peruse_crossref (pcref) should report inadequate access to selected .crossref seg/MSF

[Gary Dixon]

User of peruse_crossref (pcref) tool might get very confused from data displayed when that tool finds a selected (or the default) crossref data segment/MSF, but the user lacks access to it. Instead of reporting a sensible error, the tool ignores any lack-of-access error and begins
searching for cross reference entries matching the input arguments. This ends of display a message about running of end of stack frame.

pcref update_handler_

Error:  out_of_bounds at >user_dir_dir>Multics>GDixon>work>pcref_oob>peruse_crossref$pcref|3435 (line 671)
referencing stack_4|777770 (in process dir)
Attempt to reference beyond end of stack.
r 11:01 0.061 0 level 2

ts -bf
out_of_bounds condition:
234|4320    peruse_crossref$pcref|3435  (line 671)
234|3360    command_processor_$command_processor_|2101 (bound_multics_bce_|2101)
234|2700    abbrev$abbrev_processor|6105 (bound_command_loop_|14103)
234|2400    listen_$listen_|554 (bound_command_loop_|34522)
234|2000    initialize_process_$initialize_process_|704 (bound_process_init_|704)
r 11:02 0.132 0 level 2

pb
Condition out_of_bounds raised at line 671 of locate_line (level 8).
sk
 14          command_processor_
 13          abbrev_processor
 12          release_stack
 11          unclaimed_signal
 10          wall
  9          any_other.2
  8          locate_line (line 671)                        out_of_bounds
  7          find_line (line 819)
  6          print_matches (line 279)
  5          peruse_crossref (line 235)
  4          command_processor_
  3          abbrev_processor
  2          listen_
  1          initialize_process_

The command should verify that it is sufficient access to search the
cross reference data base, and report missing or inaccessible data
base issues to the user.