File: //usr/include/glib-2.0/glib/gatomic.h
/*
* Copyright © 2011 Ryan Lortie
*
* 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
* version 2.1 of the License, or (at your option) any later version.
*
* 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 Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
* Author: Ryan Lortie <desrt@desrt.ca>
*/
#ifndef __G_ATOMIC_H__
#define __G_ATOMIC_H__
#if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
#error "Only <glib.h> can be included directly."
#endif
#include <glib/gtypes.h>
G_BEGIN_DECLS
GLIB_AVAILABLE_IN_ALL
gint g_atomic_int_get (const volatile gint *atomic);
GLIB_AVAILABLE_IN_ALL
void g_atomic_int_set (volatile gint *atomic,
gint newval);
GLIB_AVAILABLE_IN_ALL
void g_atomic_int_inc (volatile gint *atomic);
GLIB_AVAILABLE_IN_ALL
gboolean g_atomic_int_dec_and_test (volatile gint *atomic);
GLIB_AVAILABLE_IN_ALL
gboolean g_atomic_int_compare_and_exchange (volatile gint *atomic,
gint oldval,
gint newval);
GLIB_AVAILABLE_IN_ALL
gint g_atomic_int_add (volatile gint *atomic,
gint val);
GLIB_AVAILABLE_IN_2_30
guint g_atomic_int_and (volatile guint *atomic,
guint val);
GLIB_AVAILABLE_IN_2_30
guint g_atomic_int_or (volatile guint *atomic,
guint val);
GLIB_AVAILABLE_IN_ALL
guint g_atomic_int_xor (volatile guint *atomic,
guint val);
GLIB_AVAILABLE_IN_ALL
gpointer g_atomic_pointer_get (const volatile void *atomic);
GLIB_AVAILABLE_IN_ALL
void g_atomic_pointer_set (volatile void *atomic,
gpointer newval);
GLIB_AVAILABLE_IN_ALL
gboolean g_atomic_pointer_compare_and_exchange (volatile void *atomic,
gpointer oldval,
gpointer newval);
GLIB_AVAILABLE_IN_ALL
gssize g_atomic_pointer_add (volatile void *atomic,
gssize val);
GLIB_AVAILABLE_IN_2_30
gsize g_atomic_pointer_and (volatile void *atomic,
gsize val);
GLIB_AVAILABLE_IN_2_30
gsize g_atomic_pointer_or (volatile void *atomic,
gsize val);
GLIB_AVAILABLE_IN_ALL
gsize g_atomic_pointer_xor (volatile void *atomic,
gsize val);
GLIB_DEPRECATED_IN_2_30_FOR(g_atomic_int_add)
gint g_atomic_int_exchange_and_add (volatile gint *atomic,
gint val);
G_END_DECLS
#if defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
/* We prefer the new C11-style atomic extension of GCC if available */
#if defined(__ATOMIC_SEQ_CST)
#define g_atomic_int_get(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
gint gaig_temp; \
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
__atomic_load ((gint *)(atomic), &gaig_temp, __ATOMIC_SEQ_CST); \
(gint) gaig_temp; \
}))
#define g_atomic_int_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
gint gais_temp = (gint) (newval); \
(void) (0 ? *(atomic) ^ (newval) : 1); \
__atomic_store ((gint *)(atomic), &gais_temp, __ATOMIC_SEQ_CST); \
}))
#if defined(g_has_typeof)
#define g_atomic_pointer_get(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
__typeof__(*(atomic)) gapg_temp_newval; \
__typeof__((atomic)) gapg_temp_atomic = (atomic); \
__atomic_load (gapg_temp_atomic, &gapg_temp_newval, __ATOMIC_SEQ_CST); \
gapg_temp_newval; \
}))
#define g_atomic_pointer_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
__typeof__((atomic)) gaps_temp_atomic = (atomic); \
__typeof__(*(atomic)) gaps_temp_newval = (newval); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
__atomic_store (gaps_temp_atomic, &gaps_temp_newval, __ATOMIC_SEQ_CST); \
}))
#else /* if !defined(g_has_typeof) */
#define g_atomic_pointer_get(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
gpointer gapg_temp_newval; \
gpointer *gapg_temp_atomic = (gpointer *)(atomic); \
__atomic_load (gapg_temp_atomic, &gapg_temp_newval, __ATOMIC_SEQ_CST); \
gapg_temp_newval; \
}))
#define g_atomic_pointer_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
gpointer *gaps_temp_atomic = (gpointer *)(atomic); \
gpointer gaps_temp_newval = (gpointer)(newval); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
__atomic_store (gaps_temp_atomic, &gaps_temp_newval, __ATOMIC_SEQ_CST); \
}))
#endif /* !defined(g_has_typeof) */
#define g_atomic_int_inc(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
(void) __atomic_fetch_add ((atomic), 1, __ATOMIC_SEQ_CST); \
}))
#define g_atomic_int_dec_and_test(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
