// 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 //#include //#include //#include //#include //#include //#include //#include //#include //#include //#include 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(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 ^