diff --git a/programs/fileio.c b/programs/fileio.c
index dafc12468..8d6ab35d0 100644
--- a/programs/fileio.c
+++ b/programs/fileio.c
@@ -145,8 +145,8 @@ static clock_t g_time = 0;
 **************************************/
 #include  <signal.h>
 
-const char* g_artefact = NULL;
-void INThandler(int sig)
+static const char* g_artefact = NULL;
+static void INThandler(int sig)
 {
     assert(sig==SIGINT); (void)sig;
 #if !defined(_MSC_VER)