c++ - Could not convert from brace initializer list to vector -

i'm observing compilation error "error: not convert '{{{&foo::print_add}, {&x::print}}}' '' 'std::vector'" in below code.

am doing vector insertion wrong? btw don't want use push_back method. possible insert using '='. i'm having feeling it's syntactical mistake not able find it.

when googled, found there bug in earlier versions of gcc. i'm using 4.8.1 i'm assuming library i'm using should include fix.

#include <functional> #include <iostream> #include <vector>  struct foo {   foo(int num) : num_(num) {}   void print_add(int i) const { std::cout << num_+i << '\n'; }   int num_; };  struct x {   void print() {     std::cout << "i'm in x "<<std::endl;   } };  struct xxx {   std::function<void(const foo&,int)> a;   std::function<void(const x&)> b; };  int main() {   std::vector<xxx> vec =    {        {          {&foo::print_add},         {&x::print}     }  }; } 

x::print non-const member function, , therefore pointer cannot used initialize std::function<void(const x&)>.