Tweaks.

Author: [email protected]

docs/build/reference/zc-conformance.md

@@ -1,7 +1,7 @@
 ---
 title: "/Zc (Conformance)"
 description: "The /Zc conformance compiler options enable or disable support for conforming or backward-compatible behavior."
-ms.date: 08/12/2021
+ms.date: 12/02/2021
 helpviewer_keywords: ["/Zc compiler options [C++]", "-Zc compiler options [C++]", "Conformance compiler options", "Zc compiler options [C++]"]
 ---
 # `/Zc` (Conformance)

docs/build/reference/zc-externc.md

@@ -19,7 +19,7 @@ The **`/Zc:externC`** compiler option tells the compiler to conform to the C++ s
 
 The **`/Zc:externC`** compiler option checks the definitions of functions declared by using `extern "C"`.
 
-The **`/Zc:externC`** option is available starting in Visual Studio 2019 version 16.3. It's off when the [`/permissive-`](permissive-standards-conformance.md) option isn't set. In earlier versions of Visual Studio, and by default or if **`/Zc:externC-`** is specified, Visual Studio is permissive about matching declarations of `extern "C"` functions. The **`/permissive-`** option enables **`/Zc:externC`**, so it's on by default in projects that use **`/std:c++20`** or **`/std:c++latest`**.
+The **`/Zc:externC`** option is available starting in Visual Studio 2019 version 16.3. It's off when the [`/permissive-`](permissive-standards-conformance.md) option isn't set. In earlier versions of Visual Studio, and by default or if **`/Zc:externC-`** is specified, Visual Studio is permissive about matching declarations of `extern "C"` functions. The **`/permissive-`** option enables **`/Zc:externC`**, so it's on by default in projects that use **`/std:c++20`** or **`/std:c++latest`**. The **`/Zc:externC`** option must come after a **`/permissive-`** option on the command line.
 
 Mismatched `extern "C"` declarations can cause compiler errors [C2116](../../error-messages/compiler-errors-1/compiler-error-c2116.md) and [C2733](../../error-messages/compiler-errors-1/compiler-error-c2733.md). In C++ code, an error can occur if you declare an `extern "C"` function more than once and use different parameter types, even if the types have the same definitions. The **`/Zc:externC-`** option relaxes this check, and doesn't produce these errors.