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[Caml-list] Unix subdaemon, channels, filedescriptors....
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Date: 2002-07-17 (16:05)
From: Bruno.Verlyck@i...
Subject: Re: [Caml-list] Unix subdaemon, channels, filedescriptors....
   Date: Wed, 17 Jul 2002 16:06:31 +0200
   From: Basile STARYNKEVITCH <>

   I would like to close all the filedescriptors after the fork.
This is what set_close_on_exec is for, except it's after the exec.
Is it enough ?  (You wrote `it fork and execs processes').

   Unfortunately, the caml_out_channels_list primitive (coded in C in
   ocaml/byterun/io.c), which is used in stdlib/ is not
   published in pervasives.mli, and there is no caml_in_channels_list

   May I suggest publishing this primitive in the future ocaml v3.05?
Do you mean: these two primitives ?

BTW, all this stuff was added to support Cash (now you know what is my
next suggestion :-).  Since flush_all was considered of general
interest, caml_out_channels_list was integrated to the main sources to
implement it.  Had flush_all not been added to Pervasives, it would
have stayed in the C part of Cash.  So to get caml_out_channels_list
right now, an external declaration is enough.  For
caml_in_channels_list, 20 lines of C will do (1).

   Also, Unix.open_process_in and related seems to forget closing the file
   descriptors in the child process, 
   How do I close (in Ocaml) every channel except stdin, stdout, stderr?
In the next version (and in the CVS sources), every channel opened by
Pervasives is marked by set_close_on_exec, so this problem should go


(1) At first sight, copy caml_out_channels_list, and replace
    if (channel->max == NULL) {
    if (channel->max != NULL && channel->fd >= 0) {
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