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gatomic: Support atomic compare_and_exchange macros on older C++ standard versions

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The fix in ad23894c15 only works for
__cplusplus >= 201103L, but older C++ standards are not always less strict,
and still fail to compile the g_atomic_int_compare_and_exchange() and
g_atomic_pointer_compare_and_exchange() macros.

Apply that fix to all C++ standard versions.

Even if this implies using functions that have been added as part of
C++11 specification, this is safe because we wouldn't ever try to use the
`__atomic_...()` APIs if `__ATOMIC_SEQ_CST` is not defined, and that's part
of the very same API.
This commit is contained in:
Damjan Jovanovic 2022-08-22 17:18:23 +02:00 committed by Marco Trevisan (Treviño)
parent 0abb82498e
commit a0f200593c
1 changed files with 4 additions and 4 deletions
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8
glib/gatomic.h
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@ -170,7 +170,7 @@ G_END_DECLS
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
__atomic_fetch_sub ((atomic), 1, __ATOMIC_SEQ_CST) == 1; \
}))
#if defined(glib_typeof) && defined(__cplusplus) && __cplusplus >= 201103L
#if defined(glib_typeof) && defined(__cplusplus)
/* See comments below about equivalent g_atomic_pointer_compare_and_exchange()
* shenanigans for type-safety when compiling in C++ mode. */
#define g_atomic_int_compare_and_exchange(atomic, oldval, newval) \
@ -180,7 +180,7 @@ G_END_DECLS
(void) (0 ? *(atomic) ^ (newval) ^ (oldval) : 1); \
__atomic_compare_exchange_n ((atomic), &gaicae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
}))
#else /* if !(defined(glib_typeof) && defined(__cplusplus) && __cplusplus >= 201103L) */
#else /* if !(defined(glib_typeof) && defined(__cplusplus)) */
#define g_atomic_int_compare_and_exchange(atomic, oldval, newval) \
(G_GNUC_EXTENSION ({ \
gint gaicae_oldval = (oldval); \
@ -230,7 +230,7 @@ G_END_DECLS
(guint) __atomic_fetch_xor ((atomic), (val), __ATOMIC_SEQ_CST); \
}))
#if defined(glib_typeof) && defined(__cplusplus) && __cplusplus >= 201103L
#if defined(glib_typeof) && defined(__cplusplus)
/* This is typesafe because we check we can assign oldval to the type of
* (*atomic). Unfortunately it can only be done in C++ because gcc/clang warn
* when atomic is volatile and not oldval, or when atomic is gsize* and oldval
@ -247,7 +247,7 @@ G_END_DECLS
(void) (0 ? (gpointer) *(atomic) : NULL); \
__atomic_compare_exchange_n ((atomic), &gapcae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
}))
#else /* if !(defined(glib_typeof) && defined(__cplusplus) && __cplusplus >= 201103L) */
#else /* if !(defined(glib_typeof) && defined(__cplusplus) */
#define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof (oldval) == sizeof (gpointer)); \