diff --git a/src/libavrdude.h b/src/libavrdude.h
index 453b22a0..60cf4ebf 100644
--- a/src/libavrdude.h
+++ b/src/libavrdude.h
@@ -59,6 +59,7 @@ typedef uint32_t pinmask_t;
 #define LIBAVRDUDE_NOTSUPPORTED (-2) // operation not supported
 #define LIBAVRDUDE_SOFTFAIL (-3) // returned, eg, by avr_signature() if caller
                                  // might proceed with chip erase
+#define LIBAVRDUDE_EXIT (-4)     // End all operations in this session
 
 /* formerly lists.h */
 
diff --git a/src/stk500.c b/src/stk500.c
index d873c6d4..13170891 100644
--- a/src/stk500.c
+++ b/src/stk500.c
@@ -799,7 +799,7 @@ static int stk500_parseextparms(const PROGRAMMER *pgm, const LISTID extparms)
       }
       msg_error("  -xxtal=<arg>[M|k]     Set programmer xtal frequency\n");
       msg_error("  -xhelp                Show this help menu and exit\n");
-      exit(0);
+      return LIBAVRDUDE_EXIT;;
     }
 
      pmsg_error("invalid extended parameter %s\n", extended_param);