C++.错误:void 不是指向对象的类型 [英] C++. Error: void is not a pointer-to-object type

问题描述

我有一个 C++ 程序:

I have a C++ program:

struct arguments
{
  int a, b, c;  
  arguments(): a(3), b(6), c(9) {}
};

class test_class{
  public:

    void *member_func(void *args){
      arguments vars = (arguments *) (*args); //error: void is not a 
                                              //pointer-to-object type

      std::cout << "
" << vars.a << "	" << vars.b << "	" << vars.c << "
";
    }
};

编译时报错:

error: ‘void*’ is not a pointer-to-object type

有人可以解释我做错了什么导致这个错误吗?

Can someone explain what I am doing wrong to produce this error?

推荐答案

您在将 void * 转换为具体类型之前取消引用它.你需要反过来做:

You are dereferencing the void * before casting it to a concrete type. You need to do it the other way around:

arguments vars = *(arguments *) (args);

这个顺序很重要，因为编译器不知道如何将 * 应用到 args(这是一个 void * 并且可以' 不会被取消引用).您的 (arguments *) 告诉它该做什么，但为时已晚，因为取消引用已经发生.

This order is important, because the compiler doesn't know how to apply * to args (which is a void * and can't be dereferenced). Your (arguments *) tells it what to do, but it's too late, because the dereference has already occurred.

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