Question

当我遇到绊脚石的时候，我只是在探索C ++ 0x中的一些新东西：

#include <list>
#include <cstdio>
using namespace std;

template <typename T,typename F>
void ForEach (list<T> l, F f) {
    for (typename list<T>::iterator it=l.begin();it!=l.end();++it)
        f(*it);
}

int main() {
    int arr[] = {1,2,3,4,5,6};
    list<int> l (arr,arr+6);
    ForEach(l,[](int x){printf("%d\n",x);});
}

无法编译。我得到一堆未定义的符号错误。这是make的输出：

 i386-apple-darwin9-gcc-4.5.0 -std=c++0x -I/usr/local/include -o func main.cpp
Undefined symbols:
  "___cxa_rethrow", referenced from:
      std::_List_node<int>* std::list<int, std::allocator<int> >::_M_create_node<int const&>(int const&&&) in ccPxxPwU.o
  "operator new(unsigned long)", referenced from:
      __gnu_cxx::new_allocator<std::_List_node<int> >::allocate(unsigned long, void const*) in ccPxxPwU.o
  "___gxx_personality_v0", referenced from:
      ___gxx_personality_v0$non_lazy_ptr in ccPxxPwU.o
  "___cxa_begin_catch", referenced from:
      std::_List_node<int>* std::list<int, std::allocator<int> >::_M_create_node<int const&>(int const&&&) in ccPxxPwU.o
  "operator delete(void*)", referenced from:
      __gnu_cxx::new_allocator<std::_List_node<int> >::deallocate(std::_List_node<int>*, unsigned long) in ccPxxPwU.o
  "___cxa_end_catch", referenced from:
      std::_List_node<int>* std::list<int, std::allocator<int> >::_M_create_node<int const&>(int const&&&) in ccPxxPwU.o
  "std::__throw_bad_alloc()", referenced from:
      __gnu_cxx::new_allocator<std::_List_node<int> >::allocate(unsigned long, void const*) in ccPxxPwU.o
  "std::_List_node_base::_M_hook(std::_List_node_base*)", referenced from:
      void std::list<int, std::allocator<int> >::_M_insert<int const&>(std::_List_iterator<int>, int const&&&) in ccPxxPwU.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [func] Error 1

为什么这不起作用？

Answer 1

这些是链接错误。你错过了一个C ++库吗？如果您使用i386-apple-darwin9-g++-4.5.0怎么办？

P.S。我无法测试这个，因为我的Mac上有gcc 4.2.1（i686-apple-darwin10-gcc-4.2.1）并获得：

cc1plus: error: unrecognized command line option "-std=c++0x"

C ++ 0x lambdas的未定义符号？

1 个答案: