[glib: 4/7] gatomic: Support atomic compare_and_exchange macros on older C++ standard versions

[Philip Withnall <pwithnall src gnome org>]

commit a0f200593ca8343a1ed8bb9868924d1ced13f12b
Author: Damjan Jovanovic <damjan jov gmail com>
Date:   Mon Aug 22 17:18:23 2022 +0200

    gatomic: Support atomic compare_and_exchange macros on older C++ standard versions
    
    The fix in ad23894c1595482cdc10c17a4070a977e396ca4a 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.

 glib/gatomic.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/glib/gatomic.h b/glib/gatomic.h
index 11d319edcc..e1b5d23913 100644
--- a/glib/gatomic.h
+++ b/glib/gatomic.h
@@ -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));                  \