值类型(value categories) 每一个C++表达式(带有运算对象[operand]的运算符、字面值[literal]、变量名等)都是由两个独立的属性(properties) ——— 型别[type]和值类型[value categories] ——— 来描述[characterized]的。每一个表达式都有某些非引用类型[non-reference type],并且每一个表达式都明确地属于下面三...
参考文献https://en.cppreference.com/右值引用是C++11中最重要的新特性之一，它解决了C++中大量的历史...
Value Category 自C++11引入的将亡值(xvalue, expiring, ex开头的字母的缩写通常是x)概念,每个人第一眼看到下图都会懵圈,表达式(Expression)分为泛左值(glvaue, general)和右值(rvalue)两大类,泛左值分为左值(lvaue, left)和将亡值,右值分为将亡值和纯右值(prvalue, pure)。 这些分类有一个统称的名字--V...
a.m, the member of object expression, where m is a member enumerator or a non-static member function[2], or where a is an rvalue and m is a non-static data member of non-reference type (until C++11);(内建.运算符,m可以是枚举或者成员函数,在C++11还可以是纯右值) p->m, the built...
a cast expression to lvalue reference type, such asstatic_cast<int&>(x)orstatic_cast<void(&)(int)>(x); a non-typetemplate parameterof an lvalue reference type; template<int&v>voidset(){v=5;// template parameter is lvalue}inta{3};// static variable, fixed address is known at compil...
#include <iostream> #include <type_traits> class A {}; static_assert ( std::is_rvalue_reference_v<A> == false and std::is_rvalue_reference_v<A&> == false and std::is_rvalue_reference_v<A&&> != false and std::is_rvalue_reference_v<char> == false and std::is_rvalue_ref...
问const_reference_type未编译，但常量value_type&编译ENDescription 编译器在对程序进行编译之前，首先要...
test.cpp (15) : error C2248: 'MyRefType::operator =' : cannot access private member declared in class 'MyRefType' meow.cpp (5) : see declaration of 'MyRefType::operator =' meow.cpp (3) : see declaration of 'MyRefType' Value types and move efficiency Copy allocation overhead is...
// allocator_value_type.cpp // compile with: /EHsc #include <memory> #include <iostream> #include <vector> using namespace std; int main( ) { vector <double> v; vector <double> ::iterator vIter, vfIter; vector <double> :: allocator_type vAlloc; int j; for ( j = 1 ; j <= ...
right.cpp:11:25: error: invalid initialization of non-constreference of type ‘int&’froman rvalue of type ‘int’int& val =getValue();^root@ubuntu:~/c++# 1. 2. 3. 4. 5. 6. #include <iostream>intgetValue () {intii =10;returnii; ...