completing-read-multiple is an autoloaded compiled Lisp function in `
(completing-read-multiple PROMPT TABLE &optional PREDICATE REQUIRE-MATCH INITIAL-INPUT HIST DEF INHERIT-INPUT-METHOD)
Read multiple strings in the minibuffer, with completion.
The arguments are the same as those of `completing-read'.
Input multiple strings by separating each one with a string that
matches the regexp `crm-separator'. For example, if the separator
regexp is ",", entering "alice,bob,eve" specifies the strings
"alice", "bob", and "eve".
We refer to contiguous strings of non-separator-characters as
"elements". In this example there are three elements.
Completion is available on a per-element basis. For example, if the
contents of the minibuffer are "alice,bob,eve" and point is between
"l" and "i", pressing TAB operates on the element "alice".
This function returns a list of the strings that were read,
with empty strings removed.