diff --git a/bacnet-stack/include/datalink.h b/bacnet-stack/include/datalink.h
index 892999a1..5c0e2cd0 100644
--- a/bacnet-stack/include/datalink.h
+++ b/bacnet-stack/include/datalink.h
@@ -88,6 +88,10 @@
 #define MAX_HEADER (8)
 #define MAX_MPDU (MAX_HEADER+MAX_PDU)
 
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
 int datalink_send_pdu(
     BACNET_ADDRESS * dest,
     BACNET_NPDU_DATA * npdu_data,
@@ -108,6 +112,10 @@ extern void datalink_set_interface(
     char *ifname);
 extern void datalink_set(
     char *datalink_string);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
 #endif
 
 #endif
diff --git a/bacnet-stack/include/keylist.h b/bacnet-stack/include/keylist.h
index 951a3ddb..c21a5ba6 100644
--- a/bacnet-stack/include/keylist.h
+++ b/bacnet-stack/include/keylist.h
@@ -53,6 +53,10 @@ typedef struct Keylist {
 } KEYLIST_TYPE;
 typedef KEYLIST_TYPE *OS_Keylist;
 
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
 /* returns head of the list or NULL on failure. */
 OS_Keylist Keylist_Create(
     void);
@@ -109,4 +113,8 @@ KEY Keylist_Next_Empty_Key(
 int Keylist_Count(
     OS_Keylist list);
 
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
 #endif
diff --git a/bacnet-stack/include/objects.h b/bacnet-stack/include/objects.h
index 7a47a083..622bf01d 100644
--- a/bacnet-stack/include/objects.h
+++ b/bacnet-stack/include/objects.h
@@ -84,9 +84,4 @@ typedef struct object_device_t {
     uint32_t Database_Revision;
 } OBJECT_DEVICE_T;
 
-
-
-#ifdef __cplusplus
-}
-#endif /* __cplusplus */
 #endif