The g:slist-t type specifier performs automatic conversion from a C GSList instance to a Lisp list. The elements of the list can be pointers, strings or GObjects.

The gtk:builder-objects and gtk:size-group-widgets functions are examples for the use of the g:slist-t type specifier in the Lisp implementation. These functions return a list of g:object instances which are converted from C GSList instances.

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