The g:list-t type specifier represents a C doubly linked list with elements of the GList structure. The g:list-t type specifier performs automatic conversion from a C list to a Lisp list. The elements of the list can be pointers, strings or GObjects.

(cffi:convert-to-foreign (list "a" "b" "c") '(g:list-t :string))
=> #.(SB-SYS:INT-SAP #X03B92220)
(cffi:convert-from-foreign * '(g:list-t :string))
=> ("a" "b" "c")