Merge pull request #5534 from TylerMSFT/warn

fix language tagging and some of the code samples

Author: JamesJBarnett

docs/code-quality/c6031.md

@@ -1,10 +1,9 @@
 ---
 title: Warning C6031
 description: "Describes C++ Code Analysis warning C6031 and how to resolve it."
-ms.date: 10/04/2022
+ms.date: 4/5/2024
 f1_keywords: ["C6031", "RETVAL_IGNORED_FUNC_COULD_FAIL", "__WARNING_RETVAL_IGNORED_FUNC_COULD_FAIL"]
 helpviewer_keywords: ["C6031"]
-ms.assetid: 59e1ef0a-b3ca-4ffa-bcb3-ad2bd22ece22
 ---
 # Warning C6031
 
@@ -16,44 +15,48 @@ Warning C6031 indicates the caller doesn't check a function's return value for f
 
 In general, it isn't safe to assume that calls to functions requiring disk, network, memory, or other resources will succeed. The caller should always check the return value and handle error cases appropriately. Also consider using the `_Must_inspect_result_` annotation, which checks that the value is examined in a useful way.
 
+This warning applies to both C and C++ code.
+
 Code analysis name: `RETVAL_IGNORED_FUNC_COULD_FAIL`
 
 ## Example
 
 The following code generates warning C6031:
 
-```cpp
+```c
 #include <stdio.h>
-void f( )
+int main()
 {
-    fopen( "test.c", "r" ); // C4996, C6031 return value ignored
+    fopen("test.c", "r"); // C4996, C6031 return value ignored
     // code ...
 }
 ```
 
 To correct this warning, check the return value of the function as shown in the following code:
 
-```cpp
+```c
 #include <stdio.h>
-void f( )
+int main()
 {
-    FILE *stream;
-    if ( (stream = fopen( "test.c", "r" )) == NULL )
+    FILE* stream;
+    if ((stream = fopen("test.c", "r")) == NULL)
+    {
         return;
+    }
     // code ...
 }
 ```
 
 The following code uses safe function `fopen_s` to correct this warning:
 
-```cpp
+```c
 #include <stdio.h>
-void f( )
+int main()
 {
-    FILE *stream;
+    FILE* stream;
     errno_t err;
 
-    if ( (err = fopen_s( &stream, "test.c", "r" )) !=0 )
+    if ((err = fopen_s(&stream, "test.c", "r")) != 0)
     {
         // code ...
     }
@@ -64,23 +67,30 @@ This warning is also generated if the caller ignores the return value of a funct
 
 ```cpp
 #include <sal.h>
-_Check_return_ bool func();
+_Check_return_ bool func()
+{
+    return true;
+}
 
-void test_f()
+int main()
 {
-    func(); //  Warning C6031
+    func();
 }
 ```
 
 To correct the previous warning, check the return value as shown in the following code:
 
 ```cpp
 #include <sal.h>
-_Check_return_ bool func();
+_Check_return_ bool func()
+{
+    return true;
+}
 
-void test_f()
+int main()
 {
-    if ( func() ) {
+    if (func())
+    {
         // code ...
     }
 }
@@ -91,10 +101,12 @@ In cases where it's necessary to ignore the return value of a function, assign t
 ```cpp
 #include <tuple>
 #include <ctime>
+#include <cstdlib>
 #include <stdio.h>
-void f()
+
+int main()
 {
-    std::srand(static_cast(std::time(nullptr))); // set initial seed value to system clock
+    std::srand(static_cast<unsigned int>(std::time(nullptr))); // set initial seed value to system clock
     std::ignore = std::rand(); // Discard the first result as the few random results are always small.
     // ... 
 }