template syntax.../ resent

[paul-henri.ferme]

Hi all,

I just hit the following definition in a c++ API:

template <class Str> template <class T, class B>
mysql_ColData<Str>::operator Null<T,B> () const {
if ((*this)[0] == 'N' && (*this)[1] == 'U' &&
(*this)[2] == 'U' && (*this)[3] == 'L' && (*this).size() == 4)
return Null<T,B>(null);
else return Null<T,B>(conv(T()));
}

Is the first line equivalent to
template <class Str, class T, class B> ?

Are both syntax compliant to c++ standards?

cheers

regard

phf

[Jonathan Turkanis]

pa**************@noos.fr wrote:

Hi all,

I just hit the following definition in a c++ API:

template <class Str> template <class T, class B>
mysql_ColData<Str>::operator Null<T,B> () const {
if ((*this)[0] == 'N' && (*this)[1] == 'U' &&
(*this)[2] == 'U' && (*this)[3] == 'L' && (*this).size() == 4)
return Null<T,B>(null);
else return Null<T,B>(conv(T()));
}

Is the first line equivalent to
template <class Str, class T, class B> ?
No, the first is the beginning of the definition of a nested template: the outer
template, a class template mysql_ColData, has a single template parameter Str;
the inner template, a template conversion operator, has two template parameters
T and B.
Are both syntax compliant to c++ standards?
In different contexts, yes.
phf

Jonathan

[paul-henri.ferme]

Jonathan Turkanis wrote:

Thanks for your fast and precise answer...
phf

pa**************@noos.fr wrote:

Hi all,

I just hit the following definition in a c++ API:

template <class Str> template <class T, class B>
mysql_ColData<Str>::operator Null<T,B> () const {
if ((*this)[0] == 'N' && (*this)[1] == 'U' &&
(*this)[2] == 'U' && (*this)[3] == 'L' && (*this).size() == 4)
return Null<T,B>(null);
else return Null<T,B>(conv(T()));
}

Is the first line equivalent to
template <class Str, class T, class B> ?

No, the first is the beginning of the definition of a nested template: the outer
template, a class template mysql_ColData, has a single template parameter Str;
the inner template, a template conversion operator, has two template parameters
T and B.

Are both syntax compliant to c++ standards?

In different contexts, yes.

phf

Jonathan