diff --git a/resource/csdk/connectivity/src/adapter_util/ca_adapter_net_ssl.c b/resource/csdk/connectivity/src/adapter_util/ca_adapter_net_ssl.c
index a05f0b4a42e5c564367c474a5c79e9783c16c3cf..a57f66a23135416f21e785b7d6aa48de7ae85ba4 100644
--- a/resource/csdk/connectivity/src/adapter_util/ca_adapter_net_ssl.c
+++ b/resource/csdk/connectivity/src/adapter_util/ca_adapter_net_ssl.c
@@ -21,7 +21,9 @@
 
 #include "iotivity_config.h"
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 
 #include <stddef.h>
 #include <stdbool.h>
diff --git a/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrclient.c b/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrclient.c
index 54e0df95355335e8a81aeacdf6c068237af6f498..1124b93da4af00ebc0072f76a9006fe69e587101 100644
--- a/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrclient.c
+++ b/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrclient.c
@@ -160,6 +160,7 @@ void CAEDRSocketConnectionStateCallback(int result, bt_socket_connection_state_e
                                        bt_socket_connection_s *connection, void *userData)
 {
     OIC_LOG(DEBUG, EDR_ADAPTER_TAG, "IN");
+    OC_UNUSED(userData);
 
     EDRDevice *device = NULL;
 
@@ -250,6 +251,7 @@ void CAEDRDeviceDiscoveryCallback(int result, bt_adapter_device_discovery_state_
                                  bt_adapter_device_discovery_info_s *discoveryInfo, void *userData)
 {
     OIC_LOG(DEBUG, EDR_ADAPTER_TAG, "IN");
+    OC_UNUSED(userData);
 
     EDRDevice *device = NULL;
 
@@ -372,6 +374,8 @@ void CAEDRServiceSearchedCallback(int32_t result,
                 bt_device_sdp_info_s *sdpInfo,void *userData)
 {
     OIC_LOG(DEBUG, EDR_ADAPTER_TAG, "IN");
+    OC_UNUSED(result);
+    OC_UNUSED(userData);
 
     if (NULL == sdpInfo)
     {
@@ -935,6 +939,7 @@ CAResult_t CAEDRClientDisconnect(const int32_t clientID)
 void CAEDRDataRecvCallback(bt_socket_received_data_s *data, void *userData)
 {
     OIC_LOG(DEBUG, EDR_ADAPTER_TAG, "IN");
+    OC_UNUSED(userData);
 
     EDRDevice *device = NULL;
 
diff --git a/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrnwmonitor.c b/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrnwmonitor.c
index c229b6815520c774a09f681eec9410ad05e1db36..a46a5c1ea340e2a05250abb15cc4d2b41a44d1a7 100644
--- a/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrnwmonitor.c
+++ b/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrnwmonitor.c
@@ -178,6 +178,8 @@ void CAEDRAdapterStateChangeCallback(int result, bt_adapter_state_e adapterState
                                      void *userData)
 {
     OIC_LOG(DEBUG, EDR_ADAPTER_TAG, "IN");
+    OC_UNUSED(result);
+    OC_UNUSED(userData);
 
     if (BT_ADAPTER_ENABLED == adapterState)
     {
diff --git a/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrserver.c b/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrserver.c
index f527f1dc6a7d51763e7d0981266e1fe2e3db8947..3e13678945e2c70ac5c4c5a667aa746bdf0fd3e1 100644
--- a/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrserver.c
+++ b/resource/csdk/connectivity/src/bt_edr_adapter/tizen/caedrserver.c
@@ -115,6 +115,7 @@ CAResult_t CAEDRServerStop()
 CAResult_t CAEDRServerInitialize(ca_thread_pool_t handle)
 {
     OIC_LOG(DEBUG, EDR_ADAPTER_TAG, "CAEDRServerInitialize");
+    OC_UNUSED(handle);
     return CA_STATUS_OK;
 }
 
diff --git a/resource/csdk/connectivity/src/ip_adapter/android/caipnwmonitor.c b/resource/csdk/connectivity/src/ip_adapter/android/caipnwmonitor.c
index 030fd3105765340c5179ab9c6d7e9c8b516e3444..7ee669676f51c41570abc94a1d63755355cdf739 100644
--- a/resource/csdk/connectivity/src/ip_adapter/android/caipnwmonitor.c
+++ b/resource/csdk/connectivity/src/ip_adapter/android/caipnwmonitor.c
@@ -195,7 +195,11 @@ u_arraylist_t *CAFindInterfaceChange()
                           .msg_iov = &iov,
                           .msg_iovlen = 1 };
 
