Merge pull request #5485 from MicrosoftDocs/main

3/7/2024 AM Publish

Author: PhilKang0704

docs/code-quality/c6328.md

@@ -1,41 +1,66 @@
 ---
 description: "Learn more about: Warning C6328"
 title: Warning C6328
-ms.date: 09/15/2022
+ms.date: 02/14/2024
 f1_keywords: ["C6328", "FORMAT_SIZE_MISMATCH", "__WARNING_FORMAT_SIZE_MISMATCH"]
 helpviewer_keywords: ["C6328"]
 ms.assetid: e25b00fa-d344-4dc9-b322-b4f1ae06f315
 ---
 # Warning C6328
 
-> Size mismatch: '*type*' passed as parameter '*number*' when '*type*' is required in call to '*function-name*'
+> Size mismatch: '*type*' passed as _Param_(*number*) when '*type*' is required in call to '*function-name*'
 
 ## Remarks
 
-An argument of type `char` passed to C runtime, character-based routines named `is<xxx>` (for example, `isspace`) can have unpredictable results. For example, an SBCS or MBCS single-byte character of type `char` with a value greater than `0x7F` is a negative value. If a `char` is passed, the compiler might convert the value to a signed `int` or a signed `long`. This value could be sign-extended by the compiler, with unexpected results. This issue could result in a function like `isspace`, which only expects values from 0-255 or `EOF`, being sent a negative value.
-
-Warning C6328 exists specifically to catch this bug. For characters in the 7-bit ASCII range, the cast is unnecessary. Characters outside that range can have unpredictable results such as program fault and termination.
+This warning indicates that type required by the format specifier and the type of the expression passed in don't match.
+Using the wrong format specifier is undefined behavior. To fix the warning, make sure that the format specifiers match the types of the expressions passed in.
 
 Code analysis name: `FORMAT_SIZE_MISMATCH`
 
 ## Example
 
-The following code generates this warning. By default, `char` is a signed type in the Microsoft C++ compiler, so the range of values of a `char` is -128 to 127. Therefore, in the following code, `c` would be sign-extended to a signed `int` with a value of -37, which is outside the valid range for [isspace](../standard-library/locale-functions.md#isspace):
+```cpp
+#include <cstdio>
+
+void f(long long a)
+{
+    printf("%d\n", a); // C6328 emitted.
+}
+```
+
+There are multiple ways to fix the undefined behavior. We can change the format specifier:
+
+```cpp
+#include <cstdio>
+
+void f(long long a)
+{
+    printf("%lld\n", a); // No C6328 emitted.
+}
+```
+
+We can change the type of the expression:
 
 ```cpp
-void f()
+#include <cstdio>
+
+void f(int a)
 {
-    char c = -37;
-    int retVal = isspace(c);
+    printf("%d\n", a); // No C6328 emitted.
 }
 ```
 
-The following code remediates this warning by using `static_cast`:
+As a last resort when overflow can't happen, we can introduce a cast:
 
 ```cpp
-void f( )
+#include <cstdio>
+
+void f(unsigned char a)
 {
-    char c = -37;
-    int retVal = isspace(static_cast<unsigned char>(c));
+    printf("%hhd\n", static_cast<signed char>(a)); // No C6328 emitted.
 }
 ```
+
+## See also
+
+[C6340](c6340.md)

docs/code-quality/c6340.md

@@ -1,11 +1,67 @@
 ---
 description: "Learn more about: Warning C6340"
 title: Warning C6340
-ms.date: 11/04/2016
-f1_keywords: ["C6340"]
+ms.date: 02/14/2024
+f1_keywords: ["C6340", "FORMAT_SIGN_MISMATCH"]
 helpviewer_keywords: ["C6340"]
 ms.assetid: c4fe474f-5a27-4148-ba35-1ef021371e13
 ---
 # Warning C6340
 
-> Mismatch on sign: Incorrect type passed as parameter in call to function
+> Mismatch on sign: '*type*' passed as _Param_(*number*) when some (signed|unsigned) type is required in call to '*function-name*'
+
+## Remarks
+
+This warning indicates that sign of the type required by the format specifier and sign of the type of the expression passed in don't match.
+Using the wrong format specifier is undefined behavior. To fix the warning, make sure that the format specifiers match the types of the expressions passed in.
+
+Code analysis name: `FORMAT_SIGN_MISMATCH`
+
+## Example
+
+```cpp
+#include <cstdio>
+
+void f(unsigned char a)
+{
+    printf("%hhd\n", a); // C6340 emitted.
+}
+```
+There are multiple ways to fix the undefined behavior. We can change the format specifier:
+
+```cpp
+#include <cstdio>
+
+void f(unsigned char a)
+{
+    printf("%hhu\n", a); // No C6340 emitted.
+}
+```
+
+We can change the type of the expression:
+
+```cpp
+#include <cstdio>
+
+void f(signed char a)
+{
+    printf("%hhd\n", a); // No C6340 emitted.
+}
+```
+
+As a last resort when overflow can't happen, we can introduce a cast:
+
+```cpp
+#include <cstdio>
+
+void f(long long a)
+{
+    printf("%d\n", static_cast<int>(a)); // No C6328 emitted.
+}
+```
+
+## See also
+
+[C6328](c6328.md)
+
+

docs/error-messages/compiler-warnings/compiler-warning-level-3-c4066.md

@@ -1,13 +1,29 @@
 ---
 description: "Learn more about: Compiler Warning (level 3) C4066"
 title: "Compiler Warning (level 3) C4066"
-ms.date: "11/04/2016"
+ms.date: "03/06/2024"
 f1_keywords: ["C4066"]
 helpviewer_keywords: ["C4066"]
-ms.assetid: f2ae6465-a140-459a-87fd-c8f25fafedd4
 ---
 # Compiler Warning (level 3) C4066
 
 characters beyond first in wide-character constant ignored
 
 The compiler processes only the first character of a wide-character constant.
+
+```cpp
+// C4066.cpp
+// compile with: /W3
+#include <iostream>
+
+int main()
+{
+    wchar_t wc = L'AB';   // C4066
+
+    std::wcout << wc;
+}
+```
+
+```output
+A
+```