In article <DONDZES.95Mar27152705@rapnet.sanders.lockheed.com>,
dondzes@rapnet.sanders.lockheed.com says...
>
>
>can someone please explain to me why this program will not compile ? I
am
>using g++ 2.4.3. I would _very_ much appreciate an email response.
>
In order to take the address of a member function of a c++ class, that
member function must static.  This was setup by Bjorne Stroustrup.

 or explicitly make it a pointer to member function of THAT
 class.....

 class A {.....};

 int (A::*mfp)();
/* noe 'mfp' can be made to point to a member function of class A, the func
     returns an integer and takes no args
*/

In article <DONDZES.95Mar27152705@rapnet.sanders.lockheed.com>,
dondzes@rapnet.sanders.lockheed.com says...
>
>
>can someone please explain to me why this program will not compile ? I
am
>using g++ 2.4.3. I would _very_ much appreciate an email response.
>
In order to take the address of a member function of a c++ class, that
member function must static.  This was setup by Bjorne Stroustrup.

In article <3lfi9i$ob2@newmedia.comptons.com>,
Brandy bogard <BBogard@comptons.com> wrote:
>In order to take the address of a member function of a c++ class, that
>member function must static.  This was setup by Bjorne Stroustrup.

False.  You can take the address of a member function, provided you
use it in a pointer to member context, and about half a dozen other
rules are followed, especially if you cast it.

Warner

Humberto Hernandez
University of Michigan

>class blob {

>private:
>  char* (*fp)();               // my function pointer

To declare a pointer to a member function of blob do:

char *(blob::*fp)();

>  char* f1() {return "1";};
>  char* f2() {return "2";};
>public:
>  void setup(int x){
>    if (x == 1)
>      fp = &(this->f1);        // compiler error
>    else
>      fp = &(blob::f2);        // compiler error
>  }
>};

I am for the breif answer but I do not know what happened with my
previous and more elaborate response. I hope this helps. Good luck.
Humberto Hernandez
University of Michigan

dondzes@rapnet.sanders.lockheed.com (David A. Ondzes x5-2707) writes:


>can someone please explain to me why this program will not compile ? I am
>using g++ 2.4.3. I would _very_ much appreciate an email response.

>David

Look up "pointer to member" or "member pointer" or some such in your
handy C++ book.  A member function is a whole different kind of beast
from a "normal" function.


>------------------------------------------------------------------------
>#include <stdio.h>
>#include <stdlib.h>
>#include <stream.h>

>class blob {

>private:
>  char* (*fp)();               // my function pointer

change above line to this:

   char* (blob::*fp)();

>  char* f1() {return "1";};
>  char* f2() {return "2";};
>public:
>  void setup(int x){
>    if (x == 1)
>      fp = &(this->f1);        // still wrong
>    else
>      fp = &(blob::f2);        // OK now.
>  }
>};

>int main()
>{
>  blob b;

>  b.setup(1);
>  b.setup(2);
>}


Kevin Kelley

        **    +                 '.          -<>-            o
      ******      O       O      ,'     _              o
      ******                     .    '(_).                      +
        **            O         ',                  kelleyk@ccmail.tt.com

In article <DONDZES.95Mar27152705@rapnet.sanders.lockheed.com>,
David A. Ondzes x5-2707 <dondzes@rapnet.sanders.lockheed.com> wrote:
>#include <stdio.h>
>#include <stdlib.h>
>#include <stream.h>
>
>class blob {
>
>private:
>  char* (*fp)();               // my function pointer

Make this char* (blob::*fp)(); and it compiles fine.

The comp.lang.c++ faq discusses the difference between a pointer to a
C function and to a C++ member function.

--
Name: Arnoud Martens, Utrecht, the Netherlands,  tel: +31-30-732679
E-mail: arnoudm@ijssel.xs4all.nl WWW: http://www.xs4all.nl/~arnoudm

can someone please explain to me why this program will not compile ? I am
using g++ 2.4.3. I would _very_ much appreciate an email response.

David
------------------------------------------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <stream.h>

class blob {

private:
  char* (*fp)();               // my function pointer

  char* f1() {return "1";};
  char* f2() {return "2";};
public:
  void setup(int x){
    if (x == 1)
      fp = &(this->f1);        // compiler error
    else
      fp = &(blob::f2);        // compiler error
  }
};

int main()
{
  blob b;

  b.setup(1);
  b.setup(2);
}