How to initialize static member array in class with template [duplicate]

Question

Possible Duplicate:
Where and why do I have to put the “template” and “typename” keywords?

#include <iostream>
using namespace std;

template <class T>
class Test
{
    union obj
    {
        union obj* next;
        int num;
    };

    static const int SZ=3;
    static obj* volatile list[SZ];
};

template <class T>
Test<T>::obj* volatile
Test<T>::list[SZ]=
{
    0, 0, 0
};

int main()
{
    return 0;
}

With g++, the error I get is:

18|error: expected constructor, destructor, or type conversion before '*' token

Does it work if you declare that union outside of the class? — rutgersmike
– rutgersmike, Commented Apr 8, 2012 at 4:13
Closing this question is unjustified and unhelpful. Two questions may have the same answer but not be a duplicate. I was searching for how to initialize a static array of a templated class. The apparent duplicate question somewhat assumes I already knew the answer. — Tim MB
– Tim MB, Commented Nov 7, 2012 at 11:52

Cosyn · Accepted Answer · 2012-04-08 04:14:41Z

3

Add the keyword typename before Test<T>::obj* in the definition of the member.

answered Apr 8, 2012 at 4:14

Cosyn

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4 Comments

bames53 Over a year ago

@Potatoswatter I think after the Test<T>::list the names inside Test<T> are in scope. Consider: class A { class B {}; void c(B); }; void A::c(B) {}

Xeo Over a year ago

@bames: You're actually right (sorry if you read my earlier comment). Case in point.

Potatoswatter Over a year ago

@bames53 bah, I deleted my comment about SZ needing qualification before looking it up in the standard. §9.4.2 [class.static.data] says "The initializer expression in the definition of a static data member is in the scope of its class (3.3.7)" but doesn't say anything about the declarator itself. Neither do I see anything under 8.4.2 [dcl.array]. So I think this might be a GCC bug.

Potatoswatter Over a year ago

@bames53: stackoverflow.com/questions/10062156/…

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