[Patch v3 1/7] MdePkg/Include: Update Base.h to improve C++ compatibility

["Michael D Kinney" <michael.d.kinney@intel.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4134

* Map NULL to nullptr or __null when c++ compiler is used.
* Map STATIC_ASSERT to static_assert when a c++ compiler is used.
* Typecast RETURN_SUCCESS to type RETURN_STATUS to match type used
  by all return error/warning status codes.  C++ has stricter type
  checking and found this inconsistency.

Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
---
 MdePkg/Include/Base.h | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/MdePkg/Include/Base.h b/MdePkg/Include/Base.h
index d19ddfe4bba7..d209e6de280a 100644
--- a/MdePkg/Include/Base.h
+++ b/MdePkg/Include/Base.h
@@ -309,7 +309,15 @@ struct _LIST_ENTRY {
 ///
 /// NULL pointer (VOID *)
 ///
+#if defined (__cplusplus)
+  #if defined (_MSC_EXTENSIONS)
+#define NULL  nullptr
+  #else
+#define NULL  __null
+  #endif
+#else
 #define NULL  ((VOID *) 0)
+#endif
 
 //
 // Null character
@@ -760,7 +768,7 @@ typedef UINTN *BASE_LIST;
 **/
 #ifdef MDE_CPU_EBC
 #define STATIC_ASSERT(Expression, Message)
-#elif defined (_MSC_EXTENSIONS)
+#elif defined (_MSC_EXTENSIONS) || defined (__cplusplus)
 #define STATIC_ASSERT  static_assert
 #else
 #define STATIC_ASSERT  _Static_assert
@@ -959,7 +967,7 @@ typedef UINTN RETURN_STATUS;
 ///
 /// The operation completed successfully.
 ///
-#define RETURN_SUCCESS  0
+#define RETURN_SUCCESS  (RETURN_STATUS)(0)
 
 ///
 /// The image failed to load.
-- 
2.37.1.windows.1