// 1 filename:cpp2011-14-7-1.cpp // ver 0.1 June.15, 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 // >14 Templates 14.7 Template instantiation and specialization 14.7.1 Implicit instantiation // (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 cpp2011-14-7-1.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 cpp2011-14-7-1.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 #include #include #include using namespace std; template struct Z { void f(); void g(); }; void h() { Z a; // instantiation of class Z required Z* p; // instantiation of class Z not required Z* q; // instantiation of class Z not required a.f(); // instantiation of Z::f() required p->g(); // instantiation of class Z required, and // instantiation of Z::g() required } // template class B { /* ... */ }; template class D : public B { /* ... */ }; void f(void*); void f(B*); void g(D* p, D* pp, D* ppp) { f(p); // instantiation of D required: call f(B*) B* q = pp; // instantiation of D required: // convert D* to B* delete ppp; // instantiation of D required } // template struct S { operator int(); }; void f(int); void f(S&); void f(S); void g(S& sr) { f(sr); // instantiation of S allowed but not required // instantiation of S allowed but not required }; // template class X; //error: X ch; // error: definition of X required // namespace N { template class List { public: T* get(); }; } template class Map { public: N::List lt; V get(K); }; void g(Map& m) { int i = m.get("Nicholas"); } // template void f(T x, T y = ydef(T()), T z = zdef(T())); class A { }; A ydef(A); A zdef(A); void g(A a, A b, A c) { f(a, b, c); // no default argument instantiation f(a, b); // default argument z = zdef(T()) instantiated f(a); // ill-formed; ydef is not declared } // template class X { X* p; // OK X a; // implicit generation of X requires // the implicit instantiation of X which requires // the implicit instantiation of X which ... }; int main() { // cout << "14 Templates 14.7 Template instantiation and specialization 14.7.1 Implicit instantiation" << std::endl; return 0; } // 1 output // c++ -std=c++11 -stdlib=libc++ -Wall cpp2011-14-7-1.cpp cpp2011-14-7-1.cpp:82:12: warning: unused variable 'q' [-Wunused-variable] Z* q; // instantiation of class Z not required ^ cpp2011-14-7-1.cpp:84:1: warning: variable 'p' is uninitialized when used here [-Wuninitialized] p->g(); // instantiation of class Z required, and ^ cpp2011-14-7-1.cpp:81:11: note: initialize the variable 'p' to silence this warning Z* p; // instantiation of class Z not required ^ = nullptr cpp2011-14-7-1.cpp:94:10: warning: unused variable 'q' [-Wunused-variable] B* q = pp; // instantiation of D required: ^ cpp2011-14-7-1.cpp:125:5: warning: unused variable 'i' [-Wunused-variable] int i = m.get("Nicholas"); ^ 4 warnings generated. Undefined symbols for architecture x86_64: "void f(A, A, A)", referenced from: g(A, A, A) in cpp2011-14-7-1-4766d6.o "f(B*)", referenced from: g(D*, D*, D*) in cpp2011-14-7-1-4766d6.o "f(S&)", referenced from: g(S&) in cpp2011-14-7-1-4766d6.o "ydef(A)", referenced from: g(A, A, A) in cpp2011-14-7-1-4766d6.o "zdef(A)", referenced from: g(A, A, A) in cpp2011-14-7-1-4766d6.o "Z::g()", referenced from: h() in cpp2011-14-7-1-4766d6.o "Z::f()", referenced from: h() in cpp2011-14-7-1-4766d6.o "Map::get(char const*)", referenced from: g(Map&) in cpp2011-14-7-1-4766d6.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) // 1.2 gcc: g++-4.9 -std=c++11 -Wall cpp2011-14-7-1.cpp cpp2011-14-7-1.cpp: In function 'void h()': cpp2011-14-7-1.cpp:82:12: warning: unused variable 'q' [-Wunused-variable] Z* q; // instantiation of class Z not required ^ cpp2011-14-7-1.cpp: In function 'void g(D*, D*, D*)': cpp2011-14-7-1.cpp:94:10: warning: unused variable 'q' [-Wunused-variable] B* q = pp; // instantiation of D required: ^ cpp2011-14-7-1.cpp: In function 'void g(Map&)': cpp2011-14-7-1.cpp:125:5: warning: unused variable 'i' [-Wunused-variable] int i = m.get("Nicholas"); ^ cpp2011-14-7-1.cpp: In function 'void h()': cpp2011-14-7-1.cpp:84:7: warning: 'p' may be used uninitialized in this function [-Wmaybe-uninitialized] p->g(); // instantiation of class Z required, and ^ Undefined symbols for architecture x86_64: "void f(A, A, A)", referenced from: g(A, A, A) in ccigpdYG.o "f(B*)", referenced from: g(D*, D*, D*) in ccigpdYG.o "f(S&)", referenced from: g(S&) in ccigpdYG.o "ydef(A)", referenced from: g(A, A, A) in ccigpdYG.o "zdef(A)", referenced from: g(A, A, A) in ccigpdYG.o "Z::g()", referenced from: h() in ccigpdYG.o "Z::f()", referenced from: h() in ccigpdYG.o "Map::get(char const*)", referenced from: g(Map&) in ccigpdYG.o ld: symbol(s) not found for architecture x86_64 collect2: error: ld returned 1 exit status