diff --git a/sprintf.c b/sprintf.c
index 52a7168dc9..9a08764448 100644
--- a/sprintf.c
+++ b/sprintf.c
@@ -120,7 +120,7 @@ sign_bits(int base, const char *p)
 #define GETASTER(val) do { \
     t = p++; \
     n = 0; \
-    GETNUM(n, (val)); \
+    GETNUM(n, val); \
     if (*p == '$') { \
 	tmp = GETPOSARG(n); \
     } \
diff --git a/test/ruby/test_sprintf.rb b/test/ruby/test_sprintf.rb
index a57509f458..2a0fc487c1 100644
--- a/test/ruby/test_sprintf.rb
+++ b/test/ruby/test_sprintf.rb
@@ -309,6 +309,12 @@ class TestSprintf < Test::Unit::TestCase
 
   def test_star
     assert_equal("-1 ", sprintf("%*d", -3, -1))
+    assert_raise_with_message(ArgumentError, /width too big/) {
+      sprintf("%*999999999999999999999999999999999999999999999999999999999999$d", 1)
+    }
+    assert_raise_with_message(ArgumentError, /prec too big/) {
+      sprintf("%.*999999999999999999999999999999999999999999999999999999999999$d", 1)
+    }
   end
 
   def test_escape