New tiny example of FFI

examples/ffi/ecl.lsp

@@ -0,0 +1,16 @@
+#|
+Build and load this module with (compile-file "ecl.lsp" :load t)
+|#
+;;
+;; With this other statement, we import the C function sin(), which
+;; operates on IEEE doubles. Notice that we include the C header to
+;; get the full declaration.
+;;
+(defun c-sin (x)
+  (ffi:clines "#include <math.h>")
+  (ffi:c-inline (x) (:double) :double "sin(#0)" :one-liner t))
+;;
+;; We now use this function and compare with the lisp version.
+;;
+(format t "~%Lisp sin:~t~d~%C sin:~t~d~%Difference:~t~d"
+	(sin 1.0d0) (c-sin 1.0d0) (- (sin 1.0d0) (c-sin 1.0d0)))