add original source

source/listing_5.6.cpp

@@ -0,0 +1,74 @@
+#include <thread>
+#include <atomic>
+#include <iostream>
+
+std::atomic<int> x(0),y(0),z(0);
+std::atomic<bool> go(false);
+unsigned const loop_count=10;
+
+struct read_values
+{
+    int x,y,z;
+};
+read_values values1[loop_count];
+read_values values2[loop_count];
+read_values values3[loop_count];
+read_values values4[loop_count];
+read_values values5[loop_count];
+void increment(std::atomic<int>* var_to_inc,read_values* values)
+{
+    while(!go)
+        std::this_thread::yield();
+    for(unsigned i=0;i<loop_count;++i)
+    {
+        values[i].x=x.load(std::memory_order_relaxed);
+        values[i].y=y.load(std::memory_order_relaxed);
+        values[i].z=z.load(std::memory_order_relaxed);
+        var_to_inc->store(i+1,std::memory_order_relaxed);
+        std::this_thread::yield();
+    }
+}
+
+void read_vals(read_values* values)
+{
+    while(!go)
+        std::this_thread::yield();
+    for(unsigned i=0;i<loop_count;++i)
+    {
+        values[i].x=x.load(std::memory_order_relaxed);
+        values[i].y=y.load(std::memory_order_relaxed);
+        values[i].z=z.load(std::memory_order_relaxed);
+        std::this_thread::yield();
+    }
+}
+
+void print(read_values* v)
+{
+    for(unsigned i=0;i<loop_count;++i)
+    {
+        if(i)
+            std::cout<<",";
+        std::cout<<"("<<v[i].x<<","<<v[i].y<<","<<v[i].z<<")";
+    }
+    std::cout<<std::endl;
+}
+
+int main()
+{
+    std::thread t1(increment,&x,values1);
+    std::thread t2(increment,&y,values2);
+    std::thread t3(increment,&z,values3);
+    std::thread t4(read_vals,values4);
+    std::thread t5(read_vals,values5);
+    go=true;
+    t5.join();
+    t4.join();
+    t3.join();
+    t2.join();
+    t1.join();
+    print(values1);
+    print(values2);
+    print(values3);
+    print(values4);
+    print(values5);
+}