The author made this library to work with the Wayland compositor protocol, whose protocol encourages passing shm objects between the server and clients to handle stuff like surface buffers, clipboard etc. To make it feel more like Common Lisp, I transformed shm_open(3)'s API to feel much more like cl:open, and with-open-shm/with-mmap/with-mmapped-ship macros to feel like with-open-file.
posix-shm
posix-shm provides Common Lisp bindings to the POSIX shared memory API.