On Mon Sep 22, 2025 at 9:46 AM CEST, Massimo Nocentini via Chicken-users wrote:
>
> I have a progress using foreign-primitive for allocating objects.
>
> On the contrary, given the following definitions:
>
> (defineparse(foreign-primitivescheme-object(((constc-string) filename)
> (scheme-objectl))
> "P(C_k, filename, l);"))
>
> where function P is defined in a companion cpp file and reads as follows:
> C_wordc(C_wordC_k, C_wordl)
> {
> if(l==C_SCHEME_END_OF_LIST)
> {
> C_return(C_SCHEME_END_OF_LIST);
> }
> C_wordcdr=c(C_k, C_i_cdr(l));
> C_word*ptr=C_alloc(C_SIZEOF_PAIR);
> C_wordres=C_a_pair(&ptr, C_i_car(l), cdr);
> C_return(res);
> }
> externvoidP(C_wordC_k, constchar*filename, C_wordl)
> {
> C_kontinue(C_k, c(C_k, l));
> }
> My goal here is to just walk through the given list l and allocate fresh
> pairs for it. When I try:
> (parse "something.json" '(1 2 3))
>
> I still get:
>
> [...]
>
> What I'm doing wrong?
This can't work, as C_alloc allocates on the stack and C_return
in the function "c" will pop any created data again. C_return is
only valid _inside_ the foreign-primitive body.
cheers,
felix
