(define-ftype in_addr
      (struct (s_addr in_addr_t)))
    
    ;; WARNING- here the size of sin_zero should be calculated on your machine as:
    
    #;(import (c-eval))
    #;(parameterize ([c-eval-includes '("stdio.h" "sys/socket.h" "netinet/in.h")])
    (c-eval-printf "%d" "sizeof(struct sockaddr_in) - sizeof (sa_family_t) - sizeof(in_port_t) - sizeof(in_addr_t)"))
    (c-eval-printf "%d" "sizeof(((struct sockaddr_in *) NULL)->sin_zero)"))
    ;; in my case  (a6le) -> 8
    
    (define-ftype sockaddr_in
      (struct
       (sin_family sa_family_t)
       (sin_port in_port_t)
       (sin_addr in_addr)