[gambit-list] Creating a list of C structs and returning it to Scheme

Hi everyone,

Long time reader, first time writer. I want to create a list of C structs and return them to Scheme with the following code:

(c-declare #<<c-list-of-structs

typedef struct my_struct my_struct;     struct my_struct     {         int* data;     };

___SCMOBJ my_struct_free( void* p )     {         my_struct* s = (my_struct*)p;         if( !s )         {             printf( "list_struct_free: %i\n", *s->data );             free( s->data );             return ___FIX( ___NO_ERR );         }         return ___FIX( ___UNKNOWN_ERR );     }

// create a list of n my_structs     ___SCMOBJ create_list( int n )     {         ___SCMOBJ ___err = ___FIX( ___NO_ERR );         ___SCMOBJ list = ___NUL;         ___SCMOBJ new_list;         my_struct* ls;

while( n > 0 )         {             ls = malloc( sizeof( my_struct ) );             ls->data = malloc( sizeof ( int ) );             *ls->data = n;             ___SCMOBJ element = ___NUL;             ___err = ___STRUCT_to_SCMOBJ( ___PSTATE,                                           ls,                                           ___FAL,                                           my_struct_free,                                           &element,                                           0 );             new_list = ___EXT( ___make_pair ) ( ___PSTATE, element, list );             ___EXT( ___release_scmobj ) ( list );             ___EXT( ___release_scmobj ) ( element );             list = new_list;             --n;         }         return list;     }

c-list-of-structs )

;(c-define-type my-struct (struct "my_struct")) (c-define-type my-struct (struct "my_struct" 'my-struct "my_struct_free")) (c-define-type my-struct* (pointer my-struct))

(define create-list   (c-lambda (int)     scheme-object "create_list"))

(define square-my-struct!   (c-lambda (my-struct)     void "*___arg1.data *= *___arg1.data;"))

(define print-my-struct   (c-lambda (my-struct) void #<<c-print-my-struct

printf( "my_struct: %i\n", *___arg1.data );

c-print-my-struct ))

(define test-list (create-list 10)) (map print-my-struct test-list) (map square-my-struct! test-list) (map print-my-struct test-list)

While this kind of works, there's two problems here: One, how do I fix the tags for my foreign objects in the list so that they're displayed as my-struct, not foreign? Two, how do I make the GC call my release-function correctly for my_struct?  Any help is much appreciated. Background: I have a STM32 Nucleo board, I'd like the C code on it to be able to communicate with a Scheme program on my laptop.

Kind regards,

Georg