diff --git a/include/sane/sanei_debug.h b/include/sane/sanei_debug.h
index e469d36d1..7888a7c13 100644
--- a/include/sane/sanei_debug.h
+++ b/include/sane/sanei_debug.h
@@ -3,55 +3,91 @@
 
 #include <sane/sanei.h>
 
+/* this header file defines:
+ *
+ * DBG_INIT() 		 - should be called before any other debug function
+ * DBG(level, fmt, ...)	 - prints a message at debug level `level' or higher
+ * 			   using a printf-like function
+ * IF_DBG(x)             - expands to x if debug support is enabled at
+ * 			   compile-time, if NDEBUG is defined at compile-time
+ * 			   this macro expands to nothing
+ *
+ * ENTRY(name)		 - expands to sane_BACKEND_NAME_name
+ *
+ * before you include sanei_debug.h, you'll have to define
+ *
+ * BACKEND_NAME		 - the name of your backend without double-quotes
+ * STUBS                 - if this is defined, nothing will happen
+ * DEBUG_DECLARE_ONLY    - generate prototypes instead of functions
+ * DEBUG_NOT_STATIC	 - doesn't generate static functions
+ *
+ */
+
 #define ENTRY(name)     PASTE(PASTE(PASTE(sane_,BACKEND_NAME),_),name)
 
-/* The cpp that comes with GNU C 2.5 seems to have troubles understanding
-   vararg macros.  */
-#if __GNUC__ - 0 > 2 || (__GNUC__ - 0 == 2 && __GNUC_MINOR__ > 5)
-# define HAVE_VARARG_MACROS
-#endif
-
-extern void sanei_debug (int level, const char *msg, ...);
-
 #ifdef NDEBUG
-# define DBG_LEVEL  (0)
+  
+extern void sanei_debug_ndebug (int level, const char *msg, ...);
+	
+# define DBG_LEVEL	(0)
 # define DBG_INIT()
-# ifdef HAVE_VARARG_MACROS
-#  define DBG(level, msg, args...)
-# else
-#  define DBG           if (0) sanei_debug
-# endif
-#  define IF_DBG(x)
-#else
-# include <stdio.h>
+# define DBG		sanei_debug_ndebug
+# define IF_DBG(x)
+	
+#else /* !NDEBUG */
+	
+# define DBG_LEVEL      PASTE(sanei_debug_,BACKEND_NAME)
 
-#define DBG_LEVEL       PASTE(sanei_debug_,BACKEND_NAME)
-
-#if defined(BACKEND_NAME) && !defined(STUBS)
-int DBG_LEVEL;
-#endif
+# if defined(BACKEND_NAME) && !defined(STUBS)
+#  ifdef DEBUG_DECLARE_ONLY
+extern int DBG_LEVEL;
+#  else /* !DEBUG_DECLARE_ONLY */
+int DBG_LEVEL = 0;
+#  endif /* DEBUG_DECLARE_ONLY */
+# endif /* BACKEND_NAME && !STUBS */
 
 # define DBG_INIT()                                     \
   sanei_init_debug (STRINGIFY(BACKEND_NAME), &DBG_LEVEL)
 
-/* The cpp that comes with GNU C 2.5 seems to have troubles understanding
-   vararg macros.  */
-#ifdef HAVE_VARARG_MACROS
-extern void sanei_debug_max (int level, int max_level, const char *msg, ...);
+# define DBG_LOCAL	PASTE(DBG_LEVEL,_call)
 
-# define DBG(level, msg, args...)                                       \
-  do {                                                                  \
-      sanei_debug_max ( level, DBG_LEVEL,                               \
-                        "[" STRINGIFY(BACKEND_NAME) "] " msg, ##args);  \
-  } while (0)
 
-#else
-# define DBG            sanei_debug
-#endif /* HAVE_VARARG_MACROS */
+# ifndef STUBS
+
+#  ifdef DEBUG_DECLARE_ONLY
+
+extern void DBG_LOCAL (int level, const char *msg, ...);
+
+#  else /* !DEBUG_DECLARE_ONLY */
+
+#   include <stdarg.h>
+	
+extern void sanei_debug_msg 
+  (int level, int max_level, const char *be, const char *fmt, va_list ap);
+
+#   ifndef DEBUG_NOT_STATIC
+static
+#   endif /* !DEBUG_NOT_STATIC */
+void
+DBG_LOCAL (int level, const char *msg, ...)
+{
+  va_list ap;
+
+  va_start (ap, msg);
+  sanei_debug_msg (level, DBG_LEVEL, STRINGIFY(BACKEND_NAME), msg, ap);
+  va_end (ap);
+}
+
+#  endif /* DEBUG_NOT_STATIC */
+
+# endif /* !STUBS */
+
+# define DBG            DBG_LOCAL
 
 extern void sanei_init_debug (const char * backend, int * debug_level_var);
   
 # define IF_DBG(x)      x
+
 #endif /* NDEBUG */
 
 #endif /* _SANEI_DEBUG_H */