diff --git a/ChangeLog b/ChangeLog
index acd8e51402..3be745a8bd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Aug 21 01:57:03 2008  Tanaka Akira  <akr@fsij.org>
+
+	* io.c (open_key_args): IO.foreach(path, rs, limit) didn't work.
+
 Thu Aug 21 01:31:34 2008  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (rb_file_sysopen_internal): unused function removed.
diff --git a/io.c b/io.c
index 880b3dc8a2..931692025d 100644
--- a/io.c
+++ b/io.c
@@ -6666,7 +6666,7 @@ open_key_args(int argc, VALUE *argv, struct foreach_arg *arg)
 
     FilePathValue(argv[0]);
     arg->io = 0;
-    arg->argc = argc > 1 ? 1 : 0;
+    arg->argc = argc - 1;
     arg->argv = argv + 1;
     if (argc == 1) {
       no_key:
@@ -6675,8 +6675,7 @@ open_key_args(int argc, VALUE *argv, struct foreach_arg *arg)
     }
     opt = rb_check_convert_type(argv[argc-1], T_HASH, "Hash", "to_hash");
     if (NIL_P(opt)) goto no_key;
-    if (argc > 2) arg->argc = 1;
-    else arg->argc = 0;
+    arg->argc--;
 
     v = rb_hash_aref(opt, sym_open_args);
     if (!NIL_P(v)) {
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index a181b41023..e487927ebe 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1083,6 +1083,10 @@ class TestIO < Test::Unit::TestCase
 
     t = make_tempfile
 
+    a = []
+    IO.foreach(t.path) {|x| a << x }
+    assert_equal(["foo\n", "bar\n", "baz\n"], a)
+
     a = []
     IO.foreach(t.path, {:mode => "r" }) {|x| a << x }
     assert_equal(["foo\n", "bar\n", "baz\n"], a)
@@ -1094,6 +1098,28 @@ class TestIO < Test::Unit::TestCase
     a = []
     IO.foreach(t.path, {:open_args => ["r"] }) {|x| a << x }
     assert_equal(["foo\n", "bar\n", "baz\n"], a)
+
+    a = []
+    IO.foreach(t.path, "b") {|x| a << x }
+    assert_equal(["foo\nb", "ar\nb", "az\n"], a)
+
+    a = []
+    IO.foreach(t.path, 3) {|x| a << x }
+    assert_equal(["foo", "\n", "bar", "\n", "baz", "\n"], a)
+
+    a = []
+    IO.foreach(t.path, "b", 3) {|x| a << x }
+    assert_equal(["foo", "\nb", "ar\n", "b", "az\n"], a)
+
+  end
+
+  def test_s_readlines
+    t = make_tempfile
+
+    assert_equal(["foo\n", "bar\n", "baz\n"], IO.readlines(t.path))
+    assert_equal(["foo\nb", "ar\nb", "az\n"], IO.readlines(t.path, "b"))
+    assert_equal(["fo", "o\n", "ba", "r\n", "ba", "z\n"], IO.readlines(t.path, 2))
+    assert_equal(["fo", "o\n", "b", "ar", "\nb", "az", "\n"], IO.readlines(t.path, "b", 2))
   end
 
   def test_printf
@@ -1219,6 +1245,8 @@ class TestIO < Test::Unit::TestCase
   def test_s_read
     t = make_tempfile
 
+    assert_equal("foo\nbar\nbaz\n", File.read(t.path))
+    assert_equal("foo\nba", File.read(t.path, 6))
     assert_equal("bar\n", File.read(t.path, 4, 4))
   end