Needed to use the cscope tool
– required list of files
Couldn’t be bothered to RTFM. Should be header files be included in the cscope database?
– First example in  item (3) doesn’t help if both the ‘c’ and ‘h’ files are to be included.
– Second more complex example, last line gives clue.
– modified the regular expression in the option to: -name “*.[ch]”