[Chicken-users] 'f_125' undeclared with (declare (block))

[.alyn.post.]

I'm getting an error message when I use |(declare (block))|.

Using the same code in my previous email about invalid forwarded
object (repeated here), I declare it as an egg like so (the only
change is wrapping it around a module):

<++> csc -s -j pwent pwent.so pwent-egg.scm
(module pwent
  (getpwent)

(import scheme)
(import chicken)
(import foreign)

(declare (block))

; a circular list (where we track the
; head and tail) with a dummy head.
;
(define (make-clist)
  (let ((head (list #f)))
    (cons head head)))

; O(1) list append.
;
(define (clist-append! d v)
  (let ((l (list v)))
    (set-cdr! (cdr d) l)
    (set-cdr! d l)))

; return proper list
;
(define (clist->list d)
  (cdr (car d)))

; allocate a scheme string available in C.
;
(define-external
  (_make_string (size_t n)) scheme-object
    (make-string n))

(declare (foreign-declare #<<EOF
#include <sys/types.h>
#include <string.h>
#include <pwd.h>
EOF
))

(define (getpwent)
  ; append! each pwent record to our record list.
  ;
  (define-external
    (_getpwent_cb (scheme-object clist)
                  (scheme-object user)
                  (scheme-object passwd)
                  (scheme-object uid)
                  (scheme-object gid)
                  (scheme-object home)
                  (scheme-object shell)) void
      (let ((pwent `((user   . ,user)
                     (passwd . ,passwd)
                     (uid    . ,uid)
                     (gid    . ,gid)
                     (home   . ,home)
                     (shell  . ,shell))))
        (clist-append! clist pwent)))

  ; retrieve the next pwent record and marshall it
  ; in to scheme.
  ;
  (define _getpwent
    (foreign-safe-lambda* bool ((scheme-object clist)) #<<EOF
    struct passwd *pw;
    C_word shell, dir, passwd, name;
    size_t n;

    pw = getpwent();

    if(!pw) {
      endpwent();
      C_return(0);
    }

    n = strlen(pw->pw_name);
    name = _make_string(n);
    C_memcpy(C_c_string(name), pw->pw_name, n);

    n = strlen(pw->pw_passwd);
    passwd = _make_string(n);
    C_memcpy(C_c_string(passwd), pw->pw_passwd, n);

    n = strlen(pw->pw_dir);
    dir = _make_string(n);
    C_memcpy(C_c_string(dir), pw->pw_dir, n);

    n = strlen(pw->pw_shell);
    shell = _make_string(n);
    C_memcpy(C_c_string(shell), pw->pw_shell, n);

    _getpwent_cb(clist,
                 name,
                 passwd,
                 C_fix(pw->pw_uid),
                 C_fix(pw->pw_gid),
                 dir,
                 shell);
    C_return(1);
EOF
))

  ; loop ever every entry in pwent and append
  ; it to our list.
  ;
  (let loop ((clist (make-clist)))
    (if (_getpwent clist)
        (loop clist)
        (clist->list clist)))))
<-->

With that |(declare (block))|, I get the following error message:

pwent.c: In function '_getpwent_cb':
pwent.c:107: error: 'f_125' undeclared (first use in this function)
pwent.c:107: error: (Each undeclared identifier is reported only once
pwent.c:107: error: for each function it appears in.)

Error: shell command terminated with non-zero exit status 256: gcc pwent.c -o 
pwent.o -c  -fno-strict-aliasing -DHAVE_CHICKEN_CONFIG_H -DC_ENABLE_PTABLES -Os 
-fomit-frame-pointer -fPIC -DPIC -DC_SHARED -I/usr/X11R6/include 
-I/usr/local/include

Removing |(declare (block))| allows compilation as normal.
Usefully, the egg version of this code does not exhibit the 
invalid forward object error and completes successfully:

  $ csi -n
  #;1> (use pwent)
  ; loading ./pwent.import.scm ...
  ; loading /usr/local/lib/chicken/6/chicken.import.scm ...
  ; loading /usr/local/lib/chicken/6/foreign.import.scm ...
  ; loading ./pwent.so ...
  #;2> (getpwent)
  (((user . "root") ...))

While it's certainly a blessing that my above code works when
compiled as an egg (though why it does so is a mystery to me),
what's going on with |(declare (block))| here?  I don't understand
the documentation on this declare option to know whether I'm doing
something wrong or whether this code cannot be compiled with that
declaration.

Thank you,

-a

$ csc -V
(c) 2008-2013, The Chicken Team
(c) 2000-2007, Felix L. Winkelmann
Version 4.8.0.5 (stability/4.8.0) (rev 5bd53ac)
openbsd-unix-gnu-x86 [ manyargs dload ptables ]
compiled 2013-10-03 on aeryn.xorinia.dim (Darwin)
-- 
my personal website: http://c0redump.org/