1 files changed, 15 insertions, 2 deletions
diff --git a/io.rb b/io.rb
index 1b6dddf9e5..549c5e62bd 100644
--- a/io.rb
+++ b/io.rb
@@ -60,7 +60,7 @@ class IO
   # return the symbol +:wait_readable+ instead. At EOF, it will return nil
   # instead of raising EOFError.
   def read_nonblock(len, buf = nil, exception: true)
-    __builtin_io_read_nonblock(len, buf, exception)
+    Primitive.io_read_nonblock(len, buf, exception)
   end
 
   # call-seq:
@@ -118,6 +118,19 @@ class IO
   # that write_nonblock should not raise an IO::WaitWritable exception, but
   # return the symbol +:wait_writable+ instead.
   def write_nonblock(buf, exception: true)
-    __builtin_io_write_nonblock(buf, exception)
+    Primitive.io_write_nonblock(buf, exception)
+  end
+
+  # call-seq:
+  #   readline(sep = $/, chomp: false)   -> string
+  #   readline(limit, chomp: false)      -> string
+  #   readline(sep, limit, chomp: false) -> string
+  #
+  # Reads a line as with IO#gets, but raises EOFError if already at end-of-stream.
+  #
+  # Optional keyword argument +chomp+ specifies whether line separators
+  # are to be omitted.
+  def readline(sep = $/, limit = nil, chomp: false)
+    Primitive.io_readline(sep, limit, chomp)
   end
 end