Function call_impl

cpp-subprocess/subprocess.hpp:2166–2169

  template<typename F, typename... Args>
  int call_impl(F& farg, Args&&... args)
  {
    return Popen(std::forward<F>(farg), std::forward<Args>(args)...).wait();
  }

  static inline void pipeline_impl(std::vector<Popen>& cmds)
  {