__atomic_fetch_sub ((atomic), 1, __ATOMIC_SEQ_CST) == 1; \
}))
#define g_atomic_int_compare_and_exchange(atomic, oldval, newval) \
(G_GNUC_EXTENSION ({ \
gint gaicae_oldval = (oldval); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (newval) ^ (oldval) : 1); \
__atomic_compare_exchange_n ((atomic), &gaicae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
}))
#define g_atomic_int_add(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (val) : 1); \
(gint) __atomic_fetch_add ((atomic), (val), __ATOMIC_SEQ_CST); \
}))
#define g_atomic_int_and(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (val) : 1); \
(guint) __atomic_fetch_and ((atomic), (val), __ATOMIC_SEQ_CST); \
}))
#define g_atomic_int_or(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (val) : 1); \
(guint) __atomic_fetch_or ((atomic), (val), __ATOMIC_SEQ_CST); \
}))
#define g_atomic_int_xor(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (val) : 1); \
(guint) __atomic_fetch_xor ((atomic), (val), __ATOMIC_SEQ_CST); \
}))
#define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof (oldval) == sizeof (gpointer)); \
__typeof__ ((oldval)) gapcae_oldval = (oldval); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
__atomic_compare_exchange_n ((atomic), &gapcae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
}))
#define g_atomic_pointer_add(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gssize) __atomic_fetch_add ((atomic), (val), __ATOMIC_SEQ_CST); \
}))
#define g_atomic_pointer_and(atomic, val) \
(G_GNUC_EXTENSION ({ \
volatile gsize *gapa_atomic = (volatile gsize *) (atomic); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gsize)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gsize) __atomic_fetch_and (gapa_atomic, (val), __ATOMIC_SEQ_CST); \
}))
#define g_atomic_pointer_or(atomic, val) \
(G_GNUC_EXTENSION ({ \
volatile gsize *gapo_atomic = (volatile gsize *) (atomic); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gsize)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gsize) __atomic_fetch_or (gapo_atomic, (val), __ATOMIC_SEQ_CST); \
}))
#define g_atomic_pointer_xor(atomic, val) \
(G_GNUC_EXTENSION ({ \
volatile gsize *gapx_atomic = (volatile gsize *) (atomic); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gsize)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gsize) __atomic_fetch_xor (gapx_atomic, (val), __ATOMIC_SEQ_CST); \
}))
#else /* defined(__ATOMIC_SEQ_CST) */
/* We want to achieve __ATOMIC_SEQ_CST semantics here. See
* https://en.cppreference.com/w/c/atomic/memory_order#Constants. For load
* operations, that means performing an *acquire*:
* > A load operation with this memory order performs the acquire operation on
* > the affected memory location: no reads or writes in the current thread can
* > be reordered before this load. All writes in other threads that release
* > the same atomic variable are visible in the current thread.
*
* “no reads or writes in the current thread can be reordered before this load”
* is implemented using a compiler barrier (a no-op `__asm__` section) to
* prevent instruction reordering. Writes in other threads are synchronised
* using `__sync_synchronize()`. It’s unclear from the GCC documentation whether
* `__sync_synchronize()` acts as a compiler barrier, hence our explicit use of
* one.
*
* For store operations, `__ATOMIC_SEQ_CST` means performing a *release*:
* > A store operation with this memory order performs the release operation:
* > no reads or writes in the current thread can be reordered after this store.
* > All writes in the current thread are visible in other threads that acquire
* > the same atomic variable (see Release-Acquire ordering below) and writes
* > that carry a dependency into the atomic variable become visible in other
* > threads that consume the same atomic (see Release-Consume ordering below).
*
* “no reads or writes in the current thread can be reordered after this store”
* is implemented using a compiler barrier to prevent instruction reordering.
* “All writes in the current thread are visible in other threads” is implemented
* using `__sync_synchronize()`; similarly for “writes that carry a dependency”.
