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2014/06/16

C++N3242, 2011 (87) 8.5.3 References

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// 1 filename:cpp2011-8-5-3.cpp
// ver 0.1 June.13, 2014
//
// 2 original examples and/or notes:
// (c) ISO/IEC JTC1 SC22 WG21 N3242, April 12, 2011
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf
// > 8 Declarators 8.5 Initializers 8.5.3 References
//
// 3 compile and output mechanism:
// (c) Dr. OGAWA Kiyoshi, kaizen at gifu-u.ac.jp,
//
// 4 compile errors and/or warnings:
// 4.1(c) Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
// Target: x86_64-apple-darwin13.2.0,  Thread model: posix
// Command/Options: c++ -std=c++11 -stdlib=libc++ -Wall cpp2011-8-5-3.cpp 
// (c) LLVM 2003-2009 University of Illinois at Urbana-Champaign.

// 4.2. g++-4.9 (GCC) 4.9.0 20131229 (experimental)
// Copyright (C) 2013 Free Software Foundation, Inc.
// This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// http://gcc.gnu.org/onlinedocs/gcc/Standards.html
// Command/Options: g++-4.9  -std=c++11  -Wall cpp2011-8-5-3.cpp 
// g++-4.9: error: unrecognized command line option '-stdlib=libc++'
// Configuration:brew install gcc49
//
// 4.3. Visual Studio Express 2013, 
// (c) Microsoft http://www.visualstudio.com/
// SPEC:
// Windows 7, .NET Framework
// (c) VMware, Inc.
// VMWare fusion 6
//
// 5. Hardware:  MacBook Pro, 
//(c) Intel http://ark.intel.com/products/37006/
//Core 2 Duo 2.53GHz, 8GB, 1067MHz DDR3
//
// 6. Special Thanks: Upper organizatios and 
// ITSCJ/IPSJ http://www.itscj.ipsj.or.jp/itscj_english/index.html
// Renesas Electronics Corporation.http://www.renesas.com/
// NPO SESSAME project, http://www.sessame.jp/workinggroup/WorkingGroup3/
// Toyo Corporation, http://www.toyo.co.jp/English/
// Japan Standard Association, http://bit.ly/1lzykg1
// NPO TOPPERS project, https://www.toppers.jp/asp-d-download.html
// Daido Universcity, http://www.daido-it.ac.jp/gakubugakka/computer/index.html
// WITZ Co.Ltd., http://www.witz-inc.co.jp/products/solution/solution.html
// SevenWise.co., http://www.7ws.co.jp/index.html
// TOYOTA Motor Corporation, http://toyota.jp/
// IT planning Inc., http://www.itpl.co.jp/en/index.html
// DENSO Corporation, http://www.globaldenso.com/en/
// Aisin Seiki co. Ltd., http://www.aisin.com/
// Spancion Inc., http://www.spansion.com/
// Yazaki Corporation, http://www.yazaki-group.com/global/
// Pananosic Corporation, http://www.panasonic.net/
// SWEST: Summer Workshop on Embedded System Technologies , http://swest.toppers.jp
// CEST: Consortium for Embedded System Technology, http://www.ertl.jp/CEST/
// JUSE: Union of Japanese Scientists and Engineers, http://www.juse.or.jp/e/
// OSC:Open Source Conference, http://www.ospn.jp/

#include <iostream>
//#include <cstdlib>
//#include <string.h>
//#include <cstring>
//#include <type_traits>
//#include <cassert>
//#include <algorithm>
//#include <cmath>
//#include <complex>
//#include <cstddef>
//#include <new>

using namespace std;

