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; I want a function to be able to return a struct-by-val like this:

(foreign-lambda (struct "line") "foo" )

; My wrapper does this: 
; Allocate struct on stack and continue with continuation, returning address

(foreign-lambda* (c-pointer (struct "line")) () "struct line _tmp=foo();C_return(&_tmp);")

; When I run this once, twice, 10 times, it works all right.
; When I run it 100 times, the values become corrupted, as if something 
; gets eaten by chicken's GC. 

; What am I doing wrong?

; So I realized I needed to do foreign-primitive and use C_alloc (according to sjamaan and the docs).
; But my struct is still not stored in a safe place:

; my c-code looks like this:
;struct line foo2 () {
;  struct line l;
;  l.origin.tag = 11;
;  l.origin.x = 12;
;  l.origin.y = 13;
;
;  l.direction.tag = 14;
;  l.direction.x = 15;
;  l.direction.y = 16;
;  return l;
;}


(define make-line
  (foreign-primitive
   (c-pointer (struct "line"))
   ()
   "struct line *_tmp=(struct line*)C_alloc(sizeof(struct line));
*_tmp=foo2();
return(_tmp);"))

; I tried C_return with same results.
; C_malloc seems to work, however!