The BGL implementation of breadth-first search uses a dedicated color map. I had the following idea: Some algorithms don't need to distinguish black/gray, but have an unused value in e.g. a distance map, e.g. -1, to which the map can be initialised. So I tried to write a map adapter which can be passed such a map together with the value indicating "white". This adapter will return white whenever the value in the underlying map equals this value, black otherwise. Unfortunately, my C++ seems to be too bad to implement this ... Please see the attached source files ... The errors I'm currently getting: In file included from bfs_map_test.cpp:14: bfs_distmap_as_color_map.hpp:42: error: ISO C++ forbids declaration of `graph_traits' with no type bfs_distmap_as_color_map.hpp:42: error: expected `;' before '<' token bfs_distmap_as_color_map.hpp:47: error: `key_type' has not been declared bfs_distmap_as_color_map.hpp:47: error: ISO C++ forbids declaration of `key' with no type bfs_distmap_as_color_map.hpp:62: error: `ColorValue MapAsColorMap::get' is not a static member of `class MapAsColorMap' bfs_distmap_as_color_map.hpp:62: error: template definition of non-template `ColorValue MapAsColorMap::get' bfs_distmap_as_color_map.hpp:62: error: `key_type' was not declared in this scope bfs_distmap_as_color_map.hpp:63: error: expected `;' before '{' token bfs_distmap_as_color_map.hpp:70: error: `key_type' has not been declared bfs_distmap_as_color_map.hpp:71: error: ISO C++ forbids declaration of `key' with no type bfs_distmap_as_color_map.hpp: In instantiation of `MapAsColorMap': bfs_map_test.cpp:58: instantiated from here bfs_distmap_as_color_map.hpp:49: error: `size_t[]' is not a class, struct, or union type bfs_distmap_as_color_map.hpp:58: error: `size_t[]' is not a class, struct, or union type bfs_map_test.cpp: In function `int main(int, char**)': bfs_map_test.cpp:58: error: no matching function for call to `MapAsColorMap::MapAsColorMap(size_t[5], int)' bfs_distmap_as_color_map.hpp:40: note: candidates are: MapAsColorMap::MapAsColorMap(const MapAsColorMap&) bfs_map_test.cpp:71: error: `copy_graph' undeclared (first use this function) bfs_map_test.cpp:71: error: (Each undeclared identifier is reported only once for each function it appears in.) bfs_map_test.cpp:88: error: `print_parent' undeclared (first use this function) bfs_map_test.cpp:88: error: expected primary-expression before '>' token bfs_map_test.cpp:91: error: expected `}' at end of input g++34 -c -o bfs_map_test.o -g -Wall -Wno-deprecated -pipe -O -I. -I/home/jmueller/software-gcc34/boost/include/boost-1_33_1 -I/sw/linux/LEDA/LEDA-5.0.1/include -I/sw/linux/LEDA/LEDA-5.0.1/incl -I/sw/linux/LEDA/LEDA-5.0.1/incl_old bfs_map_test.cpp Could someone point out the most stupid bugs? Thanks a lot in advance ...