c - 如何声明指向不同数据类型的指针，但它们将占用相同的内存空间

Question

这是我的代码

int main()
{ 
   char *pchar;
   short *pshort;
   int *pint;
   long *plong;
   float *pfloat;
   double *pdouble;

   pchar = pshort = pint = plong = pfloat = pdouble;
   printf("sizeof *pchar   is = %u\n",sizeof(pchar));
   printf("sizeof *pshort  is = %u\n",sizeof(pshort));
   printf("sizeof *pint    is = %u\n",sizeof(pint));
   printf("sizeof *plong   is = %u\n",sizeof(plong));
   printf("sizeof *pfloat  is = %u\n",sizeof(pfloat));
   printf("sizeof *pdouble is = %u\n",sizeof(pdouble));

   return 0;
}

我希望这些指针变量中的每一个都指向不同的数据类型，但它们将在内存中占用相同的空间量。我怎样才能做到这一点？

Answer 1

创建一个通用指针。

When a variable is declared as being a pointer to type void it is known as a generic pointer. Since you cannot have a variable of type void, the pointer will not point to any data and therefore cannot be dereferenced. It is still a pointer though, to use it you just have to cast it to another kind of pointer first. Hence the term Generic pointer.

这个link有一个例子。