tbodt · February 2, 2020 05:06 · Feb 2, 2020
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,33 @@
+#include <pthread.h>
+#define ATOMIC 1
+
+int flags;
+
+void *thread(void *asdf) {
+    (void) asdf;
+    for (;;) {
+#if ATOMIC
+        __atomic_fetch_or(&flags, 1 << 3, __ATOMIC_SEQ_CST);
+        __atomic_fetch_and(&flags, ~(1 << 3), __ATOMIC_SEQ_CST);
+#else
+        flags |= 1 << 3;
+        flags &= ~(1 << 3);
+#endif
+    }
+    return NULL;
+}
+
+int main() {
+    pthread_t t;
+    pthread_create(&t, NULL, thread, NULL);
+    pthread_detach(t);
+    for (;;) {
+#if ATOMIC
+        __atomic_fetch_or(&flags, 1 << 5, __ATOMIC_SEQ_CST);
+        __atomic_fetch_and(&flags, ~(1 << 5), __ATOMIC_SEQ_CST);
+#else
+        flags |= 1 << 5;
+        flags &= ~(1 << 5);
+#endif
+    }
+}