Re: template<> compile error

From:
daniel.kruegler@googlemail.com
Newsgroups:
comp.lang.c++.moderated
Date:
Wed, 17 Dec 2008 19:20:20 CST
Message-ID:
<272daace-32d9-4f1f-b94c-d1455d19501a@a12g2000pro.googlegroups.com>
On 17 Dez., 22:36, Coltrane <tendenga...@yahoo.com> wrote:

I am trying to compile some code from the "C++ Programming Language
Special Edition" book and I am getting compiler errors with Visual C++
and g++. The sample code is in appendix C, section C.13.

The code is as follows:

template<class T>
class X{
   static T def_val;
   static T* new_X(T a = def_val);
};

template<class T> T X<T>::def_val(0,0);
template<class T> T* X<T>::new_X(T a) {}


A function with non-void result type is
required to have a return clause. I assume
you wrote

template<class T> T* X<T>::new_X(T a) {return new T(a);}

instead (The book uses the abbreviated notion of
/* ... */ to specify that).

template<> int X<int>::def_val<int> = 0; /*line 10 */
template<> int* X<int>::new_X<int>(int i){} /* line 11 */

I get the following errors with Visual C++

[..]

Indeed these member definitions are invalid and
both compilers are correct to reject the code
(again: I assume a missing return in new_X). The
proper definitions of these so-called explicit
member specializations are:

template<> int X<int>::def_val = 0;
template<> int* X<int>::new_X(int i){/*...*/}

[Note the missing trailing <..>]

HTH & Greetings from Bremen,

Daniel Kr?gler

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