Thanks alot Martin ...that worked like a charm! =)
On Friday, October 25, 2013 4:20 AM, Martin Simmons <mar...@lispworks.com>
wrote:
>>>>> On Thu, 24 Oct 2013 17:30:49 -0700 (PDT), Joeish W said:
>
>>
>> here is the defcfun and deffun combo
>>
>> ;; void cvSplit(const CvArr* src, CvArr* dst0, CvArr* dst1, CvArr* dst2,
>> CvArr* dst3)
>> ;; Note: I had to use "CV-MERGE" instead of "MERGE" for the Common Lisp name
>> of CV-MERGE so I named this
>> ;; function CV-SPLIT so they would match.
>> (cffi:defcfun ("cvSplit" %split) :void
>> (src cv-arr)
>> (dest-0 cv-arr)
>> (dest-1 cv-arr)
>> (dest-2 cv-arr)
>> (dest-3 cv-arr))
>>
>> (defun cv-split (src dest-0 &optional (dest-1 (cffi:null-pointer)) (dest-2
>> (cffi:null-pointer)) (dest-3 (cffi:null-pointer)))
>> "Divides a multi-channel array into several single-channel arrays."
>> (%split src dest-0 dest-1 dest-2 dest-3))
>>
>>
>> it works as expected ...no errors at all
>>
>> my attempt at a macro(new to macros) below works in one piece of code when
>> the defun it is in is evaluated at the repl then ran at the repl
>>
>>
>> ;; #define cvCvtPixToPlane cvSplit
>> (defmacro cvt-pix-to-plane (src dest-0 &optional (dest-1
>> (cffi:null-pointer))
>> (dest-2 (cffi:null-pointer)) (dest-3 (cffi:null-pointer)))
>> "Macro for CV-SPLIT"
>> `(cv-split ,src ,dest-0 ,dest-1 ,dest-2 ,dest-3))
>>
>> but in the same code when used the exact same way inside emacs (using
>> slime/sbcl on ubuntu saucy) when it is placed inside a newly opened file
>> (.lisp) or even my well used test.lisp file and ran with
>> slime-compile-and-load-file i get
>>
>>
>>
>> error:
>> Objects of type SB-SYS:SYSTEM-AREA-POINTER can't be dumped into fasl
>> files.
>> --> CL-OPENCV::CV-SPLIT
>> ==>
>> #.(SB-SYS:INT-SAP #X00000000)
>>
>> can you help me figure out the issue and write macros with null-pointers
>> correctly
>
>This is a common gotcha with &optional/&key in macros: the default value is
>evaluated during macroexpansion, so in general it should be a form.
>
>I.e. you need `(cffi:null-pointer) instead of (cffi:null-pointer).
>
>__Martin
>
>
>
>
>
