diff --git a/src/evalfunc.c b/src/evalfunc.c
index 8d6255d..1505418 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -2218,7 +2218,7 @@
     {"prompt_setprompt", 2, 2, FEARG_1,	    arg2_buffer_string,
 			ret_void,	    JOB_FUNC(f_prompt_setprompt)},
     {"prop_add",	3, 3, FEARG_1,	    arg3_number_number_dict,
-			ret_void,	    PROP_FUNC(f_prop_add)},
+			ret_number,	    PROP_FUNC(f_prop_add)},
     {"prop_add_list",	2, 2, FEARG_1,	    arg2_dict_any_list_any,
 			ret_void,	    PROP_FUNC(f_prop_add_list)},
     {"prop_clear",	1, 3, FEARG_1,	    arg3_number_number_dict,