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glib/gobject/gatomicarray.h

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Add GAtomicArray for RCU-style lockless updates This adds supports for a lock-less a non-shrinking growable array. You can use it to do reads using no locks, as long as your read-code can handle that during the read transaction the object can be modified by another writer (but it will not change size or be freed), and you can only trust the result once the transaction has finished successfully. This doesn't free things like RCU normally does, instead it pushes the memory on a free list that is reused for other atomic arrays.
2009-09-09 16:47:44 +02:00
/* GObject - GLib Type, Object, Parameter and Signal Library
* Copyright (C) 2009 Benjamin Otte <otte@gnome.org>
*
Add SPDX license headers for LGPL-2.1-or-later to various files These have all been added manually, as I’ve finished all the files which I can automatically detect. All the license headers in this commit are for LGPL-2.1-or-later, and all have been double-checked against the license paragraph in the file header. Signed-off-by: Philip Withnall <pwithnall@endlessos.org> Helps: #1415
2022-06-01 13:44:23 +02:00
* SPDX-License-Identifier: LGPL-2.1-or-later
*
Add GAtomicArray for RCU-style lockless updates This adds supports for a lock-less a non-shrinking growable array. You can use it to do reads using no locks, as long as your read-code can handle that during the read transaction the object can be modified by another writer (but it will not change size or be freed), and you can only trust the result once the transaction has finished successfully. This doesn't free things like RCU normally does, instead it pushes the memory on a free list that is reused for other atomic arrays.
2009-09-09 16:47:44 +02:00
* 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
gobject/: LGPLv2+ -> LGPLv2.1+ All gobject/*.{c,h} files have been processed. gmarshal.c and gmarshal.h don't have a license header. https://bugzilla.gnome.org/show_bug.cgi?id=776504
2017-01-05 14:09:06 +01:00
* version 2.1 of the License, or (at your option) any later version.
Add GAtomicArray for RCU-style lockless updates This adds supports for a lock-less a non-shrinking growable array. You can use it to do reads using no locks, as long as your read-code can handle that during the read transaction the object can be modified by another writer (but it will not change size or be freed), and you can only trust the result once the transaction has finished successfully. This doesn't free things like RCU normally does, instead it pushes the memory on a free list that is reused for other atomic arrays.
2009-09-09 16:47:44 +02:00
*
* 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
Updated FSF's address
2014-01-23 12:58:29 +01:00
* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
Add GAtomicArray for RCU-style lockless updates This adds supports for a lock-less a non-shrinking growable array. You can use it to do reads using no locks, as long as your read-code can handle that during the read transaction the object can be modified by another writer (but it will not change size or be freed), and you can only trust the result once the transaction has finished successfully. This doesn't free things like RCU normally does, instead it pushes the memory on a free list that is reused for other atomic arrays.
2009-09-09 16:47:44 +02:00
*/
Move single-include guards inside include guards gcc has optimizations for include guards that only work if they are outermost in the the header. https://bugzilla.gnome.org/show_bug.cgi?id=689810
2012-12-28 05:43:14 +01:00
#ifndef __G_ATOMIC_ARRAY_H__
#define __G_ATOMIC_ARRAY_H__
Add GAtomicArray for RCU-style lockless updates This adds supports for a lock-less a non-shrinking growable array. You can use it to do reads using no locks, as long as your read-code can handle that during the read transaction the object can be modified by another writer (but it will not change size or be freed), and you can only trust the result once the transaction has finished successfully. This doesn't free things like RCU normally does, instead it pushes the memory on a free list that is reused for other atomic arrays.
2009-09-09 16:47:44 +02:00
#if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
#error "Only <glib-object.h> can be included directly."
#endif
#include <glib/glib.h>
G_BEGIN_DECLS
#define G_ATOMIC_ARRAY_DATA_SIZE(mem) (*((gsize *) (mem) - 1))
typedef struct _GAtomicArray GAtomicArray;
struct _GAtomicArray {
gatomicarray: Drop volatile qualifier from GAtomicArray API This is an API break, but it should not affect third party code since that code should not be interacting with the `data` member in a way that invokes its `volatile` qualifier (such as copying to an intermediate variable). Signed-off-by: Philip Withnall <pwithnall@endlessos.org> Helps: #600
2020-11-11 20:19:20 +01:00
gpointer data; /* elements - atomic */
Add GAtomicArray for RCU-style lockless updates This adds supports for a lock-less a non-shrinking growable array. You can use it to do reads using no locks, as long as your read-code can handle that during the read transaction the object can be modified by another writer (but it will not change size or be freed), and you can only trust the result once the transaction has finished successfully. This doesn't free things like RCU normally does, instead it pushes the memory on a free list that is reused for other atomic arrays.
2009-09-09 16:47:44 +02:00
};
void _g_atomic_array_init (GAtomicArray *array);
gpointer _g_atomic_array_copy (GAtomicArray *array,
gsize header_size,
gsize additional_element_size);
void _g_atomic_array_update (GAtomicArray *array,
gpointer new_data);
#define G_ATOMIC_ARRAY_GET_LOCKED(_array, _type) ((_type *)((_array)->data))
#define G_ATOMIC_ARRAY_DO_TRANSACTION(_array, _type, _C_) G_STMT_START { \
gatomicarray: Drop volatile qualifier from GAtomicArray API This is an API break, but it should not affect third party code since that code should not be interacting with the `data` member in a way that invokes its `volatile` qualifier (such as copying to an intermediate variable). Signed-off-by: Philip Withnall <pwithnall@endlessos.org> Helps: #600
2020-11-11 20:19:20 +01:00
gpointer *_datap = &(_array)->data; \
Add GAtomicArray for RCU-style lockless updates This adds supports for a lock-less a non-shrinking growable array. You can use it to do reads using no locks, as long as your read-code can handle that during the read transaction the object can be modified by another writer (but it will not change size or be freed), and you can only trust the result once the transaction has finished successfully. This doesn't free things like RCU normally does, instead it pushes the memory on a free list that is reused for other atomic arrays.
2009-09-09 16:47:44 +02:00
_type *transaction_data, *__check; \
\
__check = g_atomic_pointer_get (_datap); \
do { \
transaction_data = __check; \
{_C_;} \
__check = g_atomic_pointer_get (_datap); \
} while (transaction_data != __check); \
} G_STMT_END
G_END_DECLS
#endif /* __G_ATOMIC_ARRAY_H__ */
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