diff --git a/ChangeLog b/ChangeLog
index 23712b0900..bcb131fa41 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Mar 15 17:28:30 2010  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* io.c (rb_io_print): RDoc update.  a patch from Daniel Kelley
+	  in [ruby-core:28643].
+
 Mon Mar 15 14:06:07 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* random.c (next_state): no initialization here.
diff --git a/io.c b/io.c
index 6fd9f54d10..60afd6c3c7 100644
--- a/io.c
+++ b/io.c
@@ -5884,7 +5884,9 @@ rb_f_printf(int argc, VALUE *argv)
  *     ios.print(obj, ...)     => nil
  *
  *  Writes the given object(s) to <em>ios</em>. The stream must be
- *  opened for writing. If the output record separator (<code>$\\</code>)
+ *  opened for writing. If the output field separator (<code>$,</code>)
+ *  is not <code>nil</code>, it will be inserted between each object.
+ *  If the output record separator (<code>$\\</code>)
  *  is not <code>nil</code>, it will be appended to the output. If no
  *  arguments are given, prints <code>$_</code>. Objects that aren't
  *  strings will be converted by calling their <code>to_s</code> method.
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index a8860e1654..2da2ae95e6 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1396,6 +1396,23 @@ End
     assert_in_out_err(["-", t.path], "print while $<.gets", %w(foo bar baz), [])
   end
 
+  def test_print_separators
+    $, = ':'
+    $\ = "\n"
+    r, w = IO.pipe
+    w.print('a')
+    w.print('a','b','c')
+    w.close
+    assert_equal("a\n", r.gets)
+    assert_equal("a:b:c\n", r.gets)
+    assert_nil r.gets
+    r.close
+    
+  ensure
+    $, = nil
+    $\ = nil
+  end
+
   def test_putc
     pipe(proc do |w|
       w.putc "A"