How to make derived virtual member function in a _beginthread work?

[Jonathan]

I am trying to figure out a way to call the derived virtual member function
(test) for the _beginthread, which takes void(*pmf)(void*). Listed below
are the base/derived class defs. Read solution #2 (Danny Kalev - 10min0800.asp)
but could't figure out for this scenario. Any suggestion?

#include <iostream.h>
#include <windows.h>
class BaseClass
{
public:
BaseClass(void) {};
virtual ~BaseClass(){};
virtual void test(void) = 0;
private:
};

class DerivedClassA : virtual public BaseClass
{
public:
DerivedClassA(void){};
virtual ~DerivedClassA() {};
virtual void test(void) {};
protected:
private:
};

void main(void)
{
BaseClass *cTab;
cTab = new DerivedClassA();
cTab->test();
return;
}


Regards,
Jonathan

[Johnny]

Hi!

you wrote:
BaseClass *cTab;
cTab = new DerivedClassA();
cTab->test();

try this one:

DerivedClassA *cTab;
cTab = new DerivedClassA();
cTab->test();

How would the compiler know which one of your virtual member functions to
call?

"Jonathan" <jjb@nasa2.ksc.nasa.gov> wrote:
>
>I am trying to figure out a way to call the derived virtual member function
>(test) for the _beginthread, which takes void(*pmf)(void*). Listed below
>are the base/derived class defs. Read solution #2 (Danny Kalev - 10min0800.asp)
>but could't figure out for this scenario. Any suggestion?
>
>#include <iostream.h>
>#include <windows.h>
> class BaseClass
> {
> public:
> BaseClass(void) {};
> virtual ~BaseClass(){};
> virtual void test(void) = 0;
> private:
> };
>
> class DerivedClassA : virtual public BaseClass
> {
> public:
> DerivedClassA(void){};
> virtual ~DerivedClassA() {};
> virtual void test(void) {};
> protected:
> private:
> };
>
> void main(void)
> {
> BaseClass *cTab;
> cTab = new DerivedClassA();
> cTab->test();
> return;
> }
>
>
> Regards,
> Jonathan
>

[Jonathan]

Yes, it will call the right class, but I am still trying to figure out how
to call a virtual member function of the derived class in _beginthread call.


Regards,
Jonathan

"Johnny" <p166@freemail.hu> wrote:
>
>Hi!
>
>you wrote:
>BaseClass *cTab;
>cTab = new DerivedClassA();
>cTab->test();
>
>try this one:
>
>DerivedClassA *cTab;
>cTab = new DerivedClassA();
>cTab->test();
>
>How would the compiler know which one of your virtual member functions to
>call?
>
>"Jonathan" <jjb@nasa2.ksc.nasa.gov> wrote:
>>
>>I am trying to figure out a way to call the derived virtual member function
>>(test) for the _beginthread, which takes void(*pmf)(void*). Listed below
>>are the base/derived class defs. Read solution #2 (Danny Kalev - 10min0800.asp)
>>but could't figure out for this scenario. Any suggestion?
>>
>>#include <iostream.h>
>>#include <windows.h>
>> class BaseClass
>> {
>> public:
>> BaseClass(void) {};
>> virtual ~BaseClass(){};
>> virtual void test(void) = 0;
>> private:
>> };
>>
>> class DerivedClassA : virtual public BaseClass
>> {
>> public:
>> DerivedClassA(void){};
>> virtual ~DerivedClassA() {};
>> virtual void test(void) {};
>> protected:
>> private:
>> };
>>
>> void main(void)
>> {
>> BaseClass *cTab;
>> cTab = new DerivedClassA();
>> cTab->test();
>> return;
>> }
>>
>>
>> Regards,
>> Jonathan
>>
>

[Johnny]

Read the _beginthread, beginthreadex function documentation in Visual C++
Documentation section in MSDN.

"Jonathan" <jjb@nasa2.ksc.nasa.gov> wrote:
>
>Yes, it will call the right class, but I am still trying to figure out how
>to call a virtual member function of the derived class in _beginthread call.
>
>
>Regards,
>Jonathan
>
>"Johnny" <p166@freemail.hu> wrote:
>>
>>Hi!
>>
>>you wrote:
>>BaseClass *cTab;
>>cTab = new DerivedClassA();
>>cTab->test();
>>
>>try this one:
>>
>>DerivedClassA *cTab;
>>cTab = new DerivedClassA();
>>cTab->test();
>>
>>How would the compiler know which one of your virtual member functions
to
>>call?
>>
>>"Jonathan" <jjb@nasa2.ksc.nasa.gov> wrote:
>>>
>>>I am trying to figure out a way to call the derived virtual member function
>>>(test) for the _beginthread, which takes void(*pmf)(void*). Listed below
>>>are the base/derived class defs. Read solution #2 (Danny Kalev - 10min0800.asp)
>>>but could't figure out for this scenario. Any suggestion?
>>>
>>>#include <iostream.h>
>>>#include <windows.h>
>>> class BaseClass
>>> {
>>> public:
>>> BaseClass(void) {};
>>> virtual ~BaseClass(){};
>>> virtual void test(void) = 0;
>>> private:
>>> };
>>>
>>> class DerivedClassA : virtual public BaseClass
>>> {
>>> public:
>>> DerivedClassA(void){};
>>> virtual ~DerivedClassA() {};
>>> virtual void test(void) {};
>>> protected:
>>> private:
>>> };
>>>
>>> void main(void)
>>> {
>>> BaseClass *cTab;
>>> cTab = new DerivedClassA();
>>> cTab->test();
>>> return;
>>> }
>>>
>>>
>>> Regards,
>>> Jonathan
>>>
>>
>

