1 files changed, 68 insertions, 0 deletions
diff --git a/sysdeps/pthread/tst-_res1.c b/sysdeps/pthread/tst-_res1.c
new file mode 100644
index 0000000000..3e186bcb39
--- /dev/null
+++ b/sysdeps/pthread/tst-_res1.c
@@ -0,0 +1,68 @@
+/* Copyright (C) 2003-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+/* Test whether _res in glibc 2.1.x and earlier (before __res_state()
+   was introduced) works.  Portable programs should never do the
+   dirty things below.  */
+
+#include <pthread.h>
+#include <resolv.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+void *tf (void *resp)
+{
+  if (resp == &_res || resp == __res_state ())
+    abort ();
+  _res.retry = 24;
+  return NULL;
+}
+
+void do_test (struct __res_state *resp)
+{
+  if (resp != &_res || resp != __res_state ())
+    abort ();
+  if (_res.retry != 12)
+    abort ();
+}
+
+int main (void)
+{
+#undef _res
+  extern struct __res_state _res;
+  pthread_t th;
+
+  _res.retry = 12;
+  if (pthread_create (&th, NULL, tf, &_res) != 0)
+    {
+      puts ("create failed");
+      exit (1);
+    }
+
+  do_test (&_res);
+
+  if (pthread_join (th, NULL) != 0)
+    {
+      puts ("join failed");
+      exit (1);
+    }
+
+  do_test (&_res);
+
+  exit (0);
+}