int g(int);
void f() {
int i;
int& r = i; // r refers to i
r = 1; // the value of i becomes 1
int* p = &r; // p points to i
int& rr = r; // rr refers to what r refers to, that is, to i
int (&rg)(int) = g; // rg refers to the function g
rg(i); // calls function g
int a[3];
int (&ra)[3] = a; // ra refers to the array a
ra[1] = i; // modifies a[1]
cout << p << rr << std::endl;
}
//
//error: int& r1; // error: initializer missing
extern int& r2; // OK
//
double d = 2.0;
double& rd = d; // rd refers to d
const double& rcd = d; // rcd refers to d
struct A { };
struct B : A { operator int&(); } b;
A& ra = b; // ra refers to A subobject in b
const A& rca = b; // rca refers to A subobject in b
int& ir = B(); // ir refers to the result of B::operator int&
//
//error: double& rd2 = 2.0; // error: not an lvalue and reference not const
int i = 2;
//error: double& rd3 = i; // error: type mismatch and reference not const
//
struct A2 { };
struct B2 : A2 { } b2;
extern B2 f();
const A2& rca2 = f(); // bound to the A subobject of the B rvalue.
A2&& rra = f(); // same as above
struct X {
operator B();
operator int&();
} x;
const A2& r = x; // bound to the A subobject of the result of the conversion
int&& rri = static_cast<int&&>(i); // bound directly to i
B2&& rrb = x; // bound directly to the result of operator B
//error: int&& rri2 = X(); // error: lvalue-to-rvalue conversion applied to the
// result of operator int&
//
const double& rcd2 = 2; // rcd2 refers to temporary with value 2.0
double&& rrd = 2; // rrd refers to temporary with value 2.0
const volatile int cvi = 1;
//error: const int& r2 = cvi; // error: type qualifiers dropped
//error: double&& rrd2 = d; // error: copying lvalue of related type
double&& rrd3 = i; // rrd3 refers to temporary with value 2.0
//
int main() {
cout << d << std::endl;
cout << "8 Declarators 8.5 Initializers 8.5.3 References" << std::endl;
return 0;
}
// 1 error
// 1.1 llvm: c++ -std=c++11 -stdlib=libc++  -Wall cpp2011-8-5-3.cpp 
cpp2011-8-5-3.cpp:106:11: error: functions that differ only in their return type cannot be overloaded
extern B2 f();
          ^
cpp2011-8-5-3.cpp:74:6: note: previous definition is here
void f() {
     ^
cpp2011-8-5-3.cpp:107:11: error: reference to type 'const A2' could not bind to an rvalue of type 'void'
const A2& rca2 = f(); // bound to the A subobject of the B rvalue.
          ^      ~~~
cpp2011-8-5-3.cpp:108:6: error: reference to type 'A2' could not bind to an rvalue of type 'void'
A2&& rra = f(); // same as above
     ^     ~~~
cpp2011-8-5-3.cpp:113:11: error: no viable conversion from 'struct X' to 'const A2'
const A2& r = x; // bound to the A subobject of the result of the conversion
          ^   ~
cpp2011-8-5-3.cpp:104:8: note: candidate constructor (the implicit copy constructor) not viable: no known conversion from 'struct X' to 'const A2 &' for 1st
      argument
struct A2 { };
       ^
cpp2011-8-5-3.cpp:104:8: note: candidate constructor (the implicit move constructor) not viable: no known conversion from 'struct X' to 'A2 &&' for 1st
      argument
struct A2 { };
       ^
cpp2011-8-5-3.cpp:110:1: note: candidate function
operator B();
^
cpp2011-8-5-3.cpp:111:1: note: candidate function
operator int&();
^
cpp2011-8-5-3.cpp:115:6: error: no viable conversion from 'struct X' to 'B2'
B2&& rrb = x; // bound directly to the result of operator B
     ^     ~
cpp2011-8-5-3.cpp:105:8: note: candidate constructor (the implicit copy constructor) not viable: no known conversion from 'struct X' to 'const B2 &' for 1st
      argument
struct B2 : A2 { } b2;
       ^
cpp2011-8-5-3.cpp:105:8: note: candidate constructor (the implicit move constructor) not viable: no known conversion from 'struct X' to 'B2 &&' for 1st
      argument
struct B2 : A2 { } b2;
       ^
cpp2011-8-5-3.cpp:110:1: note: candidate function
operator B();
^
cpp2011-8-5-3.cpp:111:1: note: candidate function
operator int&();
^
>5 errors generated.
//1.2 gcc:  g++-4.9 -std=c++11 -Wall cpp2011-8-5-3.cpp 
cpp2011-8-5-3.cpp:106:13: error: ambiguating new declaration of 'B2 f()'
 extern B2 f();
             ^
cpp2011-8-5-3.cpp:74:6: note: old declaration 'void f()'
 void f() {
      ^
cpp2011-8-5-3.cpp:107:20: error: invalid initialization of reference of type 'const A2&' from expression of type 'void'
 const A2& rca2 = f(); // bound to the A subobject of the B rvalue.
                    ^
cpp2011-8-5-3.cpp:108:14: error: invalid initialization of reference of type 'A2&&' from expression of type 'void'
 A2&& rra = f(); // same as above
              ^
cpp2011-8-5-3.cpp:113:15: error: invalid initialization of reference of type 'const A2&' from expression of type 'X'
 const A2& r = x; // bound to the A subobject of the result of the conversion
               ^
cpp2011-8-5-3.cpp:115:12: error: invalid initialization of reference of type 'B2&&' from expression of type 'X'
 B2&& rrb = x; // bound directly to the result of operator B
            ^


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