1+++ 2title = "Redefining `message()`" 3weight = 50 4+++ 5 6You may remember that our custom `_file_io_error_domain` inherits from 7`outcome_e::posix_code::domain_type`, and thus does not have to 8implement the many pure virtual functions required by `outcome_e::status_code_domain`. 9 10What we do need to do is reimplement `_do_message()` to append the 11file and line information to the POSIX error description string 12returned by `outcome_e::posix_code::domain_type`. This causes 13the status code's `.message()` observer to return a string 14with the extra payload information represented in text. 15 16{{% snippet "experimental_status_code.cpp" "message" %}} 17 18