I received a report of an error when a function is called from lispbuilder-sdl-mixer on the Mac in both SBCL and CCL.

I think the problem is that CFFI does not allow memory to be freed if that memory has not also been allocated using CFFI.

In my code below, a new 'sdl-version' struct is returned by (sdl-mixer-cffi::linked-version). The error seems to occur when I try to free the struct at the end of the function using foreign-free.

 

(defun linked-version ()

    "Returns the version number of the SDL_mixer dynamic library in use as #\(`MAJOR` `MINOR` `PATCH`\)."

  (let ((sdl-version (sdl-mixer-cffi::linked-version))

(version nil))

    (cffi:with-foreign-slots ((sdl-cffi::major sdl-cffi::minor sdl-cffi::patch) sdl-version sdl-cffi::sdl-version)

      (setf version (vector sdl-cffi::major sdl-cffi::minor sdl-cffi::patch)))

    (cffi:foreign-free sdl-version)

    version))

Can I get around this somehow?

-Luke