/*

 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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#ifndef SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP

#define SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP

#include "utilities/top.hpp"

// forward-decl as we can't have an include cycle

class Thread;

// Wrapper class for library-based (as opposed to compiler-based)

// thread-local storage (TLS). All platforms require this for

// signal-handler based TLS access (which while not strictly async-signal

// safe in theory, is and has-been for a long time, in practice).

// Platforms without compiler-based TLS (i.e. __thread storage-class modifier)

// will use this implementation for all TLS access - see thread.hpp/cpp

class ThreadLocalStorage : AllStatic {

 // Exported API

 public:

  static Thread* thread(); // return current thread, if attached

  static void    set_thread(Thread* thread); // set current thread

  static void    init();

  static bool    is_initialized(); // can't use TLS prior to initialization

};

#endif // SHARE_VM_RUNTIME_THREADLOCALSTORAGE_HPP