Merge pull request MicrosoftDocs#2404 from JordanMaples/patch-24

Colin Robertson · web-flow · commit 0b9599918e89 · 2020-08-20T16:53:03.000-07:00
Add example for C26402
diff --git a/docs/code-quality/c26402.md b/docs/code-quality/c26402.md
@@ -1,11 +1,44 @@
 ---
 title: C26402
-ms.date: 09/04/2019
+ms.date: 08/20/2020
 ms.topic: "conceptual"
 f1_keywords: ["C26402"]
 helpviewer_keywords: ["C26402"]
 ms.assetid: b9d3d398-697a-4a5d-8bfe-9c667dffb90b
 ---
 # C26402 DONT_HEAP_ALLOCATE_MOVABLE_RESULT
 
-To avoid confusion about whether a pointer owns an object, a function that returns a movable object should allocate it on the stack and return it by value instead of returning a heap-allocated object. If pointer semantics are required, then return a smart pointer instead of a raw pointer. See [C++ Core Guidelines R.3](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Rr-ptr): *Warn if a function returns an object that was allocated within the function but has a move constructor. Suggest considering returning it by value instead.*
+> `Return a scoped object instead of a heap-allocated if it has a move constructor (r.3).`
+
+## Remarks
+
+To avoid confusion about whether a pointer owns an object, a function that returns a movable object should allocate it on the stack. It should then return the object by value instead of returning a heap-allocated object. If pointer semantics are required, return a smart pointer instead of a raw pointer. For more information, see [C++ Core Guidelines R.3](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#Rr-ptr): *Warn if a function returns an object that was allocated within the function but has a move constructor. Suggest considering returning it by value instead.*
+
+## Example
+
+This example shows a function, `bad_example`, that raises warning C26409. It also shows how function `good_example` doesn't cause this issue.
+
+```cpp
+// C26402.cpp
+
+struct S
+{
+    S() = default;
+    S(S&& s) = default;
+};
+
+S* bad_example()
+{
+    S* s = new S(); // C26409, avoid explicitly calling new.
+    // ... 
+    return s; // C26402
+}
+
+// Prefer returning objects with move contructors by value instead of unnecessarily heap-allocating the object.
+S good_example() noexcept
+{
+    S s;
+    // ...
+    return s;
+}
+```
