problem in static function template specialization

[Marco Jez]

The following code reproduces a problem I'm having with the GCC compiler. It
compiles fine on MSVC, so I'm wondering whether it is legal C++ code or not.

template<typename C>
struct Provider
{
template<typename T>
static void func() {}
};

template<typename C, typename Pro>
struct Client
{
void create()
{
Pro::func<C>(); // compiler stops here
}
};

int main()
{
Client<int, Provider<double> > cli;
cli.create();
return 0;
}


The GNU compiler gives me a "parse error" at this line:

Pro::func<C>();

Note that if parameter T in Provider::func() was deducible automatically
(for example through a function argument), the code would compile. It seems
that the explicit template specialization above confuses the compiler.

Am I doing something wrong?

Cheers,
Marco

 

[Malte Starostik]

The following code reproduces a problem I'm having with the GCC compiler. It
compiles fine on MSVC, so I'm wondering whether it is legal C++ code or not.

template<typename C>
struct Provider
{
template<typename T>
static void func() {}
};

template<typename C, typename Pro>
struct Client
{
void create()
{
Pro::func<C>(); // compiler stops here

}
};

int main()
{
Client<int, Provider<double> > cli;
cli.create();
return 0;
}


The GNU compiler gives me a "parse error" at this line:

Pro::func<C>();

Note that if parameter T in Provider::func() was deducible automatically
(for example through a function argument), the code would compile. It seems
that the explicit template specialization above confuses the compiler.

Am I doing something wrong?

See above. Similarly to the required use of typename with dependent
types (see the recent "trying to declare an iterator for a std::vector
of template pointers" thread), you have to explicitly tell the compiler
that Pro::foo is a template function here.

HTH,
Malte

 

[Victor Bazarov]

The following code reproduces a problem I'm having with the GCC
compiler. It compiles fine on MSVC, so I'm wondering whether it is
legal C++ code or not.
template<typename C>
struct Provider
{
template<typename T>
static void func() {}
};

template<typename C, typename Pro>
struct Client
{
void create()
{
Pro::func<C>(); // compiler stops here

I think you need

Pro::template func<C>();

here.

}
};

int main()
{
Client<int, Provider<double> > cli;
cli.create();
return 0;
}


The GNU compiler gives me a "parse error" at this line:

Pro::func<C>();

Note that if parameter T in Provider::func() was deducible
automatically (for example through a function argument), the code
would compile. It seems that the explicit template specialization
above confuses the compiler.
Am I doing something wrong?

Missing the 'template' keyword. See above.

V

 

[Marco Jez]

I think you need

Pro::template func<C>();

here.

Thanks Victor and Malte. I must admit I've never seen this syntax before...


Cheers,
Marco