text: //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
  //  This source code is licensed under both the GPLv2 (found in the
  //  COPYING file in the root directory) and Apache 2.0 License
  //  (found in the LICENSE.Apache file in the root directory).
  //
  // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file. See the AUTHORS file for names of contributors.
  
  #include <mutex>
  
  #include <rocksdb/env.h>
  #include "port/win/env_win.h"
  #include "util/compression_context_cache.h"
  #include "util/sync_point.h"
  #include "util/thread_local.h"
  
  namespace rocksdb {
  namespace port {
  
  // We choose not to destroy the env because joining the threads from the
  // system loader
  //    which destroys the statics (same as from DLLMain) creates a system loader
  //    dead-lock.
  //    in this manner any remaining threads are terminated OK.
  namespace {
    std::once_flag winenv_once_flag;
    Env* envptr;
  };
  }
  
  Env* Env::Default() {
    using namespace port;
    ThreadLocalPtr::InitSingletons();
    CompressionContextCache::InitSingleton();
    INIT_SYNC_POINT_SINGLETONS();
    std::call_once(winenv_once_flag, []() { envptr = new WinEnv(); });
    return envptr;
  }
  
  }
  