Re: Do you have to delete a function pointer ?
<wongjoekmeu@yahoo.com> wrote in message
news:1151138582.839954.269750@u72g2000cwu.googlegroups.com...
Hiya all,
I am trying to use function pointers. I know that usually if you use a
pointer to an object, you have to release the memory at the end by
calling the delete keyword. I was wondering if this is the same for
function pointers.
No. If you use a pointer to an object, you don't always needed to delete
it, only if you used new on it. Maybe an example would help:
int a;
int* intp = a;
intp is an integer pointer that you should not delete, because it is simply
pointing to another object (in this case the interger a). Since you didn't
use new, you don't use delete. Same with function pointers. You don't use
new to declare the memory of the function, you just make the pointer point
to it, so you don't have to delete it.
And if yes, how do you do that ?
You don't.
And how do you assign it to 0 or Null.
Same as any pointer.
MyFuncPointer = NULL;
Here below I have written a small program. I
use an array of function pointer. Because the function pointer is
located in the main() function, I know that when the program exits,
memory is automatically released. But I what if I use it in another
function which I call many times where the function pointer is being
assigned many times. How then should I released the memory ? Many
thanks in advance.
Like said above, you don't have to. The memory for the functions will be
handled by the OS when it cleans up the class (functions actually exist in
the executable files and just get copied to memory, they aren't actually
released individually, they just go away when the program memory gets
released).
robert
#include <iostream>
#include <map>
#include <string>
using namespace std;
class test
{
public:
void f()
{
cout<<"f function"<<endl;
}
void g()
{
cout<<"g function"<<endl;
}
};
int main()
{
void (test::*fArr[2])();
test t ;
map<string, int> fP ;
fP["f"] = 0;
fP["g"] = 1;
fArr[0] = &test::f;
fArr[1] = &test::g;
(t.*fArr[fP["f"]])();
cout<<"Program finish"<<endl;
return 0;
}