// 1 filename:cpp2011-7-5.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
// > 7 Declarations 7.5 Linkage specifications
//
// 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 cpp2011-7-5.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 cpp2011-7-5.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>

using namespace std;

complex sqrt(complex); // C++ linkage by default
extern "C" {
double sqrt(double); // C linkage
}
//
extern "C" void f1(void(*pf)(int));
// the name f1 and its function type have C language
// linkage; pf is a pointer to a C function
extern "C" typedef void FUNC();
FUNC f2; // the name f2 has C++ language linkage and the
// function’s type has C language linkage
extern "C" FUNC f3; // the name of function f3 and the function’s type
// have C language linkage
void (*pf2)(FUNC*); // the name of the variable pf2 has C++ linkage and
// the type of pf2 is pointer to C++ function that
// takes one parameter of type pointer to C function
extern "C" {
static void f4(); // the name of the function f4 has
// internal linkage (not C language
// linkage) and the function’s type
// has C language linkage.
}
extern "C" void f5() {
extern void f4(); // OK: Name linkage (internal)
// and function type linkage (C
// language linkage) gotten from
// previous declaration.
}

void f6() {
extern void f4(); // OK: Name linkage (internal)
// and function type linkage (C
// language linkage) gotten from
// previous declaration.
}
//
extern "C" typedef void FUNC_c();
class C {
void mf1(FUNC_c*); // the name of the function mf1 and the member
// function’s type have C++ language linkage; the
// parameter has type pointer to C function
FUNC_c mf2; // the name of the function mf2 and the member
// function’s type have C++ language linkage
static FUNC_c* q; // the name of the data member q has C++ language
// linkage and the data member’s type is pointer to
// C function
};
extern "C" {
class X {
void mf(); // the name of the function mf and the member
// function’s type have C++ language linkage
void mf2(void(*)()); // the name of the function mf2 has C++ language
// linkage; the parameter has type pointer to
// C function
};
}
int x;
namespace A {
extern "C" int f();
extern "C" int g() { return 1; }
extern "C" int h();
//error: extern "C" int x(); // ill-formed: same name as global-space object x
}
namespace B {
extern "C" int f(); // A::f and B::f refer to the same function
//error: extern "C" int g() { return 1; } // ill-formed, the function g
// with C language linkage has two definitions
}
int A::f() { return 98; } //definition for the function f with C language linkage
extern "C" int h() { return 97; } // definition for the function h with C language linkage
// A::h and ::h refer to the same function
//
//error: extern "C" double f();
static double f(); // error
extern "C" int i; // declaration
extern "C" {
int i; // definition
}
//error: extern "C" static void g(); // error

int main() {
	//
//	cout << f() << std::endl;
	cout << "7 Declarations 7.5 Linkage specifications" << std::endl;
	return 0;
}
// 1 error
// 1.1 c++ -std=c++11 -stdlib=libc++ -Wall cpp2011-7-5.cpp 
cpp2011-7-5.cpp:71:1: error: unknown type name 'complex'; did you mean '_Complex'?
complex sqrt(complex); // C++ linkage by default
^~~~~~~
_Complex
cpp2011-7-5.cpp:71:1: warning: plain '_Complex' requires a type specifier; assuming '_Complex double'
complex sqrt(complex); // C++ linkage by default
^
        double
cpp2011-7-5.cpp:71:14: error: unknown type name 'complex'; did you mean '_Complex'?
complex sqrt(complex); // C++ linkage by default
             ^~~~~~~
             _Complex
cpp2011-7-5.cpp:71:14: warning: plain '_Complex' requires a type specifier; assuming '_Complex double'
complex sqrt(complex); // C++ linkage by default
             ^
                     double
>2 warnings and 2 errors generated