template class with template members

[Tiny Dolls]

I have a class like this

template<class X>
class A
{
  X m_x;
public:
    X* foo();
    X* bar();
    //others are not related to X
}; 

I would like to get rid of

template<class X> 

for class level but still use it for members. Like this

class A
{
  X m_x;
public:
    template<class X>
    X* foo();
    template<class X>
    X* bar();
    //others are not related to X
}; 

However, I am still stuck at

X m_x; 

[laserlight]

You cannot do that since m_x is a member variable, so its type must be available at that point.

[BenchMark]

You can use void* to get rid of the outer template

class A
{
  void* m_x;
public:
    void* foo();
    void* bar();
    //others are not related to X
};

[2kaud]

Yuk!!

[OReubens]

if you make X a member of A then the X class needs to be fully defined by the time the compiler tries to compile the A class.

if you make a pointer to X or a reference to X member, then you only need a forward reference to X, and the actual definition of X can come later.

you don't need a template function to return an X*, a forward is enough. You will probably need the full X definition when implementing said function though.

[D_Drmmr]

You can use void* to get rid of the outer template

class A
{
  void* m_x;
public:
    void* foo();
    void* bar();
    //others are not related to X
};

That's not really a solution. How will this code be able to create/copy/destroy an instance of X?

@Tiny Dolls
Why do you want to get rid of the class template? What do you want to accomplish at a higher level?
If I had to guess, I'd guess you want to implement some kind of type erasure.
...but I don't like guessing, so I won't elaborate unless I know it's worth the effort.

[Tiny Dolls]

That's not really a solution. How will this code be able to create/copy/destroy an instance of X?

@Tiny Dolls
Why do you want to get rid of the class template? What do you want to accomplish at a higher level?
If I had to guess, I'd guess you want to implement some kind of type erasure.
...but I don't like guessing, so I won't elaborate unless I know it's worth the effort.

Yes I think this is what I am looking for.
I also tried what Benchmark suggested and it compilable. But as you mentioned I am wondering how coding like this would result in anything bad

void* pv=(list<string>)GetIPList();
//something very long processed and processing
list<string> ret=pv;
return ret;