Abstract
As provided by Franz, Inc., the foreign function interface of Allegro Common Lisp has a number of limitations. This paper describes extensions to the interface that facilitate the inclusion of C and Fortran code into Common Lisp systems. In particular, these extensions make it easy to utilize libraries of numerical subroutines (such as those from Numerical Recipes in C) from within ACL, including those routines that take functions as arguments. A mechanism for creating Lisp-like dynamic runtime ``closures'' for C routines is also described.