*/
#define g_atomic_int_get(atomic) \
(G_GNUC_EXTENSION ({ \
gint gaig_result; \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
gaig_result = (gint) *(atomic); \
__sync_synchronize (); \
__asm__ __volatile__ ("" : : : "memory"); \
gaig_result; \
}))
#define g_atomic_int_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (newval) : 1); \
__sync_synchronize (); \
__asm__ __volatile__ ("" : : : "memory"); \
*(atomic) = (newval); \
}))
#define g_atomic_pointer_get(atomic) \
(G_GNUC_EXTENSION ({ \
gpointer gapg_result; \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
gapg_result = (gpointer) *(atomic); \
__sync_synchronize (); \
__asm__ __volatile__ ("" : : : "memory"); \
gapg_result; \
}))
#define g_atomic_pointer_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
__sync_synchronize (); \
__asm__ __volatile__ ("" : : : "memory"); \
*(atomic) = (__typeof__ (*(atomic))) (gsize) (newval); \
}))
#define g_atomic_int_inc(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
(void) __sync_fetch_and_add ((atomic), 1); \
}))
#define g_atomic_int_dec_and_test(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
__sync_fetch_and_sub ((atomic), 1) == 1; \
}))
#define g_atomic_int_compare_and_exchange(atomic, oldval, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (newval) ^ (oldval) : 1); \
__sync_bool_compare_and_swap ((atomic), (oldval), (newval)) ? TRUE : FALSE; \
}))
#define g_atomic_int_add(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (val) : 1); \
(gint) __sync_fetch_and_add ((atomic), (val)); \
}))
#define g_atomic_int_and(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (val) : 1); \
(guint) __sync_fetch_and_and ((atomic), (val)); \
}))
#define g_atomic_int_or(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (val) : 1); \
(guint) __sync_fetch_and_or ((atomic), (val)); \
}))
#define g_atomic_int_xor(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (val) : 1); \
(guint) __sync_fetch_and_xor ((atomic), (val)); \
}))
#define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
__sync_bool_compare_and_swap ((atomic), (oldval), (newval)) ? TRUE : FALSE; \
}))
#define g_atomic_pointer_add(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gssize) __sync_fetch_and_add ((atomic), (val)); \
}))
#define g_atomic_pointer_and(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gsize) __sync_fetch_and_and ((atomic), (val)); \
}))
#define g_atomic_pointer_or(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gsize) __sync_fetch_and_or ((atomic), (val)); \
}))
#define g_atomic_pointer_xor(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gsize) __sync_fetch_and_xor ((atomic), (val)); \
}))
#endif /* !defined(__ATOMIC_SEQ_CST) */
#else /* defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4) */
#define g_atomic_int_get(atomic) \
(g_atomic_int_get ((gint *) (atomic)))
#define g_atomic_int_set(atomic, newval) \
(g_atomic_int_set ((gint *) (atomic), (gint) (newval)))
#define g_atomic_int_compare_and_exchange(atomic, oldval, newval) \
(g_atomic_int_compare_and_exchange ((gint *) (atomic), (oldval), (newval)))
#define g_atomic_int_add(atomic, val) \
(g_atomic_int_add ((gint *) (atomic), (val)))
#define g_atomic_int_and(atomic, val) \
(g_atomic_int_and ((guint *) (atomic), (val)))
#define g_atomic_int_or(atomic, val) \
(g_atomic_int_or ((guint *) (atomic), (val)))
#define g_atomic_int_xor(atomic, val) \
(g_atomic_int_xor ((guint *) (atomic), (val)))
#define g_atomic_int_inc(atomic) \
(g_atomic_int_inc ((gint *) (atomic)))
#define g_atomic_int_dec_and_test(atomic) \
(g_atomic_int_dec_and_test ((gint *) (atomic)))
#define g_atomic_pointer_get(atomic) \
(g_atomic_pointer_get (atomic))
#define g_atomic_pointer_set(atomic, newval) \
(g_atomic_pointer_set ((atomic), (gpointer) (newval)))
#define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
(g_atomic_pointer_compare_and_exchange ((atomic), (gpointer) (oldval), (gpointer) (newval)))
#define g_atomic_pointer_add(atomic, val) \
(g_atomic_pointer_add ((atomic), (gssize) (val)))
#define g_atomic_pointer_and(atomic, val) \
(g_atomic_pointer_and ((atomic), (gsize) (val)))
#define g_atomic_pointer_or(atomic, val) \
(g_atomic_pointer_or ((atomic), (gsize) (val)))
#define g_atomic_pointer_xor(atomic, val) \
(g_atomic_pointer_xor ((atomic), (gsize) (val)))
#endif /* defined(__GNUC__) && defined(G_ATOMIC_OP_USE_GCC_BUILTINS) */
#endif /* __G_ATOMIC_H__ */