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-rw-r--r--osdep/atomic.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/osdep/atomic.h b/osdep/atomic.h
index 85773cbcb5..9e1c5be721 100644
--- a/osdep/atomic.h
+++ b/osdep/atomic.h
@@ -74,6 +74,13 @@ extern pthread_mutex_t mp_atomic_mutex;
#define atomic_fetch_add(a, b) atomic_fetch_op(a, b, +)
#define atomic_fetch_and(a, b) atomic_fetch_op(a, b, &)
#define atomic_fetch_or(a, b) atomic_fetch_op(a, b, |)
+#define atomic_exchange(p, new) \
+ ({ __typeof__(p) p_ = (p); \
+ pthread_mutex_lock(&mp_atomic_mutex); \
+ __typeof__(p_->v) res_ = p_->v; \
+ p_->v = (new); \
+ pthread_mutex_unlock(&mp_atomic_mutex); \
+ res_; })
#define atomic_compare_exchange_strong(p, old, new) \
({ __typeof__(p) p_ = (p); \
__typeof__(old) old_ = (old); \