Merge pull request #1059 from luav/example-cp.4

Example CP.4 (task vs thread)

CppCoreGuidelines.md

@@ -13393,7 +13393,13 @@ Application concepts are easier to reason about.
 
 ##### Example
 
-    ???
+    void some_fun() {
+        std::string  msg, msg2;
+        std::thread publisher([&] { msg = "Hello"; });       // bad (less expressive and more error-prone)
+        auto pubtask = std::async([&] { msg2 = "Hello"; });  // OK
+        // ...
+        publisher.join();
+    }
 
 ##### Note