1 files changed, 1 insertions, 1 deletions
diff --git a/error.c b/error.c
index 0b63aa0512..7dacac8ce5 100644
--- a/error.c
+++ b/error.c
@@ -907,7 +907,7 @@ syserr_initialize(argc, argv, self)
     else err = "unknown error";
     if (!NIL_P(mesg)) {
 	VALUE str = mesg;
-	size_t len = strlen(err)+RSTRING(str)->len+3;
+	size_t len = strlen(err)+RSTRING(str)->len+4;
 	StringValue(str);
 	mesg = rb_str_new(0, len);
 	snprintf(RSTRING(mesg)->ptr, len, "%s - %.*s", err,