Template Function Format

[miben@miben.net]

OK, this is tricky. I have a function inside a template that returns a
pointer to a function whose space is declared as, "void
Function(void)" . To declare this, i use:

template <typename Class>
class MyClass {
public:
void SetOnClose(void (Class::*lptnOn Close)(void));
void (Class::*GetOnC lose(void))(voi d);
};

How do you declare the GetOnClose function, above, outside of the
templete?
Currently, i just use the defined function above to do what I need. I
can declare the SetOnClose function outside of the template just fine.

template <typename Class>
class MyClass {
public:
void SetOnClose(void (Class::*lptnOn Close)(void));
void (Class::*GetOnC lose(void))(voi d) {
do stuff here
}
};

template <typename Class>
void Form<Class>::Se tOnClose(void (Class::*lptnOn Close)(void)) {
do stuff here
}

[n2xssvv g02gfr12930]

Re: Template Function Format

miben@miben.net wrote:[color=blue]
> OK, this is tricky. I have a function inside a template that returns a
> pointer to a function whose space is declared as, "void
> Function(void)" . To declare this, i use:
>
> template <typename Class>
> class MyClass {
> public:
> void SetOnClose(void (Class::*lptnOn Close)(void));
> void (Class::*GetOnC lose(void))(voi d);
> };
>
> How do you declare the GetOnClose function, above, outside of the
> templete?
> Currently, i just use the defined function above to do what I need. I
> can declare the SetOnClose function outside of the template just fine.
>
> template <typename Class>
> class MyClass {
> public:
> void SetOnClose(void (Class::*lptnOn Close)(void));
> void (Class::*GetOnC lose(void))(voi d) {
> do stuff here
> }
> };
>
> template <typename Class>
> void Form<Class>::Se tOnClose(void (Class::*lptnOn Close)(void)) {
> do stuff here
> }
>[/color]
Your code is riddled with errors, but I guess this ia the type of thing
you intended:

template <typename Class>
class MyClass
{
private:
void (MyClass::*pfOn Close)(void);
public:
void SetOnClose(void (MyClass::*inp) (void))
{
pfOnClose = inp;
}
void close1(void);
void close2(void);
void close(void)
{
(this->*pfOnClose)( );
}
};

template <typename Class>
void MyClass<Class>: :close1(void)
{
std::cout << "close 1" << std::endl;
}

template <typename Class>
void MyClass<Class>: :close2(void)
{
std::cout << "close 2" << std::endl;
}

void SomeFunction(vo id)
{
MyClass<int> Tmp;
Tmp.SetOnClose( &MyClass<int>:: close1);
Tmp.close();
Tmp.SetOnClose( &MyClass<int>:: close2);
Tmp.close();
}

JB

[John Harrison]

Re: Template Function Format

n2xssvv g02gfr12930 wrote:[color=blue]
> miben@miben.net wrote:
>[color=green]
>> OK, this is tricky. I have a function inside a template that returns a
>> pointer to a function whose space is declared as, "void
>> Function(void)" . To declare this, i use:
>>
>> template <typename Class>
>> class MyClass {
>> public:
>> void SetOnClose(void (Class::*lptnOn Close)(void));
>> void (Class::*GetOnC lose(void))(voi d);
>> };
>>
>> How do you declare the GetOnClose function, above, outside of the
>> templete?
>> Currently, i just use the defined function above to do what I need. I
>> can declare the SetOnClose function outside of the template just fine.
>>
>> template <typename Class>
>> class MyClass {
>> public:
>> void SetOnClose(void (Class::*lptnOn Close)(void));
>> void (Class::*GetOnC lose(void))(voi d) {
>> do stuff here
>> }
>> };
>>
>> template <typename Class>
>> void Form<Class>::Se tOnClose(void (Class::*lptnOn Close)(void)) {
>> do stuff here
>> }
>>[/color]
> Your code is riddled with errors, but I guess this ia the type of thing
> you intended:
>[/color]

How is it riddled with errors? Apart from the misprint of Form for
MyClass is looks fine (and compiles fine).

john

[John Harrison]

