dev-cpp-users

[Dev-C++] Pointer to function

[Harry P. <wi...@ma...>]

Hello, All!!!

I need to call function-member of class by its pointer. For example:


//- main.h ----------------------------------
#include <iostream>
#include <stdlib.h>

class A
{
    public:
        int f (void) { return 5; }
};

//- main.cpp --------------------------------
#include "main.h"

using namespace std;

int main(int argc, char *argv[])
{
        A cA;

        int ( A::*pFunc ) (void);
    
        pFunc = &A::f;
        
//        cout << ??? How I can call cA.f() using the pointer pFunc?

        system("PAUSE");        
        return 0;
}

Re: [Dev-C++] Pointer to function

[David M. <dml...@co...>]

int result3 = (instance.*pt2Member)(12, 'a', 'b');    // Outside class
int result4 = (*this.*pt2Member)(12, 'a', 'b');       // Inside class

in your case it would be:
cout << (cA.*pFunc)();

A good tutorial on this topic is avalible @ www.function-pointer.org

Hope this Helps
David McKen

Harry Piterson wrote:
> Hello, All!!!
> 
> I need to call function-member of class by its pointer. For example:
> 
> 
> //- main.h ----------------------------------
> #include <iostream>
> #include <stdlib.h>
> 
> class A
> {
>     public:
>         int f (void) { return 5; }
> };
> 
> //- main.cpp --------------------------------
> #include "main.h"
> 
> using namespace std;
> 
> int main(int argc, char *argv[])
> {
>         A cA;
> 
>         int ( A::*pFunc ) (void);
>     
>         pFunc = &A::f;
>         
> //        cout << ??? How I can call cA.f() using the pointer pFunc?
> 
>         system("PAUSE");        
>         return 0;
> }
> 
> 
> 
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Re[2]: [Dev-C++] Pointer to function

[Harry P. <wi...@ma...>]

Hello David,

Sunday, July 4, 2004, 7:22:29 AM, you wrote:

DM> int result3 = (instance.*pt2Member)(12, 'a', 'b');    // Outside class
DM> int result4 = (*this.*pt2Member)(12, 'a', 'b');       // Inside class

Thank you for the documentation!!! It's all that I really need.

-- 
Best regards,
 Harry                            mailto:wi...@ma...

Re: [Dev-C++] Pointer to function

[Alvin T. <al...@th...>]

if you're using c++ you may want to use virtual functions/polymorphism 
instead of using function pointers...

-alvin


Harry Piterson wrote:
> Hello, All!!!
> 
> I need to call function-member of class by its pointer. For example:
> 
> 
> //- main.h ----------------------------------
> #include <iostream>
> #include <stdlib.h>
> 
> class A
> {
>     public:
>         int f (void) { return 5; }
> };
> 
> //- main.cpp --------------------------------
> #include "main.h"
> 
> using namespace std;
> 
> int main(int argc, char *argv[])
> {
>         A cA;
> 
>         int ( A::*pFunc ) (void);
>     
>         pFunc = &A::f;
>         
> //        cout << ??? How I can call cA.f() using the pointer pFunc?
> 
>         system("PAUSE");        
>         return 0;
> }
> 
> 
> 
> -------------------------------------------------------
> This SF.Net email sponsored by Black Hat Briefings & Training.
> Attend Black Hat Briefings & Training, Las Vegas July 24-29 - 
> digital self defense, top technical experts, no vendor pitches, 
> unmatched networking opportunities. Visit www.blackhat.com
> _______________________________________________
> Dev-cpp-users mailing list
> Dev...@li...
> TO UNSUBSCRIBE: http://www23.brinkster.com/noicys/devcpp/ub.htm
> https://lists.sourceforge.net/lists/listinfo/dev-cpp-users

-- 
Alvin Thompson

Navy: 34
Army: 6

Re[2]: [Dev-C++] Pointer to function

[Harry P. <wi...@ma...>]

Hello Alvin,

It's really slow... My application is critical to run time. I use
thread to handle events and change programm's state.

Tuesday, July 6, 2004, 7:23:47 PM, you wrote:

AT> if you're using c++ you may want to use virtual functions/polymorphism
AT> instead of using function pointers...

AT> -alvin

-- 
Best regards,
 Harry                            mailto:wi...@ma...

Re[2]: [Dev-C++] Pointer to function

[Per W. <pw...@ia...>]

Since the speed difference of a function pointer compared to a virtual
method call is less than a nanosecond on a modern computer - in some cases
the speed difference is zero because of specific c++ code optimizations in
the compiler - you have a major problem if you think virtual method calls
aren't fast enough...

/Per W

On Thu, 8 Jul 2004, Harry Piterson wrote:

> Hello Alvin,
>
> It's really slow... My application is critical to run time. I use
> thread to handle events and change programm's state.
>
> Tuesday, July 6, 2004, 7:23:47 PM, you wrote:
>
> AT> if you're using c++ you may want to use virtual functions/polymorphism
> AT> instead of using function pointers...
>
> AT> -alvin
>
> --
> Best regards,
>  Harry                            mailto:wi...@ma...
>
>
>
> -------------------------------------------------------
> This SF.Net email sponsored by Black Hat Briefings & Training.
> Attend Black Hat Briefings & Training, Las Vegas July 24-29 -
> digital self defense, top technical experts, no vendor pitches,
> unmatched networking opportunities. Visit www.blackhat.com
> _______________________________________________
> Dev-cpp-users mailing list
> Dev...@li...
> TO UNSUBSCRIBE: http://www23.brinkster.com/noicys/devcpp/ub.htm
> https://lists.sourceforge.net/lists/listinfo/dev-cpp-users
>