gcc cant support this ??

[William.Zhang]

the following code:

template <class T>
class test{
typedef T::XXX x;
};

int main(){
return 0;
}
Cant be compiled by mingw (but can by borland c++ 5.5) .
Cant gcc support this ?

[Phlip]

William.Zhang wrote:

template <class T>
class test{
typedef T::XXX x;
};

int main(){
return 0;
} Cant be compiled by mingw (but can by borland c++ 5.5) .
Cant gcc support this ?

What error message do you get? What line does it point to?

I don't fully understand 'typename', but you can try that instead of
'class'...

--
Phlip
http://c2.com/cgi/wiki?ZeekLand <-- NOT a blog!!!

[Ian Collins]

William.Zhang wrote:

the following code:

template <class T>
class test{
typedef T::XXX x;
change to typedef typename T::XXX x;
};

int main(){
return 0;
}
Cant be compiled by mingw (but can by borland c++ 5.5) .
Cant gcc support this ?

In my opinion, it shouldn't be compiling an unused template...

--
Ian Collins.

[Kai-Uwe Bux]

William.Zhang wrote:

the following code:

template <class T>
class test{
typedef T::XXX x;
This should read:

typedef typename T::XXX x;

The compiler is not entitled to assume that T::XXX is a typename, so it has
to be told.
};

int main(){
return 0;
}
Cant be compiled by mingw (but can by borland c++ 5.5) .
Cant gcc support this ?

Your code is in error, g++ is correct.
Best

Kai-Uwe Bux

[Noah Roberts]

Ian Collins wrote:

William.Zhang wrote:

Cant be compiled by mingw (but can by borland c++ 5.5) .
Cant gcc support this ?

In my opinion, it shouldn't be compiling an unused template...

Yeah, that's a pretty serious violation of the standard.

[William.Zhang]

this is OK:
typedef typename T::XXX x;

gcc is strict to c++.

"Phlip" <ph******@yahoo.com> дÈëÏûÏ¢ÐÂÎÅ:JC*******************@newssvr21.news. prodigy.com...

William.Zhang wrote:

template <class T>
class test{
typedef T::XXX x;
};

int main(){
return 0;
}

Cant be compiled by mingw (but can by borland c++ 5.5) .
Cant gcc support this ?

What error message do you get? What line does it point to?

I don't fully understand 'typename', but you can try that instead of
'class'...

--
Phlip
http://c2.com/cgi/wiki?ZeekLand <-- NOT a blog!!!

[Michiel.Salters]

Noah Roberts wrote:

Ian Collins wrote:

William.Zhang wrote:

Cant be compiled by mingw (but can by borland c++ 5.5) .
Cant gcc support this ?

In my opinion, it shouldn't be compiling an unused template...

Yeah, that's a pretty serious violation of the standard.

Instantiating it would be a violation. Compiling it is mandatory. This
is the reason
we talk about two-phase name lookup for templates, in both phases name
lookup
happens. 'typename' is needed here (as others have shown) because it
tells the
compiler in phase 1 (compilation) what the results of phase 2
(instantiation) will be.

HTH,
Michiel Salters

[Ian Collins]

Mi*************@tomtom.com wrote:

Noah Roberts wrote:

Ian Collins wrote:

William.Zhang wrote:

Cant be compiled by mingw (but can by borland c++ 5.5) .
Cant gcc support this ?
In my opinion, it shouldn't be compiling an unused template...

Yeah, that's a pretty serious violation of the standard.

Instantiating it would be a violation. Compiling it is mandatory. This
is the reason
we talk about two-phase name lookup for templates, in both phases name
lookup
happens. 'typename' is needed here (as others have shown) because it
tells the
compiler in phase 1 (compilation) what the results of phase 2
(instantiation) will be.

Can you point me at the appropriate part of the standard? I've never
been 100% sure what the compiler should do with unused templates, beyond
checking they are well formed.

--
Ian Collins.