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Diffstat (limited to 'sal/inc/osl/doublecheckedlocking.h')
-rw-r--r-- | sal/inc/osl/doublecheckedlocking.h | 75 |
1 files changed, 0 insertions, 75 deletions
diff --git a/sal/inc/osl/doublecheckedlocking.h b/sal/inc/osl/doublecheckedlocking.h deleted file mode 100644 index 64b07d46cd6c..000000000000 --- a/sal/inc/osl/doublecheckedlocking.h +++ /dev/null @@ -1,75 +0,0 @@ -/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ -/* - * This file is part of the LibreOffice project. - * - * This Source Code Form is subject to the terms of the Mozilla Public - * License, v. 2.0. If a copy of the MPL was not distributed with this - * file, You can obtain one at http://mozilla.org/MPL/2.0/. - * - * This file incorporates work covered by the following license notice: - * - * Licensed to the Apache Software Foundation (ASF) under one or more - * contributor license agreements. See the NOTICE file distributed - * with this work for additional information regarding copyright - * ownership. The ASF licenses this file to you under the Apache - * License, Version 2.0 (the "License"); you may not use this file - * except in compliance with the License. You may obtain a copy of - * the License at http://www.apache.org/licenses/LICENSE-2.0 . - */ - -#ifndef INCLUDED_OSL_DOUBLECHECKEDLOCKING_H -#define INCLUDED_OSL_DOUBLECHECKEDLOCKING_H - -#if defined __cplusplus -extern "C" { -#endif /* __cplusplus */ - -/** A platform specific macro needed to make double-checked locking work. - - See - <http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html> - for a description of double-checked locking, why it is broken, and how it - can be fixed. On platforms where it is necessary, this macro will expand - to some memory barrier instruction. On many platforms, double-checked - locking works as it is, though, so on those platforms this macro will be - empty. This is a macro instead of a (C++ inline) function to allow for - maximum performance in both C and C++. - - If possible, use the rtl_Instance template instead of explicitly spelling - out the double-checked locking pattern. There are few cases where you - will have to spell it out explicitly (e.g., the logic of a certain - instance of the pattern is too complex to be mapped to the template, or - some compiler refuses to compile a template instantiation due to internal - compiler errors), though, and you should always call this macro at the - right places then: - - static T * pInstance = 0; - - T * p = pInstance; - if (!p) - { - Guard aGuard(aMutex); - p = pInstance; - if (!p) - { - p = ...; - OSL_DOUBLE_CHECKED_LOCKING_MEMORY_BARRIER(); - pInstance = p; - } - } - else - OSL_DOUBLE_CHECKED_LOCKING_MEMORY_BARRIER(); - return p; - - One extra advantage of this macro is that it makes it easier to find all - places where double-checked locking is used. - */ -#define OSL_DOUBLE_CHECKED_LOCKING_MEMORY_BARRIER() /* empty */ - -#if defined __cplusplus -} -#endif /* __cplusplus */ - -#endif /* INCLUDED_OSL_DOUBLECHECKEDLOCKING_H */ - -/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |