WARN_UNUSED_RESULT for windows

src/blockstore/implementations/integrity/KnownBlockVersions.h

@@ -21,7 +21,7 @@ namespace blockstore {
             KnownBlockVersions(KnownBlockVersions &&rhs); // NOLINT (intentionally not noexcept)
             ~KnownBlockVersions();
 
-            __attribute__((warn_unused_result))
+			WARN_UNUSED_RESULT
             bool checkAndUpdateVersion(uint32_t clientId, const BlockId &blockId, uint64_t version);
 
             uint64_t incrementVersion(const BlockId &blockId);

src/blockstore/interface/BlockStore2.h

@@ -19,12 +19,12 @@ public:
     return BlockId::Random();
   }
 
-  __attribute__((warn_unused_result))
+  WARN_UNUSED_RESULT
   virtual bool tryCreate(const BlockId &blockId, const cpputils::Data &data) = 0;
-  __attribute__((warn_unused_result))
+  WARN_UNUSED_RESULT
   virtual bool remove(const BlockId &blockId) = 0;
 
-  __attribute__((warn_unused_result))
+  WARN_UNUSED_RESULT
   virtual boost::optional<cpputils::Data> load(const BlockId &blockId) const = 0;
 
   // Store the block with the given blockId. If it doesn't exist, it is created.

src/cpp-utils/macros.h

@@ -17,4 +17,13 @@
  */
 #define UNUSED(expr) (void)(expr)
 
+/**
+ * Warn if function result is unused
+ */
+#if !defined(_MSC_VER)
+#define WARN_UNUSED_RESULT __attribute__((warn_unused_result))
+#else
+#define WARN_UNUSED_RESULT _Check_return_
+#endif
+
 #endif