Where Is color_map defined in BGL?

Example code from BGL:

breadth_first_search(g, vertex(s, g), color_map(get(&VertexProps::color, g)).visitor(vis));

Wh开发者_运维技巧at is color_map, where is it defined? And where is it documented?

It's defined as a named parameter in http://www.boost.org/doc/libs/1_46_0/boost/graph/named_function_params.hpp

If you have access to the src-code I would suggest that you take a look at ctags This remarkable tool will index the code for you and allow instant jumping the the definition/implementation of everything indexed in the src-tree.

Another approach is to use ack to search for it.

Could it be the two bit color map from that library?