Re: Template Function Format

miben@miben.net wrote:[color=blue]
> OK, this is tricky. I have a function inside a template that returns a
> pointer to a function whose space is declared as, "void
> Function(void)" . To declare this, i use:
>
> template <typename Class>
> class MyClass {
> public:
> void SetOnClose(void (Class::*lptnOn Close)(void));
> void (Class::*GetOnC lose(void))(voi d);
> };
>
> How do you declare the GetOnClose function, above, outside of the
> templete?
> Currently, i just use the defined function above to do what I need. I
> can declare the SetOnClose function outside of the template just fine.
>
> template <typename Class>
> class MyClass {
> public:
> void SetOnClose(void (Class::*lptnOn Close)(void));
> void (Class::*GetOnC lose(void))(voi d) {
> do stuff here
> }
> };
>
> template <typename Class>
> void Form<Class>::Se tOnClose(void (Class::*lptnOn Close)(void)) {
> do stuff here
> }
>[/color]

The following code compiler for me, but as soon as I add #include
<iostream> I get an internal compiler error.

This syntax is far too obscure, not only for anyone reading your code
but also it seems for compilers. Be sensible and use a typedef.


struct X
{
void close() {}
};

template <typename Class>
class MyClass {
public:
void SetOnClose(void (Class::*lptnOn Close)(void));
void (Class::*GetOnC lose(void))(voi d);
};

template <typename Class>
void MyClass<Class>: :SetOnClose(voi d (Class::*lptnOn Close)(void)) {
}

template <typename Class>
void (Class::*MyClas s<Class>::GetOn Close(void))(vo id) {
return 0;
}

int main()
{
MyClass<X> x;
x.SetOnClose(&X ::close);
void (X::*ptr)(void) = x.GetOnClose();
}

john

[miben@miben.net]

Re: Template Function Format

ya, i thought that is how i should do it:

template <typename Class>
void (Class::*MyClas s<Class>::GetOn Close(void))(vo id) {
}

I keep getting an internal compile error. typedef sounds like a better
way to do this. It would also make the code much more readable.
typedef inside the class?

[John Harrison]

Re: Template Function Format

miben@miben.net wrote:[color=blue]
> ya, i thought that is how i should do it:
>
> template <typename Class>
> void (Class::*MyClas s<Class>::GetOn Close(void))(vo id) {
> }
>
> I keep getting an internal compile error. typedef sounds like a better
> way to do this. It would also make the code much more readable.
> typedef inside the class?
>[/color]

I think so, this is what I did

#include <iostream>

struct X
{
void close() {}
};

template <typename Class>
class MyClass {
public:
typedef void (Class::*closer )(void);
void SetOnClose(clos er);
closer GetOnClose(void );
};

template <typename Class>
void MyClass<Class>: :SetOnClose(clo ser) {
}

template <typename Class>
typename MyClass<Class>: :closer MyClass<Class>: :GetOnClose(voi d) {
return 0;
}

int main()
{
MyClass<X> x;
x.SetOnClose(&X ::close);
MyClass<X>::clo ser func = x.GetOnClose();
}

BTW g++ 3.4.4 compiles both versions without problems.

john

[miben@miben.net]

Re: Template Function Format

template <typename Class>
class MyClass {
public:
typedef void (Class::*closer )(void);
closer GetOnClose(void );
};

template <typename Class>
typename MyClass<Class>: :closer MyClass<Class>: :GetOnClose(voi d) {
return 0;
}


Very nice job, john.

[miben@miben.net]

Re: Template Function Format

Works great.

template <typename Class>
class Form: public Window {
public:
Form(void);
~Form(void);

void operator =(const Form &frmForm);

typedef void (Class::*m_tdOn Close)(void);
private:
m_tdOnClose m_lptnOnClose;
};

template <typename Class>
typename Form<Class>::m_ tdOnClose Form<Class>::Ge tOnClose(void) {
return m_lptnOnClose;
}

template <typename Class>
void Form<Class>::Se tOnClose(m_tdOn Close lptnOnClose) {
m_lptnOnClose = lptnOnClose;
}