template<template<typename... Ts> typename Tmpl, typename RtrnType,typename... ArgTypes> struct _extract_func_helper_s<Tmpl,RtrnType(ArgTypes...) volatile noexcept> { template<template<typename... Ts> typename Tmpl, typename RtrnType,typename... ArgTypes> struct _extract_func_helper_s<Tmpl,...
= ";constN<factorial(4)>out1;// 在编译时计算volatileintk=8;// 使用 volatile 防止优化std::cout<<k<<"! = "<<factorial(k)<<'\n';// 运行时计算std::cout<<"\"Hello, world!\"里小写字母的个数是 ";constN<countlower("Hello, world!")>out2;// 隐式转换为 conststrconstexprinta[12...
{ std::cout << n << '\n'; } }; int main() { std::cout << "4! = " ; constN<factorial(4)> out1; // 在编译时计算 volatile int k = 8; // 不允许使用 volatile 者优化 std::cout << k << "! = " << factorial(k) << '\n'; // 运行时计算 std::cout << "the ...
const volatile ref-qualifier? & && declarator-id? ...opt id-expressionconst 值const 关键字指定变量的值是常量并通知编译器防止程序员对其进行修改。C++ 复制 // constant_values1.cpp int main() { const int i = 5; i = 10; // C3892 i++; // C2105 } 在...
= ";constN<factorial(4)>out1;// 在编译时计算volatileintk=8;// 不允许使用 volatile 者优化std::cout<<k<<"! = "<<factorial(k)<<'\n';// 运行时计算std::cout<<"the number of lowercase letters in\"Hello, world!\"is ";constN<countlower("Hello, world!")>out2;// 隐式转换到 ...
if (TREE_THIS_VOLATILE (t)) { if (flags & tf_error) error ("expression %qE has side-effects", t); return false; } if (CONSTANT_CLASS_P (t)) return true; switch (TREE_CODE (t)) { case FUNCTION_DECL: case BASELINK: case TEMPLATE_DECL: ...
is_const (C++11) 检查类型是否为 const 限定 (类模板) add_cvadd_constadd_volatile (C++11)(C++11)(C++11) 添加const 或/与 volatile 限定符到给定类型 (类模板) remove_cvremove_constremove_volatile (C++11)(C++11)(C++11) 从给定类型移除 const 或/与 volatile 限定符 (类模板) ...
constexpr std::add_const_t<T>& as_const(T& t) noexcept; (1) (C++17 起) template <class T> void as_const(const T&&) = delete; (2) (C++17 起) 1) 将左值引用组成 t 的const 类型 2) 删除const 右值引用重载,以禁止右值参数 可能的实现 template <class T> constexpr std::add_co...
constexpr std::add_const_t<T>& as_const( T& t ) noexcept; (1) (since C++17) template< class T > void as_const( const T&& ) = delete; (2) (since C++17) 1) Forms lvalue reference to const type of t.2) const rvalue reference overload is deleted to disallow rvalue argument...
= ";constN<factorial(4)>out1;// computed at compile timevolatile int k=8;// disallow optimization using volatilestd::cout<<k<<"! = "<<factorial(k)<<'\n';// computed at run timestd::cout<<"the number of lowercase letters in \"Hello, world!\" is ";constN<countlower("Hello,...