[boost] [BGL] How can I measure the memory used by a Boost graph ?

Hi, I have a graph defined as follow: struct NodeData{ /*...*/ }; struct EdgeData{ /*...*/ }; typedef adjacency_list<setS, setS, undirectedS, NodeData, EdgeData> MyGraph; MyGraph G; This graph is updated iteratively (by adding/deleting some edges/vertices). At each iteration, I want to evaluate the memory space occupied by this graph G. How can I do that ?