* ext/stringio/stringio.c: [DOC] add docs and example by @schneems [ci skip] [fix GH-527]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44859 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/stringio/stringio.c

@@ -1493,6 +1493,16 @@ strio_set_encoding(int argc, VALUE *argv, VALUE self)
 
 /*
  * Pseudo I/O on String object.
+ *
+ * Commonly used to simulate `$stdio` or `$stderr`
+ *
+ * === Examples
+ *
+ *   require 'stringio'
+ *
+ *   io = StringIO.new
+ *   io.puts "Hello World"
+ *   io.string #=> "Hello World"
  */
 void
 Init_stringio()