diff --git a/src/libCom/misc/ipAddrToAsciiAsynchronous.cpp b/src/libCom/misc/ipAddrToAsciiAsynchronous.cpp
index 0b9cf7445..bc04ea573 100644
--- a/src/libCom/misc/ipAddrToAsciiAsynchronous.cpp
+++ b/src/libCom/misc/ipAddrToAsciiAsynchronous.cpp
@@ -78,6 +78,9 @@ template class tsFreeList
 #   pragma warning ( pop )
 #endif
 
+static void ipAddrToAsciiEngineGlobalMutexConstruct ( void * );
+static void ipAddrToAsciiEngineGlobalMutexDestruct ( void * );
+
 // - this class executes the synchronous DNS query
 // - it creates one thread
 class ipAddrToAsciiEnginePrivate :