can't use typedef of nested class in template class

[Frank Bergemann]

following doesn't work (gcc-3.4.4)

cat test2.h

template <class Result>
class MyClass
{
private:
class NestedClass
{
public:
typedef int SubType;
} ;
NestedClass::SubType element;
} ;

cat test2.cc

#include "test2.h"

/usr/local/gcc-3.4.4/bin/g++ -c test2.cc

In file included from test2.cc:1:
test2.h:12: error: expected `;' before "element"
When i move NestedClass out, it works:

|padsol05 371cat test2.h
class NestedClass
{
public:
typedef int SubType;
} ;

template <class Result>
class MyClass
{
private:
NestedClass::SubType element;
} ;
???

[Ian Collins]

Frank Bergemann wrote:

following doesn't work (gcc-3.4.4)

>cat test2.h

template <class Result>
class MyClass
{
private:
class NestedClass
{
public:
typedef int SubType;
} ;
NestedClass::SubType element;

You have to tell the compiler NestedClass::SubType is a type:

typename NestedClass::SubType element;

--
Ian Collins.

[Jonathan Mcdougall]

On Dec 12, 2:27 am, Ian Collins <[e-mail]:

Frank Bergemann wrote:

following doesn't work (gcc-3.4.4)

cat test2.h

template <class Result>
class MyClass
{
private:
class NestedClass
{
public:
typedef int SubType;
} ;
NestedClass::SubType element;

You have to tell the compiler NestedClass::SubType is a type:

typename NestedClass::SubType element;

The given example works in Comeau and the FAQ only talks about
nested classes defined in a base class (35.18). As far as I
know, because NestedClass is not a template, there is no need
to do this, although I may be wrong.

--
Jonathan Mcdougall

[James Kanze]

On Dec 12, 8:27 am, Ian Collins <[e-mail]:

Frank Bergemann wrote:

following doesn't work (gcc-3.4.4)

cat test2.h

template <class Result>
class MyClass
{
private:
class NestedClass
{
public:
typedef int SubType;
} ;
NestedClass::SubType element;

You have to tell the compiler NestedClass::SubType is a type:

typename NestedClass::SubType element;

You shouldn't have to. NestedClass is not a dependent type, but
rather a locally defined type, so the compiler knows what is in
it, even without instantiating the template.

--
James Kanze (GABI Software) email:ja*********@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, [phone]

[Frank Bergemann]

- thanks, Ian!
it worked this way.

rgds!

Frank

[Ian Collins]

James Kanze wrote:

On Dec 12, 8:27 am, Ian Collins <[e-mail]:

>Frank Bergemann wrote:

>>following doesn't work (gcc-3.4.4)

>>>cat test2.h
template <class Result>
class MyClass
{
private:
class NestedClass
{
public:
typedef int SubType;
} ;
NestedClass::SubType element;

>You have to tell the compiler NestedClass::SubType is a type:

> typename NestedClass::SubType element;

You shouldn't have to. NestedClass is not a dependent type, but
rather a locally defined type, so the compiler knows what is in
it, even without instantiating the template.

I know, but gcc thinks otherwise!

--
Ian Collins.