C++11 成员初始化列表歧义

Question

由于此环境中的 GNU 标准库实现，我正在努力解决 c++11 符号解析中似乎存在歧义的问题:

• Arch Linux 4.2.5-1 (x86_64)
• g++ 5.2.0
• clang++ 3.7.0

例子:

#include <iostream>
#include <string>

struct version {

  unsigned major;
  unsigned minor;
  unsigned patch;

  version(unsigned major, unsigned minor, unsigned patch) :
    major(major), minor(minor), patch(patch) { }

  friend std::ostream & operator<<(std::ostream & out, version const& v) {
    out << v.major << ".";
    out << v.minor << ".";
    out << v.patch;
    return out;
  }

};

int main(int argc, char ** argv) {
  version v(1, 1, 0);
  std::cout << v << std::endl;
  return 0;
}

编译器错误:

error: member initializer 'gnu_dev_major' does not name a non-static data
  member or base class
error: member initializer 'gnu_dev_minor' does not name a non-static data
  member or base class

命令:

clang++ -std=c++11 -o test *.cpp

范围解析运算符似乎不适用于成员初始化列表，因此我无法弄清楚如何解决歧义。此示例在没有 c++11 标志的情况下编译良好。

Answer 1

另一种方法是使用大括号:

version(unsigned major, unsigned minor, unsigned patch) :
  major{major}, minor{minor}, patch{patch} { }

那么宏就不会干扰了，因为它们是类函数宏，需要括号才能调用。