C++11的初始化列表的一个问题,编译错误

C/C++ code

#include<cstdio>#include<functional>#include<vector>#include<memory>using namespace std;struct s{    int i;    s():i(22){printf("ctor\n");}    s(const s&ss){i=ss.i;}    s& operator=(const s&ss){i=ss.i;return *this;}};struct a{    int i;    int j;    int k;};struct c1{    int i;    int j;    int k;    c1( std::initializer_list<int> list ){    }};struct c2: c1    c2( std::initializer_list<int> list )        :c1( list ){    }};struct is{    virtual void f()=0;}constexpr int GetFour(){ return 4; }int main(void){    vector<s> buf(3);    for(s x:buf){        printf("%d\n",x.i);    }    const int i=2;    char pc[i];    short ps[GetFour()];    a a1={1,2,3};    c2 obj{1,2,3};    return 0;}

我在mingw9.0+GCC4.7编译:

////////////////////
D:\>g++ my.cpp
my.cpp:24:2: error: expected '{' before 'c2'
my.cpp:23:1: error: new types may not be defined in a return type
my.cpp:23:1: note: (perhaps a semicolon is missing after the definition of '<typ
e error>')
my.cpp: In function 'int c2(std::initializer_list<int>)':
my.cpp:25:7: error: only constructors take member initializers
my.cpp: At global scope:
my.cpp:27:1: error: expected declaration before '}' token

究竟错在哪里?

[解决办法]
24： struct c2: c1 “{”

31： }“;”