diff --git a/devsetup.h b/devsetup.h
index 7cddb8818..ee5494da0 100644
--- a/devsetup.h
+++ b/devsetup.h
@@ -101,6 +101,7 @@ private:
 
 extern int ptt(int nport, int ntx, int* iptt, int* nopen);
 
+#ifdef WIN32
 extern "C" {
   const bool HRDInterfaceConnect(const wchar_t *host, const ushort);
   void HRDInterfaceDisconnect();
@@ -108,5 +109,6 @@ extern "C" {
   const wchar_t* HRDInterfaceSendMessage(const wchar_t *msg);
   void HRDInterfaceFreeString(const wchar_t *lstring);
 }
+#endif
 
 #endif // DEVSETUP_H
diff --git a/mainwindow.cpp b/mainwindow.cpp
index b70c81d70..93eff7948 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -1,4 +1,4 @@
-//---------------------------------------------------------------- MainWindow
+//--------------------------------------------------------------- MainWindow
 #include "mainwindow.h"
 #include "ui_mainwindow.h"
 #include "devsetup.h"
diff --git a/rigclass.h b/rigclass.h
index e4c5cd6f5..b882bcf29 100644
--- a/rigclass.h
+++ b/rigclass.h
@@ -79,6 +79,7 @@ public:
   }
 };
 
+#ifdef WIN32
 extern "C" {
   const bool HRDInterfaceConnect(const wchar_t *host, const ushort);
   void HRDInterfaceDisconnect();
@@ -86,5 +87,6 @@ extern "C" {
   const wchar_t* HRDInterfaceSendMessage(const wchar_t *msg);
   void HRDInterfaceFreeString(const wchar_t *lstring);
 }
+#endif
 
 #endif	// _RIGCLASS_H