to.

当我们转换为 void* 并再次返回时，有没有什么方法可能会遇到错误或未定义的情况?

是的，#1中提到的场景.

如果有这些问题，我们应该如何解决?

在 C++ 中完全避免使用 void *，而是使用模板和继承.
在 C 中，您可能在某些情况下绝对需要它，但尽量减少它的使用.
底线，
C/C++ 允许你用脚射击自己，这取决于你做或不做.

Avoid using void * in C++ completely, instead use templates and inheritance.
In C you might absoultely need it in certain situations but try to keep its use to a minimum.
Bottomline,
C/C++ allows you to shoot yourself in foot, it is up to you to do or not do so.

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