diff --git a/io.c b/io.c
index 6038609..ad91df7 100644
--- a/io.c
+++ b/io.c
@@ -161,6 +161,12 @@ static ID id_write, id_read, id_getc, id_flush, id_readpartial, id_set_encoding;
 static VALUE sym_mode, sym_perm, sym_extenc, sym_intenc, sym_encoding, sym_open_args;
 static VALUE sym_textmode, sym_binmode, sym_autoclose;
 static VALUE sym_SET, sym_CUR, sym_END;
+#ifdef SEEK_DATA
+static VALUE sym_DATA;
+#endif
+#ifdef SEEK_HOLE
+static VALUE sym_HOLE;
+#endif
 
 struct argf {
     VALUE filename, current_file;
@@ -1551,6 +1557,14 @@ interpret_seek_whence(VALUE vwhence)
         return SEEK_CUR;
     if (vwhence == sym_END)
         return SEEK_END;
+#ifdef SEEK_DATA
+    if (vwhence == sym_DATA)
+        return SEEK_DATA;
+#endif
+#ifdef SEEK_HOLE
+    if (vwhence == sym_HOLE)
+        return SEEK_HOLE;
+#endif
     return NUM2INT(vwhence);
 }
 
@@ -11820,6 +11834,14 @@ Init_IO(void)
     rb_define_const(rb_cIO, "SEEK_CUR", INT2FIX(SEEK_CUR));
     /* Set I/O position from the end */
     rb_define_const(rb_cIO, "SEEK_END", INT2FIX(SEEK_END));
+#ifdef SEEK_DATA
+    /* Set I/O position to the next location containing data */
+    rb_define_const(rb_cIO, "SEEK_DATA", INT2FIX(SEEK_DATA));
+#endif
+#ifdef SEEK_HOLE
+    /* Set I/O position to the next hole */
+    rb_define_const(rb_cIO, "SEEK_HOLE", INT2FIX(SEEK_HOLE));
+#endif
     rb_define_method(rb_cIO, "rewind", rb_io_rewind, 0);
     rb_define_method(rb_cIO, "pos", rb_io_tell, 0);
     rb_define_method(rb_cIO, "pos=", rb_io_set_pos, 1);
@@ -11989,4 +12011,10 @@ Init_IO(void)
     sym_SET = ID2SYM(rb_intern("SET"));
     sym_CUR = ID2SYM(rb_intern("CUR"));
     sym_END = ID2SYM(rb_intern("END"));
+#ifdef SEEK_DATA
+    sym_DATA = ID2SYM(rb_intern("DATA"));
+#endif
+#ifdef SEEK_HOLE
+    sym_HOLE = ID2SYM(rb_intern("HOLE"));
+#endif
 }
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 999be76..469498c 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1565,6 +1565,22 @@ class TestIO < Test::Unit::TestCase
         f.seek(2, IO::SEEK_CUR)
         assert_equal("r\nbaz\n", f.read)
       }
+
+      if defined?(IO::SEEK_DATA)
+        open(t.path) { |f|
+          assert_equal("foo\n", f.gets)
+          f.seek(0, IO::SEEK_DATA)
+          assert_equal("foo\nbar\nbaz\n", f.read)
+        }
+      end
+
+      if defined?(IO::SEEK_HOLE)
+        open(t.path) { |f|2
+          assert_equal("foo\n", f.gets)
+          f.seek(0, IO::SEEK_HOLE)
+          assert_equal("", f.read)
+        }
+      end
     }
   end
 
@@ -1585,6 +1601,22 @@ class TestIO < Test::Unit::TestCase
         f.seek(2, :CUR)
         assert_equal("r\nbaz\n", f.read)
       }
+
+      if defined?(IO::SEEK_DATA)
+        open(t.path) { |f|
+          assert_equal("foo\n", f.gets)
+          f.seek(0, :DATA)
+          assert_equal("foo\nbar\nbaz\n", f.read)
+        }
+      end
+
+      if defined?(IO::SEEK_HOLE)
+        open(t.path) { |f|
+          assert_equal("foo\n", f.gets)
+          f.seek(0, :HOLE)
+          assert_equal("", f.read)
+        }
+      end
     }
   end