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docs/code-quality/c6396.md

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+---
+description: "Learn more about: Warning C6396: sizeof('integerConstant') always returns the size of the underlying integer type"
+title: Warning C6396
+ms.date: 02/05/2024
+f1_keywords: ["C6396", "SIZEOF_CONSTANT"]
+helpviewer_keywords: ["C6396"]
+---
+# Warning C6396
+
+> sizeof('integerConstant') always returns the size of the underlying integer type
+
+## Remarks
+
+This warning indicates where an integral constant is used as a `sizeof` argument. Such expression always returns the size of the type of the constant. It's better to write `sizeof(type)` instead. This warning catches common typos in buffer offset calculations.
+
+This check ignores character literals because `buffer_size += sizeof(UNICODE_NULL)` is a common idiom.
+
+## Example
+
+```cpp
+void f()
+{  
+    int a = sizeof(5);         // C6396 reported here
+}
+```
+
+To fix this issue, replace the integral constant with its type:
+
+```cpp
+void f()
+{  
+    int a = sizeof(int);         // no C6396 reported here
+}
+```

docs/code-quality/c6397.md

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+---
+description: "Learn more about: Warning C6397: The address-of operator cannot return null pointer in well-defined code"
+title: Warning C6397
+ms.date: 02/05/2024
+f1_keywords: ["C6397", "DUBIOUS_NULL_CHECK"]
+helpviewer_keywords: ["C6397"]
+---
+# Warning C6397
+
+> The address-of operator cannot return `null` pointer in well-defined code
+
+## Remarks
+
+The address-of operator returns the address of its operand. This value should never be compared to `nullptr`:
+* The address-of a field can only be `nullptr` if the base pointer was `nullptr` and the field is at the zero offset (`&p->field == nullptr` implies `p == nullptr`). In this case, the expression should be simplified.
+* In any other cases, the value of the unary `&` operator can't be `nullptr` unless there's undefined behavior in the code (`&v == nullptr` always evaluates to false).
+
+## Example
+
+```cpp
+bool isNull(int *a)
+{  
+    return &a == nullptr; // C6397 reported here.
+}
+```
+
+To fix this issue, double check if the use of unary `&` was intentional:
+
+```cpp
+bool isNull(int *a)
+{  
+    return a == nullptr; // no C6397 reported here.
+}
+```
+
+## See also
+
+[C6398](c6398.md)

docs/code-quality/c6398.md

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+---
+description: "Learn more about: Warning C6398: The address-of a field cannot be null in well-defined code"
+title: Warning C6398
+ms.date: 02/05/2024
+f1_keywords: ["C6398", "DUBIOUS_NULL_CHECK_FIELD"]
+helpviewer_keywords: ["C6398"]
+---
+# Warning C6398
+
+> The address-of a field cannot be `null` in well-defined code
+
+## Remarks
+
+The address-of operator returns the address of its operand. This value should never be compared to `nullptr`:
+* The address-of a field can only be `nullptr` if the base pointer was `nullptr` and the field is at the zero offset (`&p->field == nullptr` implies `p == nullptr`). In this case, the expression should be simplified.
+* In any other cases, the value of the unary `&` operator can't be `nullptr` unless there's undefined behavior in the code (`&v == nullptr` always evaluates to false).
+
+## Example
+
+```cpp
+struct A { int* x; };
+
+bool hasNullField(A *a)
+{  
+    return &a->x == nullptr; // C6398 reported here.
+}
+```
+
+To fix this issue, double check if the use of unary `&` was intentional:
+
+```cpp
+struct A { int* x; };
+
+bool hasNullField(A *a)
+{  
+    return a->x == nullptr; // no C6398 reported here.
+}
+```
+
+## See also
+
+[C6397](c6397.md)

docs/code-quality/toc.yml

@@ -487,6 +487,12 @@ items:
     href: ../code-quality/c6394.md
   - name: Warning C6395
     href: ../code-quality/c6395.md
+  - name: Warning C6396
+    href: ../code-quality/c6396.md
+  - name: Warning C6397
+    href: ../code-quality/c6397.md
+  - name: Warning C6398
+    href: ../code-quality/c6398.md
   - name: Warning C6400
     href: ../code-quality/c6400.md
   - name: Warning C6401