diff --git a/doc/interprocess.qbk b/doc/interprocess.qbk
index 5313a6c..3ccc12b 100644
--- a/doc/interprocess.qbk
+++ b/doc/interprocess.qbk
@@ -6809,6 +6809,7 @@ thank them:
    * [@https://github.com/boostorg/interprocess/pull/83    GitHub #83  (['"Add BOOST_INTERPROCESS_FORCE_NATIVE_EMULATION option"])].
    * [@https://github.com/boostorg/interprocess/pull/92    GitHub #92  (['"bufferstream: Correct MSVC compilation warning"])].
    * [@https://github.com/boostorg/interprocess/pull/106   GitHub #106 (['"Use fallocate on truncate_file"])].
+   * [@https://github.com/boostorg/interprocess/issues/120 GitHub #120 (['"segment_manager customization"])].
    * [@https://github.com/boostorg/interprocess/issues/122 GitHub #122 (['"Mark constructors/assignment/swap noexcept where possible"])].
    * [@https://github.com/boostorg/interprocess/issues/126 GitHub #126 (['"_ReadWriteBarrier is deprecated warning when compiling with clang-cl.exe"])].
 
diff --git a/include/boost/interprocess/segment_manager.hpp b/include/boost/interprocess/segment_manager.hpp
index 14b11cb..283cd32 100644
--- a/include/boost/interprocess/segment_manager.hpp
+++ b/include/boost/interprocess/segment_manager.hpp
@@ -127,6 +127,20 @@ class segment_manager_base
    void * allocate (size_type nbytes, const std::nothrow_t &)
    {  return MemoryAlgorithm::allocate(nbytes);   }
 
+   //!Returns a reference to the internal memory algorithm.
+   //!This function is useful for custom memory algorithms that
+   //!need additional configuration options after construction. Never throws.
+   //!This function should be only used by advanced users.
+   MemoryAlgorithm &get_memory_algorithm()
+   {  return static_cast<MemoryAlgorithm&>(*this);   }
+
+   //!Returns a const reference to the internal memory algorithm.
+   //!This function is useful for custom memory algorithms that
+   //!need additional configuration options after construction. Never throws.
+   //!This function should be only used by advanced users.
+   const MemoryAlgorithm &get_memory_algorithm() const
+   {  return static_cast<const MemoryAlgorithm&>(*this);   }
+
    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 
    //Experimental. Dont' use.
diff --git a/test/segment_manager_test.cpp b/test/segment_manager_test.cpp
index a440def..f22eca0 100644
--- a/test/segment_manager_test.cpp
+++ b/test/segment_manager_test.cpp
@@ -289,7 +289,7 @@ bool test_segment_manager()
             return false;
          typename SegmentManager::const_named_iterator nb(seg_mgr->named_begin());
          typename SegmentManager::const_named_iterator ne(seg_mgr->named_end());
-         for(std::size_t i = 0, imax = seg_mgr->get_num_named_objects(); i != imax; ++i){ ++nb; }
+         for(std::size_t j = 0, imax = seg_mgr->get_num_named_objects(); j != imax; ++j){ ++nb; }
          if(nb != ne)
             return false;
          seg_mgr->destroy_ptr(uint_object);
@@ -379,7 +379,7 @@ bool test_segment_manager()
             return false;
          typename SegmentManager::const_unique_iterator nb(seg_mgr->unique_begin());
          typename SegmentManager::const_unique_iterator ne(seg_mgr->unique_end());
-         for(std::size_t i = 0, imax = seg_mgr->get_num_unique_objects(); i != imax; ++i){ ++nb; }
+         for(std::size_t j = 0, imax = seg_mgr->get_num_unique_objects(); j != imax; ++j){ ++nb; }
          if(nb != ne)
             return false;
          seg_mgr->destroy_ptr(uint_object);
@@ -436,6 +436,18 @@ bool test_segment_manager()
       if(!seg_mgr->all_memory_deallocated())
          return false;
    }
+   {//test get_memory_algorithm
+      {
+         typename SegmentManager::memory_algorithm & mem_algo =
+            seg_mgr->get_memory_algorithm();
+         boost::ignore_unused(mem_algo);
+      }
+      {
+         const typename SegmentManager::memory_algorithm & mem_algo =
+            const_cast<const SegmentManager*>(seg_mgr)->get_memory_algorithm();
+         boost::ignore_unused(mem_algo);
+      }
+   }
    return true;
 }