[PATCH 3/3 roland/nptl] NPTL: Add stub createthread.c

[Roland McGrath <roland at hack dot frob dot com>]

This adds a proper stub file for thread creation, documenting what sysdeps
implementations should do.  I'll commit this when I commit 1/3.


Thanks,
Roland


	* nptl/createthread.c: New file.

--- /dev/null
+++ b/nptl/createthread.c
@@ -0,0 +1,47 @@
+/* Low-level thread creation for NPTL.  Stub version.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+/* See the comments in pthread_create.c for the requirements for these
+   two macros and the create_thread function.  */
+
+#define START_THREAD_DEFN \
+  static void __attribute__ ((noreturn)) start_thread (void)
+#define START_THREAD_SELF THREAD_SELF
+
+static int
+create_thread (struct pthread *pd, const struct pthread_attr *attr,
+	       bool stopped_start, STACK_VARIABLES_PARMS, bool *thread_ran)
+{
+  /* If the implementation needs to do some tweaks to the thread after
+     it has been created at the OS level, it can set STOPPED_START here.  */
+
+  pd->stopped_start = stopped_start;
+  if (__glibc_unlikely (stopped_start))
+    /* We make sure the thread does not run far by forcing it to get a
+       lock.  We lock it here too so that the new thread cannot continue
+       until we tell it to.  */
+    lll_lock (pd->lock, LLL_PRIVATE);
+
+  return ENOSYS;
+
+  /* It's started now, so if we fail below, we'll have to cancel it
+     and let it clean itself up.  */
+  *thread_ran = true;
+
+  return 0;
+}