+    // We do nothing with netlink event here.
+    // Android BroadcastReceiver will work instead.
     ssize_t len = recvmsg(caglobals.ip.netlinkFd, &msg, 0);
+    OC_UNUSED(len);
+
     return NULL;
 }
 
diff --git a/resource/csdk/connectivity/src/ip_adapter/tizen/caipnwmonitor.c b/resource/csdk/connectivity/src/ip_adapter/tizen/caipnwmonitor.c
index 60bdc4c7fe76d04e8646800166a92d6a16b085ec..332b626399889ffadc2a003d6648ec82c11baa26 100644
--- a/resource/csdk/connectivity/src/ip_adapter/tizen/caipnwmonitor.c
+++ b/resource/csdk/connectivity/src/ip_adapter/tizen/caipnwmonitor.c
@@ -393,6 +393,8 @@ static CAInterface_t *CANewInterfaceItem(int index, char *name, int family,
 
 void CAIPConnectionStateChangedCb(connection_type_e type, void* userData)
 {
+    OC_UNUSED(userData);
+
     switch (type)
     {
         case CONNECTION_TYPE_DISCONNECTED:
diff --git a/resource/csdk/connectivity/src/tcp_adapter/catcpserver.c b/resource/csdk/connectivity/src/tcp_adapter/catcpserver.c
index 5de71a8e672e0a0c43c15de7d68cc8a5e5c48f9d..540d275b5425893dec8a9d1c863d286960cf0873 100644
--- a/resource/csdk/connectivity/src/tcp_adapter/catcpserver.c
+++ b/resource/csdk/connectivity/src/tcp_adapter/catcpserver.c
@@ -609,34 +609,6 @@ static void CAAcceptConnection(CATransportFlags_t flag, CASocket_t *sock)
     }
 }
 
-#ifdef __WITH_TLS__
-static bool CAIsTlsMessage(const unsigned char* data, size_t length)
-{
-    if (NULL == data || 0 == length)
-    {
-        OIC_LOG_V(ERROR, TAG, "%s: null input param", __func__);
-        return false;
-    }
-
-    unsigned char first_byte = data[0];
-
-    //TLS Plaintext has four types: change_cipher_spec = [14], alert = [15],
-    //handshake = [16], application_data = [17] in HEX
-    const uint8_t tls_head_type[] = {0x14, 0x15, 0x16, 0x17};
-    size_t i = 0;
-
-    for (i = 0; i < sizeof(tls_head_type); i++)
-    {
-        if(tls_head_type[i] == first_byte)
-        {
-            return true;
-        }
-    }
-
-    return false;
-}
-#endif
-
 /**
  * Clean socket state data
  *
diff --git a/resource/csdk/connectivity/util/src/camanager/bt_le_manager/android/caleconnectionmanager.c b/resource/csdk/connectivity/util/src/camanager/bt_le_manager/android/caleconnectionmanager.c
index f9631d9ff8f841fdf4a90fd4a56801a49493d7e1..0f0c14f85712fd5790d5102468b9985a65070592 100644
--- a/resource/csdk/connectivity/util/src/camanager/bt_le_manager/android/caleconnectionmanager.c
+++ b/resource/csdk/connectivity/util/src/camanager/bt_le_manager/android/caleconnectionmanager.c
@@ -28,6 +28,7 @@
 #include "cacommonutil.h"
 #include "camanagerdevice.h"
 #include "caleclient.h"
+#include "caleserver.h"
 #include "caleutils.h"
 
 #define TAG "OIC_CA_MANAGER_LE"
diff --git a/resource/csdk/stack/src/occonnectionmanager.c b/resource/csdk/stack/src/occonnectionmanager.c
index 57b7a9c4ee9c92d8c0bcae59782cb4da42346421..d8a96528ccb99bca2bfd1747e1b45c82013d5ac0 100755
--- a/resource/csdk/stack/src/occonnectionmanager.c
+++ b/resource/csdk/stack/src/occonnectionmanager.c
@@ -248,6 +248,7 @@ static void OCAdapterStateChangedHandler(CATransportAdapter_t adapter, bool enab
 static void OCConnectionStateChangedHandler(const CAEndpoint_t *info, bool isConnected)
 {
     OIC_LOG(DEBUG, TAG, "OCConnectionStateChangedHandler");
+    OC_UNUSED(info);
 
     CAConnectUserPref_t connPrefer = CA_USER_PREF_CLOUD;
     CAResult_t ret = CAUtilCMGetConnectionUserConfig(&connPrefer);