/* * 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;  EnterCriticalSection (&ptw32_cond_list_lock);  cv = ptw32_cond_list_head;  while (cv != NULL && 0 == result)    {      result = pthread_cond_broadcast (&cv);      cv = cv->next;    }  LeaveCriticalSection (&ptw32_cond_list_lock);  return (void *) (result != 0 ? EAGAIN : 0);}