diff --git a/src/intrf.c b/src/intrf.c
index f0c70e5e..19747913 100644
--- a/src/intrf.c
+++ b/src/intrf.c
@@ -86,6 +86,7 @@ extern const char *monstr[];
 static char intr_buffer_screen[MAX_LINES][LINE_LENGTH+1];
 static int intr_nbr_line=0;
 static void set_parent_directory(char *dst_directory);
+static int vaff_txt(int line, WINDOW *window, const char *_format, va_list ap) __attribute__((format(printf, 3, 0)));
 struct file_info {
   struct td_list_head list;
   char name[4096];
@@ -1770,7 +1771,7 @@ char *ask_location(const char*msg, const char *src_dir)
   return res;
 }
 
-int vaff_txt(int line, WINDOW *window, const char *_format, va_list ap)
+static int vaff_txt(int line, WINDOW *window, const char *_format, va_list ap)
 {
   char buffer[1024];
   int i;
diff --git a/src/intrfn.h b/src/intrfn.h
index b777f991..d8a2ea67 100644
--- a/src/intrfn.h
+++ b/src/intrfn.h
@@ -40,7 +40,6 @@ void dump2(WINDOW *window, const void *dump_1, const void *dump_2, const unsigne
 void dump(WINDOW *window,const void *nom_dump,unsigned int lng);
 int screen_buffer_display_ext(WINDOW *window, const char *options_org, const struct MenuItem *menuItems, unsigned int *menu);
 int screen_buffer_display(WINDOW *window, const char *options_org, const struct MenuItem *menuItems);
-int vaff_txt(int line, WINDOW *window, const char *_format, va_list ap);
 int wgetch_nodelay(WINDOW *window);
 int wmenuSelect_ext(WINDOW *window, int y, int x, const struct MenuItem *menuItems, const unsigned int itemLength, const char *available, int menuType, unsigned int *current, int *real_key);
 int wmenuSelect(WINDOW *window, int y, int x, const struct MenuItem *menuItems, const unsigned int itemLength, const char *available, int menuType, unsigned int menuDefault);