这段代码不能用
gcc 4.7.0编译：
class Base
{
public:
Base(const Base&) = delete;
};
class Derived : Base
{
public:
Derived(int i) : m_i(i) {}
int m_i;
};
错误是：
c.cpp: In constructor ‘Derived::Derived(int)’: c.cpp:10:24: error: no matching function for call to ‘Base::Base()’ c.cpp:10:24: note: candidate is: c.cpp:4:2: note: Base::Base(const Base&) <deleted> c.cpp:4:2: note: candidate expects 1 argument,0 provided
换句话说,编译器不会为基类生成默认构造函数,而是尝试将已删除的复制构造函数作为唯一可用的重载调用.
这是正常的行为吗？
解决方法
C11§12.1/ 5指出：
A default constructor for a class
Xis a constructor of classXthat can be called without an argument. If there is no user-declared constructor for classX,a constructor having no parameters is implicitly declared as defaulted (8.4).
你的基地(const Base&)=删除;计为用户声明的构造函数,因此它禁止生成隐式默认构造函数.解决方法当然是声明它：
Base() = default;
