gnu_cxx::hash_map is behaving strangely

I am trying to find an element in a gnu_cxx::hash_map that is keyed by strings. The string I am searching is "\xofiller!fill!1_620200 " (thereis only 1 backslash at the beginning. The element is not found. So inside gdb I change the search key to "xofiller!fill!1_620200 " and the element is found but oddly the key of the pair found is the original on. "\xofiller!fill!1_620200 ". I am using std::equal_to which is really ==. I experimented and I can lose a few characters at the end as well. I am starting to suspect that GDB is misleading me. Is there something special about a backslash at the beginning? Thanks Danny