Hi,

I am using VC 6.0 on NT machine.

I need to inherit (public inheritance) of vector iterator. The class which
inherit it is a node in a list.
This is redesign of hug application.  The inheritance cause the following
error:

lclist.h(159) : error C2516: 'iterator' : is not a legal base class
        d:\program files\microsoft visual studio\vc98\include\vector(31) :
see declaration of 'iterator'

I examine the vector declaration :   typedef _Tptr iterator;

It's not possible to inherit typdef.

Trying to inherit _Tptr pointed the next typedef of _Tptr A::pointer.
Inheriting A::pointer cause error :

lclist.h(155) : error C2653: 'A' : is not a class or namespace name
lclist.h(156) : error C2504: 'pointer' : base class undefined

Is there any trick to inherit iterator or its a must to use it as a member.


Thanks




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"Itay Sali" <itays@ncc.co.il> writes:

> Hi,
>
> I am using VC 6.0 on NT machine.
>
> I need to inherit (public inheritance) of vector iterator. The class which
> inherit it is a node in a list.
> This is redesign of hug application.  The inheritance cause the following
> error:
>
> lclist.h(159) : error C2516: 'iterator' : is not a legal base class
>         d:\program files\microsoft visual studio\vc98\include\vector(31) :
> see declaration of 'iterator'
>
> I examine the vector declaration :   typedef _Tptr iterator;
>
> It's not possible to inherit typdef.
>
> Trying to inherit _Tptr pointed the next typedef of _Tptr A::pointer.
> Inheriting A::pointer cause error :
>
> lclist.h(155) : error C2653: 'A' : is not a class or namespace name
> lclist.h(156) : error C2504: 'pointer' : base class undefined
>
> Is there any trick to inherit iterator or its a must to use it as a member.

There's no guarantee that vector<T>::iterator is a class.  The
standard permits it to be a typedef for T*, as it is in the
implementation you're using.  (And in several other implementations.)
You can't inherit from pointers, only from classes.

There are some implementations where vector<T>::iterator is a class,
and inheriting from vector<T>::iterator will work on such an
implementation.  Your code won't be portable, though.

As a general piece of advice, I'd recommend that you not try to
inherit from STL iterator classes; you're trying to use the library in
a way that it was not designed for.  There's probably a better way to
do whatever you're doing.

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