在char *指针上的reinterpret_cast

Question

I had to change the prototype of a function getData() which is basically a legacy source code. Upon changing it from returning a char* as shown below, I started getting compile errors due to static_cast .The question I have is , Is it safe to use reinterpret_cast , instead of static_cast ?

  class C1{

     public:

     //void *getData() {return data;} //Legacy implementation*
     char *getData() {return data;}  //My new implementation

     private:
       char data[100];
   };

   int main()
   {
       C1 myobj;   
       unsigned char* begin;

       begin=static_cast<unsigned char*>(myobj.getData());  *//<== This gives compile error.use reinterpret_cast ?*
       return 0;
   }

Is there a better solution than reinterpret_cast ?

Answer 1

You can static_cast from a void * to any pointer type, or between pointers to related types in the sense when one herites from the other.

reinterpret_cast is intended to be used between pointers to unrelated types. Is is equivalent to a static_cast from first type to void * followed with a static_cast from void * to second type. It T and U are unrelated types:

U *u = ...;
T *t;

t = reinterpret_cast<T *>(u);  /* strictly the same as would be
t = static_cast<T *>(static_cast<void *>(u));  */

Answer 2

It depends of what you want to accomplish. If you want to just use the bitwise representation of data , with each element interpreted as unsigned char , then reinterpret_cast is the way to go.

Your question doesn't give us enough details to figure out if it is "safe" in your case.