posix_locking.cpp

Go to the documentation of this file.

/******************************************************************************
** Copyright © 2004 by J.M.McGuiness, coder@hussar.me.uk
**
** 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 2.1 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; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
 
#include "../core/hp_timer.hpp"
#include "posix_locking.hpp"
 
namespace jmmcg { namespace LIBJMMCG_VER_NAMESPACE { namespace ppd { namespace pthreads {
 
anon_semaphore::lock_result_type
anon_semaphore::lock(const timeout_type period) noexcept(false) {
   using timer_t=hp_timer<ppd::generic_traits::api_type::posix_pthreads, heavyweight_threading>;
 
   if (period==0) {
      return try_lock();
   } else if (period<lock_traits::infinite_timeout()) {
      static const timer_t time;
      timer_t::time_utc_t now=time.current_time();
      now.tv_nsec+=(period%1000)*1000000;
      now.tv_sec+=period/1000+now.tv_nsec/1000000000;
      now.tv_nsec=now.tv_nsec%1000000000;
      assert(now.tv_nsec>=0);
      assert(now.tv_nsec<1000000000);
      if (sem_timedwait(&sem, &now)==-1) {
         switch (errno) {
         case ETIMEDOUT: return lock_traits::atom_unset;
         case EINTR: return lock_traits::atom_interrupted;
         case EAGAIN: return lock_traits::atom_max_recurse;
         case EINVAL:
         default: return lock_traits::atom_abandoned;
         };
      }
      return lock_traits::atom_set;
   } else {
      return lock();
   }
}
 
} } } }