Repo sync for protected branch

docs/assembler/masm/extern-masm.md

@@ -1,9 +1,8 @@
 ---
-description: "Learn more about: EXTERN"
+description: "Learn more about the MASM directive: EXTERN"
 title: "EXTERN (MASM)"
-ms.date: "12/06/2019"
+ms.date: 1/10/2025
 helpviewer_keywords: ["EXTERN directive"]
-ms.assetid: 667d703d-3aaf-4139-a586-29bc5dab1aff
 ---
 # EXTERN
 
@@ -17,9 +16,9 @@ Defines one or more external variables, labels, or symbols called *name* whose t
 
 The *language-type* argument is valid in 32-bit MASM only.
 
-The *type* can be [ABS](operator-abs.md), which imports *name* as a constant. Same as [EXTRN](extrn.md).
+The *type* can be [`ABS`](operator-abs.md), which imports *name* as a constant. Same as [`EXTRN`](extrn.md).
 
-The *type* can also be PROC, in which case *name* is treated as an external procedure.
+The *type* can also be [`PROC`](proc.md), in which case *name* is treated as an external procedure.
 
 ## See also
 

docs/c-runtime-library/link-options.md

@@ -7,9 +7,9 @@ ms.assetid: 05b5a77b-9dd1-494b-ae46-314598c770bb
 ---
 # Link options
 
-The CRT lib directory includes several small object files that enable specific CRT features without any code change. These object files are called "link options" since you only have to add them to the linker command line to use them.
+The CRT lib directory includes several small object files that enable specific CRT features without code changes. These object files are called "link options" because you only have to add them to the linker command line to use them. To do this from Visual Studio, in the Solution Explorer right-click your project and choose **Properties**. Under **Configuration Properties**, choose **Linker** > **Input** > **Additional Dependencies** and specify the additional items to add to the link command line.
 
-CLR pure mode versions of these objects are deprecated in Visual Studio 2015 and unsupported in Visual Studio 2017. Use the regular versions for native and /clr code.
+CLR pure mode versions of these objects are deprecated in Visual Studio 2015 and unsupported in Visual Studio 2017. Use the regular versions for native and `/clr` code.
 
 | Native and /clr | Pure mode | Description |
 |---|---|---|

docs/code-quality/c26831.md

@@ -58,4 +58,6 @@ void foo(int i, int j)
 ## See also
 
 [`C26832`](c26832.md)\
-[`C26833`](c26833.md)
+[`C26833`](c26833.md)\
+[`C26838`](c26838.md)\
+[`C26839`](c26839.md)

docs/code-quality/c26838.md

@@ -0,0 +1,62 @@
+---
+title: Warning C26838
+description: Learn about Microsoft C++ code analysis warning C26838.
+author: Rastaban
+ms.author: philc
+ms.topic: reference
+ms.date: 1/10/2025
+---
+# Warning C26838
+
+> Allocation size is the result of a signed to unsigned narrowing conversion that could result in overflow if the signed value is negative.
+
+This warning was added in Visual Studio 2022 version 17.13.
+
+## Remarks
+
+Reports that the size specified for an allocation may be the result of the conversion of a possibly negative signed value to an unsigned value. For example:
+
+```cpp
+void* CustomAlloc(size_t);
+
+int* CreateIntArray(int numberOfElements)
+{
+    int* p = (int*)CustomAlloc(numberOfElements * sizeof(int)); // Warning: C26838
+
+    return p;
+}
+```
+
+The expression `numberOfElements * sizeof(int)`, `numberOfElements` is signed and `sizeof(int)` is unsigned. On 64-bit machines, `numberOfElements` is promoted to an unsigned value when multiplied
+by `sizeof(int)`. When `numberOfElements` is negative, the resulting value may overflow or have unexpected results when passed to `CustomAlloc`.
+
+This check applies to common allocation functions like `new`, `malloc`, and `VirtualAlloc`. The check also applies to custom allocator functions that have `alloc` (case insensitive) in the function name.
+
+This check sometimes fails to recognize that certain checks can prevent overflows because the check is conservative.
+
+## Example
+
+To fix the previous code example in which `numberOfElements * sizeof(int)` might overflow due to a negative signed value, introduce a check to ensure it won't. For example:
+
+```cpp
+void* CustomAlloc(size_t);
+
+int* CreateIntArray(int numberOfElements)
+{
+    if (numberOfElements < 0)
+        return nullptr;
+
+    int* p = (int*)CustomAlloc(numberOfElements * sizeof(int));
+    // ...
+    return p;
+}
+```
+
+In the previous example, checking for a negative value addresses the `C26832` warning. Depending on the size of the types involved, this check may result in a different warning such as [`C26831`](c26831.md). For example, on a 32-bit system, both `int` and `size_t` are 32 bits, so the result of the multiplication can still overflow without negative values.
+
+## See also
+
+[`C26831`](c26831.md)\
+[`C26832`](c26832.md)\
+[`C26833`](c26833.md)\
+[`C26833`](c26839.md)

docs/code-quality/c26839.md

@@ -0,0 +1,53 @@
+---
+title: Warning C26839
+description: Learn about Microsoft C++ code analysis warning C26839.
+author: Rastaban
+ms.author: philc
+ms.topic: reference
+ms.date: 1/10/2025
+---
+# Warning C26839
+
+> Array new allocation size is the result of a signed to unsigned narrowing conversion that could result in overflow if the signed value is negative.
+
+This warning was added in Visual Studio 2022 version 17.13.
+
+## Remarks
+
+Reports that the size specified for an array `new` allocation may be the result of the conversion of a possibly negative signed value to an unsigned value. For example:
+
+```cpp
+int* CreateIntArray(int size)
+{
+    int* intArray = new int[size];
+    return intArray;
+}
+```
+
+The expression `new int[size]`, `size` is signed. The compiler converts the signed value to an unsigned value to calculate how many bytes to be allocated for the array. When `size` is negative, the result of that calculation may overflow or have unexpected results when passed to `new`.
+
+This check is the same as [`C26838`](c26838.md), but applies only to `new T[]`.
+
+This check sometimes fails to recognize that certain checks can prevent overflows because the check is conservative.
+
+## Example
+
+To fix the previous code example in which the size calculation might overflow due to a negative signed value, introduce a check to ensure it won't. For example:
+
+```cpp
+int* CreateIntArray(int size)
+{
+    if (size < 0)
+        return nullptr;
+
+    int* intArray = new int[size];
+    return intArray;
+}
+```
+
+## See also
+
+[`C26831`](c26831.md)\
+[`C26832`](c26832.md)\
+[`C26838`](c26833.md)\
+[`C26838`](c26838.md)

docs/code-quality/toc.yml

@@ -633,6 +633,10 @@ items:
     href: ../code-quality/c26830.md
   - name: Warning C26831
     href: ../code-quality/c26831.md
+  - name: Warning C26838
+    href: c26838.md
+  - name: Warning C26839
+    href: c26839.md
   - name: Warning C26832
     href: ../code-quality/c26832.md
   - name: Warning C26833