// C++N4606 Committee Draft, Standard for Programming Language C++
// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4606.pdf
#define msg "C++N460(271) 29.3 Order and consistency [atomics.order]p1331.cpp"
// Edited by Dr. Ogawa Kiyoshi. Compile procedure and results record.

#include <iostream>
#include <cstdlib>
#include <atomic>
#include <thread>
int data;
std::atomic<bool> ready(false);
std::atomic<bool> y(false);
std::atomic<bool> x(false);
std::atomic<bool> r1(false);
std::atomic<bool> r2(false);

//https://cpprefjp.github.io/reference/atomic/memory_order.html

void f()
{
  while (!ready.load(std::memory_order_acquire)) {
  }

  std::cout << " data ="<<data << std::endl;   // (2)
}
void f2() {

// Thread 1:
  r1 = y.load(std::memory_order_relaxed);
  x.store(r1, std::memory_order_relaxed);
  std::cout << " r1="<<r1 << std::endl;
}
void f3() {
// Thread 2:
  r2 = x.load(std::memory_order_relaxed);
  y.store(r2, std::memory_order_relaxed);
  std::cout << " r2="<<r2 << std::endl;
}
int main()
{
  std::thread t(f);
  std::thread t2(f2);
  std::thread t3(f3);
  data = 3;   // (1)
  ready.store(true, std::memory_order_release);

  t.join();
  t2.join();
  t3.join();

  std::cout<< msg << std::endl;
  return EXIT_SUCCESS;
}

$ ./cppall.sh p1331
$ clang++ p1331.cpp -std=c++03 -Wall
 data = r1= r2=300


C++N460(271) 29.3 Order and consistency [atomics.order]p1331.cpp
$ clang++ p1331.cpp -std=c++11 -Wall
 data = r1= r2=300


C++N460(271) 29.3 Order and consistency [atomics.order]p1331.cpp
$ clang++ p1331.cpp -std=c++17 -Wall
 data = r1= r2=300


C++N460(271) 29.3 Order and consistency [atomics.order]p1331.cpp

$ g++-7 p1331.cpp -std=c++03  -Wall
In file included from /usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/atomic:38:0,
                 from p1331.cpp:8:
/usr/local/Cellar/gcc/7.3.0_1/include/c++/7.3.0/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
 #error This file requires compiler and library support \
  ^~~~~
p1331.cpp:11:6: error: 'atomic' in namespace 'std' does not name a template type
 std::atomic<bool> ready(false);
      ^~~~~~
p1331.cpp:12:6: error: 'atomic' in namespace 'std' does not name a template type
 std::atomic<bool> y(false);
      ^~~~~~
p1331.cpp:13:6: error: 'atomic' in namespace 'std' does not name a template type
 std::atomic<bool> x(false);
      ^~~~~~
p1331.cpp:14:6: error: 'atomic' in namespace 'std' does not name a template type
 std::atomic<bool> r1(false);
      ^~~~~~
p1331.cpp:15:6: error: 'atomic' in namespace 'std' does not name a template type
 std::atomic<bool> r2(false);
      ^~~~~~
p1331.cpp: In function 'void f()':
p1331.cpp:21:11: error: 'ready' was not declared in this scope
   while (!ready.load(std::memory_order_acquire)) {
           ^~~~~
p1331.cpp:21:11: note: suggested alternative: 'fread'
   while (!ready.load(std::memory_order_acquire)) {
           ^~~~~
           fread
p1331.cpp:21:27: error: 'memory_order_acquire' is not a member of 'std'
   while (!ready.load(std::memory_order_acquire)) {
                           ^~~~~~~~~~~~~~~~~~~~
p1331.cpp: In function 'void f2()':
p1331.cpp:29:1: error: 'r1' was not declared in this scope
 r1 = y.load(std::memory_order_relaxed);
 ^~
p1331.cpp:29:6: error: 'y' was not declared in this scope
 r1 = y.load(std::memory_order_relaxed);
      ^
p1331.cpp:29:18: error: 'memory_order_relaxed' is not a member of 'std'
 r1 = y.load(std::memory_order_relaxed);
                  ^~~~~~~~~~~~~~~~~~~~
p1331.cpp:30:1: error: 'x' was not declared in this scope
 x.store(r1, std::memory_order_relaxed);
 ^
p1331.cpp:30:18: error: 'memory_order_relaxed' is not a member of 'std'
 x.store(r1, std::memory_order_relaxed);
                  ^~~~~~~~~~~~~~~~~~~~
p1331.cpp: In function 'void f3()':
p1331.cpp:35:1: error: 'r2' was not declared in this scope
 r2 = x.load(std::memory_order_relaxed);
 ^~
p1331.cpp:35:1: note: suggested alternative: 'f2'
 r2 = x.load(std::memory_order_relaxed);
 ^~
 f2
p1331.cpp:35:6: error: 'x' was not declared in this scope
 r2 = x.load(std::memory_order_relaxed);
      ^
p1331.cpp:35:18: error: 'memory_order_relaxed' is not a member of 'std'
 r2 = x.load(std::memory_order_relaxed);
                  ^~~~~~~~~~~~~~~~~~~~
p1331.cpp:36:1: error: 'y' was not declared in this scope
 y.store(r2, std::memory_order_relaxed);
 ^
p1331.cpp:36:18: error: 'memory_order_relaxed' is not a member of 'std'
 y.store(r2, std::memory_order_relaxed);
                  ^~~~~~~~~~~~~~~~~~~~
p1331.cpp: In function 'int main()':
p1331.cpp:41:8: error: 'thread' is not a member of 'std'
   std::thread t(f);
        ^~~~~~
p1331.cpp:42:8: error: 'thread' is not a member of 'std'
   std::thread t2(f2);
        ^~~~~~
p1331.cpp:43:8: error: 'thread' is not a member of 'std'
   std::thread t3(f3);
        ^~~~~~
p1331.cpp:45:3: error: 'ready' was not declared in this scope
   ready.store(true, std::memory_order_release);
   ^~~~~
p1331.cpp:45:3: note: suggested alternative: 'fread'
   ready.store(true, std::memory_order_release);
   ^~~~~
   fread
p1331.cpp:45:26: error: 'memory_order_release' is not a member of 'std'
   ready.store(true, std::memory_order_release);
                          ^~~~~~~~~~~~~~~~~~~~
p1331.cpp:47:3: error: 't' was not declared in this scope
   t.join();
   ^
p1331.cpp:48:3: error: 't2' was not declared in this scope
   t2.join();
   ^~
p1331.cpp:48:3: note: suggested alternative: 'f2'
   t2.join();
   ^~
   f2
p1331.cpp:49:3: error: 't3' was not declared in this scope
   t3.join();
   ^~
p1331.cpp:49:3: note: suggested alternative: 'f3'
   t3.join();
   ^~
   f3

$ g++-7 p1331.cpp -std=c++11  -Wall
 data = r1= r2=300


C++N460(271) 29.3 Order and consistency [atomics.order]p1331.cpp

$ g++-7 p1331.cpp -std=c++17  -Wall
 r2= data = r1=300


C++N460(271) 29.3 Order and consistency [atomics.order]p1331.cpp