Hi, I don't know if anyone has tested CFFI on an X86-64 CLISP, but the following tests crash with an unexpected segfault: DEREF.ARRAY-OF-AGGREGATES STRUCT.ALIGNMENT.1 STRUCT.ALIGNMENT.2 STRUCT.ALIGNMENT.3 STRUCT.ALIGNMENT.4 STRUCT.ALIGNMENT.5 STRUCT.ALIGNMENT.6 STRUCT.ALIGNMENT.7 STRUCT.NESTED-SETF I'll see if I can figure out what's going on here, but so far I haven't found anything yet. James