global.cpp

module;

#include "global.hpp"

export module global;

export template <typename T> void output(T item) { dump(item); }

字符串
global.hpp

#include <iostream>

template <typename T> void dump(T val) { std::cout << val << std::endl; }

型
main.cpp

import global;

int main() { output(42); }

型
我编译它：

g++ -fmodules-ts global.cpp main.cpp

型
输出量：

In file included from /usr/include/c++/11/iostream:39,
                 from global.hpp:13,
                 from global.cpp:15,
of module global, imported at main.cpp:13:
/usr/include/c++/11/ostream: In instantiation of ‘std::basic_ostream@global<_CharT, _Traits>& std::endl@global(std::basic_ostream@global<_CharT, _Traits>&) [with _CharT = char; _Traits = std::char_traits@global<char>]’:
global.hpp:15:59:   required from ‘void dump@global(T) [with T = int]’
global.cpp:19:56:   required from ‘void output@global(T) [with T = int]’
main.cpp:15:20:   required from here
/usr/include/c++/11/ostream:685:19: error: ‘flush’ was not declared in this scope
  685 |     { return flush(__os.put(__os.widen('\n'))); }
      |              ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

型
但这是无稽之谈，因为当我编译下面的代码时，一切都很好，它编译得很好：

#include <iostream>

int main() {
   std::cout << "Hello, world!" << std::endl;
}

型
g++有什么问题，我应该如何编译才能让一切正常？