sizeof-fobject

Arguments: name-or-ftype

Return the size of an object of the given foreign type (the argument can be a name of a foreign type or an ftype object). The size only includes the data bytes and not any overhead bytes needed by lisp. name-or-ftype can be an actual foreign object which has a defined type so long as its allocation type is :foreign or :foreign-static-gc. The allocation type is defined when the object is created by, say, allocate-fobject. Objects of allocation type :lisp have their own lisp types, and thus do not imply a foreign-type; and objects of :c allocation are just integers, and thus again do not imply a foreign-type.

Example

cl-user(1): (ff:def-foreign-type point (:struct (x :int) (y :int)))
#<foreign-functions::foreign-structure point>
cl-user(2): (setq obj (ff:allocate-fobject 'point :foreign-static-gc))
#<foreign object of class point>
cl-user(3): (ff:sizeof-fobject 'point)
8
cl-user(4): (ff:sizeof-fobject (ff:get-foreign-type 'point))
8
cl-user(5): (ff:sizeof-fobject obj)
8
cl-user(6): 

See ftype.htm for information on foreign types in Allegro CL and foreign-functions.htm for general information on foreign functions in Allegro CL.

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This page has had moderate revisions compared to the 6.2 page.
Created 2005.9.20.