diff --git a/include/json/value.h b/include/json/value.h
index b7ac2ad..b274688 100644
--- a/include/json/value.h
+++ b/include/json/value.h
@@ -505,10 +505,10 @@
 #endif
   } value_;
   ValueType type_ : 8;
-  int allocated_ : 1; // Notes: if declared as bool, bitfield is useless.
+  unsigned int allocated_ : 1; // Notes: if declared as bool, bitfield is useless.
 #ifdef JSON_VALUE_USE_INTERNAL_MAP
   unsigned int itemIsUsed_ : 1; // used by the ValueInternalMap container.
-  int memberNameIsStatic_ : 1;  // used by the ValueInternalMap container.
+  unsigned int memberNameIsStatic_ : 1;  // used by the ValueInternalMap container.
 #endif
   CommentInfo* comments_;