tags-loop-scan

tags-loop-scan is a variable defined in `etags.el'.
Its value is

(user-error "%s"
	    (substitute-command-keys "No \\[tags-search] or \\[tags-query-replace] in progress"))

Documentation:
Form for `tags-loop-continue' to eval to scan one file.
If it returns non-nil, this file needs processing by evalling
`tags-loop-operate'. Otherwise, move on to the next file.