Merge pull request #4806 from Rageking8/improve-__declspec-noreturn-example

Improve `__declspec(noreturn)` example

Author: Jak-MS

docs/cpp/noreturn.md

@@ -10,34 +10,49 @@ ms.assetid: 9c6517e5-22d7-4051-9974-3d2200ae4d1d
 
 **Microsoft Specific**
 
-This **`__declspec`** attribute tells the compiler that a function does not return. As a consequence, the compiler knows that the code following a call to a **`__declspec(noreturn)`** function is unreachable.
+The **`__declspec`** attribute tells the compiler that a function does not return. The compiler then knows that the code following a call to a **`__declspec(noreturn)`** function is unreachable.
 
-If the compiler finds a function with a control path that does not return a value, it generates a warning (C4715) or error message (C2202). If the control path cannot be reached due to a function that never returns, you can use **`__declspec(noreturn)`** to prevent this warning or error.
+If the compiler finds a function with a control path that does not return a value, it generates a warning (C4715) or error message (C2202). If the control path cannot be reached due to a function that never returns, use **`__declspec(noreturn)`** to prevent this warning or error.
 
 > [!NOTE]
 > Adding **`__declspec(noreturn)`** to a function that is expected to return can result in undefined behavior.
 
 ## Example
 
-In the following sample,the **`else`** clause does not contain a return statement.  Declaring `fatal` as **`__declspec(noreturn)`** avoids an error or warning message.
+In the following example, when the argument for `isZeroOrPositive` is negative, `fatal` is called. There isn't a return statement in that control path, which results in warning C4715 that not all control paths return a value. Declaring `fatal` as **`__declspec(noreturn)`** mitigates that warning, which is desirable because there is no point in it since `fatal()` terminates the program.
 
 ```cpp
 // noreturn2.cpp
-__declspec(noreturn) extern void fatal () {}
-
-int main() {
-   if(1)
-     return 1;
-   else if(0)
-     return 0;
-   else
-     fatal();
+#include <exception>
+
+__declspec(noreturn) void fatal()
+{
+   std::terminate();
+}
+
+int isZeroOrPositive(int val)
+{
+   if (val == 0)
+   {
+      return 0;
+   }
+   else if (val > 0)
+   {
+      return 1;
+   }
+   // this function terminates if val is negative
+   fatal();
+}
+
+int main()
+{
+   isZeroOrPositive(123);
 }
 ```
 
 **END Microsoft Specific**
 
 ## See also
 
-[__declspec](../cpp/declspec.md)<br/>
+[__declspec](../cpp/declspec.md)\
 [Keywords](../cpp/keywords-cpp.md)