I am using SBCL and trying to pass a pointer to a c-struct to a CFFI routine.  The difficulty I am having is in formulating the function call correctly.  I have tried 'define-alien-routine' but was getting nowhere.  So now I am using cffi:foreign-funcall directly. Here is the call:

(cffi:foreign-funcall     "v4lconvert_convert"     :POINTER convert-info     :POINTER *camera-format*     :POINTER *display-format*     :POINTER raw-image     :INT *local-length*     :POINTER pixdata     :INT pixbuf-size     :INT)

It is the pointers to the two '-format' items that are causing the trouble I think.  Both of them were defined using defcstruct.

But the error message I get is complaining about the expansion of the foreign-funcall macro and makes no sense at all to me.  Can somebody help me interpret this?

;     (CFFI:FOREIGN-FUNCALL "v4lconvert_convert" ;        :POINTER ENCOMM.GUI::CONVERT-INFO ;        :POINTER ENCOMM.GUI::*CAMERA-FORMAT* :POINTER ;        ENCOMM.GUI::*DISPLAY-FORMAT* :POINTER ;        ENCOMM.GUI::RAW-IMAGE :INT ENCOMM.GUI::*LOCAL-LENGTH* ;                           ...) ; --> LET LET LET LET LET LET LET CFFI-SYS:%FOREIGN-FUNCALL ; --> CFFI-SYS::%%FOREIGN-FUNCALL ALIEN-FUNCALL ; --> SB-ALIEN-INTERNALS:INVOKE-WITH-SAVED-FP-AND-PC LAMBDA FUNCTION ; --> SB-ALIEN-INTERNALS:NATURALIZE LET LET LET LET LET LET LET ; --> SB-ALIEN-INTERNALS:MAYBE-WITH-PINNED-OBJECTS PROGN SB-C:%ALIEN-FUNCALL ; ==> ;   (SB-ALIEN-INTERNALS:DEPORT #:G77 ; '#<SB-ALIEN::ALIEN-SYSTEM-AREA-POINTER-TYPE SB-SYS:SYSTEM-AREA-POINTER>) ; ; caught WARNING: ;   Derived type of #:G77 is ;     (VALUES (ALIEN (* T)) &OPTIONAL), ;   conflicting with its asserted type ;     SB-SYS:SYSTEM-AREA-POINTER. ;   See also: ;     The SBCL Manual, Node "Handling of Types"