void *

Hi,


Could someone please tell me , that if I've a function that takes a void* as an argument, then, is there any way to know, exactly which type of pointer has been passed by the calling function.

e.g.

Code:

---

  int main()
  {
      int i=5;
      func(&i);

      char c='c';
      func(&c);
  }
 

  void func(void* p)
  {
 
    // How can I know here, whether to cast p as int*, or char* to read the correct values ??

  }

---

[code tags added by ygfperson]

Quote:

---

Originally posted by palette
Hi,


Could someone please tell me , that if I've a function that takes a void* as an argument, then, is there any way to know, exactly which type of pointer has been passed by the calling function.

e.g.

int main()
{
int i=5;
func(&i);

char c='c';
func(&c);
}


void func(void* p)
{

// How can I know here, whether to cast p as int*, or char* to read the correct values ??

}

---

You can't, well not that I know of. Why don't you make 2 functions OR use templates. Look them up on google or here if you need further explanation.

Quote:

---

Originally posted by palette
Hi,


Could someone please tell me , that if I've a function that takes a void* as an argument, then, is there any way to know, exactly which type of pointer has been passed by the calling function.

---

Not easilly......that's the problem with void pointers.....they strip away type info...

There are better ways than ussing void params...

1. Use a pointer to a base class , inherit the data you want to pass from this base class, and pass a pointer to this bas class to the function....if you have used virtual functions properly, it should work

2. Overload the function for each type you wish to pass.