diff --git a/src/db/dbChannelIO.cpp b/src/db/dbChannelIO.cpp
index 770fbbc14..e3b903e25 100644
--- a/src/db/dbChannelIO.cpp
+++ b/src/db/dbChannelIO.cpp
@@ -69,7 +69,7 @@ void dbChannelIO::destructor ( epicsGuard < epicsMutex > & guard )
 }
 
 void dbChannelIO::destroy ( 
-    epicsGuard < epicsMutex > & callbackControlGuard, 
+    epicsGuard < epicsMutex > &, 
     epicsGuard < epicsMutex > & mutualExclusionGuard )
 {
     mutualExclusionGuard.assertIdenticalMutex ( this->mutex );
@@ -133,7 +133,7 @@ void dbChannelIO::subscribe (
 }
 
 void dbChannelIO::ioCancel ( 
-    epicsGuard < epicsMutex > & callbackControlGuard, 
+    epicsGuard < epicsMutex > &, 
     epicsGuard < epicsMutex > & mutualExclusionGuard,
     const ioid & id )
 {
diff --git a/src/db/dbPutNotifyBlocker.cpp b/src/db/dbPutNotifyBlocker.cpp
index c6fe4101d..34be38de7 100644
--- a/src/db/dbPutNotifyBlocker.cpp
+++ b/src/db/dbPutNotifyBlocker.cpp
@@ -186,7 +186,7 @@ void dbPutNotifyBlocker::show ( unsigned level ) const
 }
 
 void dbPutNotifyBlocker::show ( 
-    epicsGuard < epicsMutex > & guard, unsigned level ) const
+    epicsGuard < epicsMutex > &, unsigned level ) const
 {
     printf ( "put notify blocker at %p\n", 
         static_cast <const void *> ( this ) );
diff --git a/src/iocsh/iocsh.cpp b/src/iocsh/iocsh.cpp
index 7a123870e..964807555 100644
--- a/src/iocsh/iocsh.cpp
+++ b/src/iocsh/iocsh.cpp
@@ -338,7 +338,8 @@ openRedirect(const char *filename, int lineno, struct iocshRedirect *redirect)
  * Start I/O redirection
  */
 static void
-startRedirect(const char *filename, int lineno, struct iocshRedirect *redirect)
+startRedirect(const char * /*filename*/, int /*lineno*/,
+              struct iocshRedirect *redirect)
 {
     int i;