Hello, What is the right way to create a 2D array to pass to a c-function that expects **arr? I tried: (defun make-matrix (lisp-mat) "Creates a two-dimensional c array, initializes with lisp matrix" (let* ((x-dim (array-dimension lisp-mat 0)) (y-dim (array-dimension lisp-mat 1)) (c-mat (foreign-alloc :pointer :count y-dim))) (dotimes (y y-dim) (let ((cur (foreign-alloc :double :count x-dim))) (setf (mem-aref c-mat :pointer y) cur) (dotimes (x x-dim) (setf (mem-aref cur :double y) (coerce (aref lisp-mat x y) 'double-float))))) c-mat)) To pass the argument z to the c-function: c_plmesh(PLFLT *x, PLFLT *y, PLFLT **z, PLINT nx, PLINT ny, PLINT opt); (PLFLT is of type double & PLINT is of type int) But some of the values appear to get mangled in transit. Thanks, -Hazen (CFFI 0.9.0, SBCL 0.9.9, OS-X 10.4)