configVariableBool.cxx

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file configVariableBool.cxx
 * @author drose
 * @date 2004-10-20
 */
 
#include "configVariableBool.h"
#include "mutexImpl.h"
 
/**
 * Refreshes the cached value.
 */
void ConfigVariableBool::
reload_value() const {
  // NB. MSVC doesn't guarantee that this mutex is initialized in a
  // thread-safe manner.  But chances are that the first time this is called
  // is at static init time, when there is no risk of data races.
 
  // This needs to be a recursive mutex, because get_bool_word() may end up
  // indirectly querying another bool config variable.
  static ReMutexImpl lock;
  lock.lock();
 
  // We check again for cache validity since another thread may have beaten
  // us to the punch while we were waiting for the lock.
  if (!is_cache_valid(_local_modified)) {
    _cache = get_bool_word(0);
    mark_cache_valid(_local_modified);
  }
 
  lock.unlock();
}