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--- os_cp:find_out_what_is_going_on2 [2024/04/17 21:33] – utworzono jkonczak
+++ os_cp:find_out_what_is_going_on2 [2026/04/27 22:29] (current) – jkonczak
@@ Line 22: / Line 22: @@
 volatile char *const a = data + 64;
 volatile char *const b = data + 64 * 2;
-atomic_char vA, vB, control;
+atomic_char vA, vB, barrier;
 void *th1(void *arg) {
-  control++;
+  barrier++;
-  while (control != 2);
+  while (barrier != 2);
   *b = 1;
@@ Line 35: / Line 35: @@
 void *th2(void *arg) {
-  control++;
+  barrier++;
-  while (control != 2);
+  while (barrier != 2);
-  volatile int dummy = 44;
-  while (dummy--);
   *a = 1;
@@ Line 58: / Line 55: @@
 </code>
 <html></div></html>
+++++ C++ version of the code |
+Compile with: \\
+<code bash>g++ -g -O0 sb.cpp -o sb</code>
+<html><div style="line-height:1em"></html>
+<code cpp sb.cpp>
+#include <cstdio>
+#include <future>
+#include <atomic>
+volatile char data[64 * 3];
+volatile char &a = data[64];
+volatile char &b = data[64*2];
+std::atomic<int_fast8_t> barrier;
+char th1() {
+    char vA;
+    barrier++;
+    while (barrier != 2);
+    b = 1;
+    vA = a;
+    return vA;
+}
+char th2() {
+    char vB;
+    barrier++;
+    while (barrier != 2);
+    a = 1;
+    vB = b;
+    return vB;
+}
+int main() {
+    auto a1 = std::async(th1);
+    auto a2 = std::async(th2);
+    char vA = a1.get();
+    char vB = a2.get();
+    printf("%d %d\n", vA, vB);
+    return 0;
+}
+</code>
+<html></div></html>
+++++