Re: [Caml-list] Cash broken?

[Bruno.Verlyck@inria.fr]

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   Date: Thu, 27 May 2004 14:38:23 -0500
   From: John Goerzen <jgoerzen@complete.org>

Hi John,
   I tried this example straight from the docs:
    $ cashtop
	    Objective Caml version 3.07+2
	    Camlp4 Parsing version 3.07+2
    # open Cash;;
    # run_with_strings (fun () -> exec_path "ls" []);;
    Exception: Sys_error "Bad file descriptor".
    # Exception: Sys_error "Bad file descriptor".
   I can't make any of the run_with_* that I've tried work, whether in
   my programs or with cashtop.

   Ideas?  (Cash 0.20)
Not a lot with so little info (of course it works here).  Would you
mind sending me more OS details ?  A backtrace would be very useful,
and/or the result of trace/truss/strace -f ?

That said, what comes to mind is that the behavior of close_{in,out}
has changed in Pervasives over the last versions of Caml.  I wrote
some (too many) lines of code to make Cash.close_{in,out} work anyway.
I see in the CVS log that there was a change related to that, some
time after 3.07 (see the attached patch).  You could try it, or even
try the entire CVS version of Cash.

Bruno.

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Index: io_3_2.ml
===================================================================
RCS file: /net/pauillac/caml/repository/cash/io_3_2.ml,v
retrieving revision 1.47
retrieving revision 1.48
diff -c -a -r1.47 -r1.48
*** io_3_2.ml	2002/08/05 17:07:37	1.47
--- io_3_2.ml	2002/12/05 17:37:52	1.48
***************
*** 116,126 ****
        Some fd ->
          let res = low_close_fd fd in  (* low_close_fd will tell it. *)
          do {
!           close_any any_chan; (* Never raise exception in the current implementation. *)
            res
          } ]
    in
    (fun ichan -> close (anychan_of_ichan ichan),
     fun ochan -> do { flush ochan; close (anychan_of_ochan ochan) })
  ;
  
--- 116,129 ----
        Some fd ->
          let res = low_close_fd fd in  (* low_close_fd will tell it. *)
          do {
!           (* Used to raise no exception, but this varies between implementations... *)
!           try close_any any_chan with [ Sys_error "Bad file descriptor" -> () ];
            res
          } ]
    in
    (fun ichan -> close (anychan_of_ichan ichan),
+    (* Current religion says: flush do nothing on a closed channel. *)
+    (* Current implication is: if an unflushed channel's fd is closed, it's an error. *)
     fun ochan -> do { flush ochan; close (anychan_of_ochan ochan) })
  ;