SGI hash_map extension bug with allocators

[Alex <dazhbog at chat dot ru>]

Hello libstdc++,

  Does anyone tell me how to fix the problem with SGI extension
  hash_map allocators?
  
  The problem is in followed:
  1) Definition of hash_map class looks like
     hash_map <key_type, value_type, hasher, equality, allocator_type>
     By default allocator_type = allocator<value_type>.
  2) hash_map has member _M_ht of hashtable <pair <key_type,
     value_type>, hasher, extractor, equality, allocator_type> type.
  3) hashtable has member _M_buckets of vector<_Node*,
     _M_buckets_allocator_type > type, where _Node is a typedef of
     _Hastable_node struct.

  The case is in that all allocators in hash_map, hashtable and
  vector<_Node*> have the same type, allocator<hash_map::value_type>.
  And even more the same allocator is used to create _Node object
  inside hashtable method. MSVC 6.0 compiler gets an error message of
  inconsistent types.

  Actualy in hash_map class only two types of allocators are needed
  and both are used in hashtable class.
  - First to construct hash table of vector<_Node*> itself
  (should be allocator<hashtable::value_type*> =
  allocator<pair<hash_map::key_type, hash_map::value_type>*>).
  - Second to create _Node object allocator<_Node>.allocate( 1, NULL )
  (should be allocator<_Node> =
  allocator<_Hastable_node<hashtable::value_type>> =
  allocator<_Hastable_node<pair<hash_map::key_type,hash_map::value_type>>>).

  But allocator which came from hash_map is
  allocator<hash_map::value_type>, i.e. absolutely incorrect
  allocator. Instead of it one of the two mentioned above allocators
  should be used but which one?

  How to resolve such a problem? In my task I used to take
  allocator<pair<key_type,value_type> as a default allocator for
  hash_map class to create _Node objects and to construct
  vector<_Node*> with STL default allocator for <_Node*>. But such
  method is in contradiction with the main principle of STL allocators
  because vector<> is not possible to create here with user defined
  allocator.


-- 
Best regards,
 Alex                          mailto:dazhbog@chat.ru