diff --git a/src/ptrace/_UPT_resume.c b/src/ptrace/_UPT_resume.c
index e69de29b..11242e8d 100644
--- a/src/ptrace/_UPT_resume.c
+++ b/src/ptrace/_UPT_resume.c
@@ -0,0 +1,38 @@
+/* libunwind - a platform-independent unwind library
+   Copyright (C) 2003 Hewlett-Packard Co
+	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
+
+This file is part of libunwind.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
+
+#include "_UPT_internal.h"
+
+int
+_UPT_resume (unw_addr_space_t as, unw_cursor_t *c, void *arg)
+{
+  struct UPT_info *ui = arg;
+
+#ifdef HAVE_TTRACE
+# warning No support for ttrace() yet.
+#else
+  return ptrace (PTRACE_CONT, ui->pid, 0, 0);
+#endif
+}