diff --git a/src/common/inc/sntp_client.h b/src/common/inc/sntp_client.h
index 4841bb0c..447af3ac 100644
--- a/src/common/inc/sntp_client.h
+++ b/src/common/inc/sntp_client.h
@@ -25,6 +25,10 @@
 #include "libiec61850_common_api.h"
 #include "hal_socket.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct sSNTPClient* SNTPClient;
 
 typedef void (*SNTPClient_UserCallback)(void* parameter, bool isSynced);
@@ -62,4 +66,8 @@ SNTPClient_stop(SNTPClient self);
 LIB61850_API void
 SNTPClient_destroy(SNTPClient self);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* LIBIEC61850_SRC_COMMON_INC_SNTP_CLIENT_H_ */
diff --git a/src/sntp/sntp_client.c b/src/sntp/sntp_client.c
index 9c6c76ee..27e9d09c 100644
--- a/src/sntp/sntp_client.c
+++ b/src/sntp/sntp_client.c
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2013-2020 Michael Zillgith
+ *  Copyright 2013-2022 Michael Zillgith
  *
  *  This file is part of libIEC61850.
  *
@@ -94,7 +94,7 @@ ntpTimeToNsTime(uint32_t coarse, uint32_t fine)
 static void
 nsTimeToNtpTime(nsSinceEpoch nsTime, uint32_t* coarse, uint32_t* fine)
 {
-    uint32_t secondsPart = (nsTime / 1000000000UL) + UNIX_EPOCH_OFFSET;
+    uint32_t secondsPart = (uint32_t)((nsTime / 1000000000UL) + UNIX_EPOCH_OFFSET);
 
     *coarse = secondsPart;
 
@@ -108,7 +108,7 @@ nsTimeToNtpTime(nsSinceEpoch nsTime, uint32_t* coarse, uint32_t* fine)
 static uint32_t
 nsTimeToSeconds(nsSinceEpoch nsTime)
 {
-    uint32_t secondsSinceEpoch = nsTime / 1000000000UL;
+    uint32_t secondsSinceEpoch = (uint32_t)(nsTime / 1000000000UL);
 
     return secondsSinceEpoch;
 }
@@ -118,7 +118,7 @@ getUsPartFromNsTime(nsSinceEpoch nsTime)
 {
     uint64_t nsPart = nsTime % 1000000000UL;
 
-    uint32_t msPart = nsPart / 1000UL;
+    uint32_t msPart = (uint32_t)(nsPart / 1000UL);
 
     return msPart;
 }