diff --git a/include/__split_buffer b/include/__split_buffer
index c68349e..b638cb0 100644
--- a/include/__split_buffer
+++ b/include/__split_buffer
@@ -153,7 +153,7 @@ public:
 
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_front() { __destruct_at_begin(__begin_ + 1); }
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void pop_back() { __destruct_at_end(__end_ - 1); }
-
+  void __uninitialized_at_end(size_type __n);
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n);
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __construct_at_end(size_type __n, const_reference __x);
 
@@ -236,6 +236,11 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __split_buffer<_Tp, _Allocator>::__invariants
   return true;
 }
 
+template <class _Tp, class _Allocator>
+void __split_buffer<_Tp, _Allocator>::__uninitialized_at_end(size_type __n) {
+  this->__end_ += __n;
+}
+
 //  Default constructs __n objects starting at __end_
 //  throws if construction throws
 //  Precondition:  __n > 0