From 2ab3d99967d68c79351fe2a3df22c445447e3010 Mon Sep 17 00:00:00 2001
From: Michał Cichoń <michcic@gmail.com>
Date: Tue, 15 Nov 2011 22:28:48 +0100
Subject: Initial import.

---
 pthreads/src/pthread_timechange_handler_np.c | 108 +++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 pthreads/src/pthread_timechange_handler_np.c

(limited to 'pthreads/src/pthread_timechange_handler_np.c')

diff --git a/pthreads/src/pthread_timechange_handler_np.c b/pthreads/src/pthread_timechange_handler_np.c
new file mode 100644
index 0000000..0f97e74
--- /dev/null
+++ b/pthreads/src/pthread_timechange_handler_np.c
@@ -0,0 +1,108 @@
+/*
+ * pthread_timechange_handler_np.c
+ *
+ * Description:
+ * This translation unit implements miscellaneous thread functions.
+ *
+ * --------------------------------------------------------------------------
+ *
+ *      Pthreads-win32 - POSIX Threads Library for Win32
+ *      Copyright(C) 1998 John E. Bossom
+ *      Copyright(C) 1999,2005 Pthreads-win32 contributors
+ * 
+ *      Contact Email: rpj@callisto.canberra.edu.au
+ * 
+ *      The current list of contributors is contained
+ *      in the file CONTRIBUTORS included with the source
+ *      code distribution. The list can also be seen at the
+ *      following World Wide Web location:
+ *      http://sources.redhat.com/pthreads-win32/contributors.html
+ * 
+ *      This 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 of the License, or (at your option) any later version.
+ * 
+ *      This 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 this library in the file COPYING.LIB;
+ *      if not, write to the Free Software Foundation, Inc.,
+ *      59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "pthread.h"
+#include "implement.h"
+
+/*
+ * Notes on handling system time adjustments (especially negative ones).
+ * ---------------------------------------------------------------------
+ *
+ * This solution was suggested by Alexander Terekhov, but any errors
+ * in the implementation are mine - [Ross Johnson]
+ *
+ * 1) The problem: threads doing a timedwait on a CV may expect to timeout
+ *    at a specific absolute time according to a system timer. If the
+ *    system clock is adjusted backwards then those threads sleep longer than
+ *    expected. Also, pthreads-win32 converts absolute times to intervals in
+ *    order to make use of the underlying Win32, and so waiting threads may
+ *    awake before their proper abstimes.
+ *
+ * 2) We aren't able to distinquish between threads on timed or untimed waits,
+ *    so we wake them all at the time of the adjustment so that they can
+ *    re-evaluate their conditions and re-compute their timeouts.
+ *
+ * 3) We rely on correctly written applications for this to work. Specifically,
+ *    they must be able to deal properly with spurious wakeups. That is,
+ *    they must re-test their condition upon wakeup and wait again if
+ *    the condition is not satisfied.
+ */
+
+void *
+pthread_timechange_handler_np (void *arg)
+     /*
+      * ------------------------------------------------------
+      * DOCPUBLIC
+      *      Broadcasts all CVs to force re-evaluation and
+      *      new timeouts if required.
+      *
+      * PARAMETERS
+      *      NONE
+      *
+      *
+      * DESCRIPTION
+      *      Broadcasts all CVs to force re-evaluation and
+      *      new timeouts if required.
+      *
+      *      This routine may be passed directly to pthread_create()
+      *      as a new thread in order to run asynchronously.
+      *
+      *
+      * RESULTS
+      *              0               successfully broadcast all CVs
+      *              EAGAIN          Not all CVs were broadcast
+      *
+      * ------------------------------------------------------
+      */
+{
+  int result = 0;
+  pthread_cond_t cv;
+  ptw32_mcs_local_node_t node;
+
+  ptw32_mcs_lock_acquire(&ptw32_cond_list_lock, &node);
+
+  cv = ptw32_cond_list_head;
+
+  while (cv != NULL && 0 == result)
+    {
+      result = pthread_cond_broadcast (&cv);
+      cv = cv->next;
+    }
+
+  ptw32_mcs_lock_release(&node);
+
+  return (void *) (size_t) (result != 0 ? EAGAIN : 0);
+}
-- 
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