#

    adjacency_list_traits<EdgeList, VertexList, Directed>

This class provides an alternate method for accessing some of the associated types of the `adjacency_list` class. The main reason for this class is that sometimes one would like to create graph properties whose values are vertex or edge descriptors. If you try to use `graph_traits` for this you will run into a problem with mutually recursive types. To get around this problem, the `adjacency_list_traits` class is provided, which gives the user access to the vertex and edge descriptor types without requiring the user to provide the property types for the graph.

      template <class EdgeList, class VertexList, class Directed>
      struct adjacency_list_traits {
        typedef ... vertex_descriptor;
        typedef ... edge_descriptor;
        typedef ... directed_category;
        typedef ... edge_parallel_category;
      };

### Where Defined

`boost/graph/adjacency_list.hpp`

### Template Parameters

Parameter | Description | Default
--- | --- | ---
`EdgeList` | The selector type for the edge container implementation. | `vecS`
`VertexList` | The selector type for the vertex container implementation. | `vecS`
`Directed` | The selector type whether the graph is directed or undirected. | `directedS`

### Model of

DefaultConstructible and Assignable

### Type Requirements

Under construction.

## Members

Member | Description
--- | ---
`vertex_descriptor` | The type for the objects used to identify vertices in the graph.
`edge_descriptor` | The type for the objects used to identify edges in the graph.
`directed_category` | This says whether the graph is undirected (`undirected_tag`) or directed (`directed_tag`).
`edge_parallel_category` | This says whether the graph allows parallel edges to be inserted (`allow_parallel_edge_tag`) or if it automatically removes parallel edges (`disallow_parallel_edge_tag`).

### See Also

`adjacency_list`

Copyright © 2000-2001 | Jeremy Siek, Indiana University (jsiek@osl.iu.edu) Lie-Quan Lee, Indiana University (llee@cs.indiana.edu) Andrew Lumsdaine, Indiana University (lums@osl.iu.edu)