diff --git a/include/boost/detail/atomic_count_gcc.hpp b/include/boost/detail/atomic_count_gcc.hpp
index b4a46ce..8761b80 100644
--- a/include/boost/detail/atomic_count_gcc.hpp
+++ b/include/boost/detail/atomic_count_gcc.hpp
@@ -38,7 +38,7 @@ public:
 
     long operator--()
     {
-        return !__exchange_and_add(&value_, -1);
+        return __exchange_and_add(&value_, -1) - 1;
     }
 
     operator long() const