[Jonathan]

Johnny,
Thanks for your response. But what I am really trying to make the derived
virtual member function call within the _beginthread call. As I stated initally
I read and tried a solution #2(non-static call method) of Danny Kalev for
this case and found that it will not work for the virtual member function.
Yes, I read the Visual C++ doc. and know how to call it. Thanks again but
can someone else give a try.

Regards,
Jonathan

"Johnny" <p166@freemail.hu> wrote:
>
>Read the _beginthread, beginthreadex function documentation in Visual C++
>Documentation section in MSDN.
>
>"Jonathan" <jjb@nasa2.ksc.nasa.gov> wrote:
>>
>>Yes, it will call the right class, but I am still trying to figure out
how
>>to call a virtual member function of the derived class in _beginthread
call.
>>
>>
>>Regards,
>>Jonathan
>>
>>"Johnny" <p166@freemail.hu> wrote:
>>>
>>>Hi!
>>>
>>>you wrote:
>>>BaseClass *cTab;
>>>cTab = new DerivedClassA();
>>>cTab->test();
>>>
>>>try this one:
>>>
>>>DerivedClassA *cTab;
>>>cTab = new DerivedClassA();
>>>cTab->test();
>>>
>>>How would the compiler know which one of your virtual member functions
>to
>>>call?
>>>
>>>"Jonathan" <jjb@nasa2.ksc.nasa.gov> wrote:
>>>>
>>>>I am trying to figure out a way to call the derived virtual member function
>>>>(test) for the _beginthread, which takes void(*pmf)(void*). Listed below
>>>>are the base/derived class defs. Read solution #2 (Danny Kalev - 10min0800.asp)
>>>>but could't figure out for this scenario. Any suggestion?
>>>>
>>>>#include <iostream.h>
>>>>#include <windows.h>
>>>> class BaseClass
>>>> {
>>>> public:
>>>> BaseClass(void) {};
>>>> virtual ~BaseClass(){};
>>>> virtual void test(void) = 0;
>>>> private:
>>>> };
>>>>
>>>> class DerivedClassA : virtual public BaseClass
>>>> {
>>>> public:
>>>> DerivedClassA(void){};
>>>> virtual ~DerivedClassA() {};
>>>> virtual void test(void) {};
>>>> protected:
>>>> private:
>>>> };
>>>>
>>>> void main(void)
>>>> {
>>>> BaseClass *cTab;
>>>> cTab = new DerivedClassA();
>>>> cTab->test();
>>>> return;
>>>> }
>>>>
>>>>
>>>> Regards,
>>>> Jonathan
>>>>
>>>
>>
>

[James Curran]

void ThreadFunc(void* ptr)
{
Base* pB = reinterpret_cast<Base*>(ptr);
pB->test();
}


main()
{
Derived* pD = new Derived;
_beginThread(ThreadFunc, 0 , pD);
}

--
Truth,
James Curran
www.NJTheater.com (Professional)
www.NovelTheory.com (Personal)
www.BrandsForLess.Com (Day Job)


"Jonathan" <jjb@nasa2.ksc.nasa.gov> wrote in message
news:3bb8d148$1@news.devx.com...
>
> I am trying to figure out a way to call the derived virtual member
function
> (test) for the _beginthread, which takes void(*pmf)(void*). Listed below
> are the base/derived class defs. Read solution #2 (Danny Kalev -
10min0800.asp)
> but could't figure out for this scenario. Any suggestion?
>
> #include <iostream.h>
> #include <windows.h>
> class BaseClass
> {
> public:
> BaseClass(void) {};
> virtual ~BaseClass(){};
> virtual void test(void) = 0;
> private:
> };
>
> class DerivedClassA : virtual public BaseClass
> {
> public:
> DerivedClassA(void){};
> virtual ~DerivedClassA() {};
> virtual void test(void) {};
> protected:
> private:
> };
>
> void main(void)
> {
> BaseClass *cTab;
> cTab = new DerivedClassA();
> cTab->test();
> return;
> }
>
>
> Regards,
> Jonathan
>