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Re: lynx-dev z (was Re: Timeout parameter?)
From: |
Bela Lubkin |
Subject: |
Re: lynx-dev z (was Re: Timeout parameter?) |
Date: |
Tue, 22 Dec 1998 15:25:01 -0800 |
Kari E. Hurtta wrote:
> Bela Lubkin:
(a long time ago)
> > brian j. pardy wrote:
> >
> > > IIRC, gethost[by]name() (whichever lynx uses, no source in front of me)
> > > blocks when looking up a hostname, making it impossible to interrupt it.
> > > That's why forking it away allows an interrupt.
> >
> > gethostbyname() comes from the BIND resolver library [dunno about under
> > Windows or VMS]. In older 4.8/4.9 versions of the library, there are
> > timeout parameters which can be modified. Unfortunately, they're in an
> > internal structure which isn't documented or intended to be exposed.
> > (I'm talking about struct __res_state _res, fields "retrans" and
> > "retry".) I don't know whether this situation has changed in the
> > current BIND 8.x versions.
>
> yes. Sendmail uses lot of code like:
>
> #if NAMED_BIND
> /* unless interactive, try twice, over a minute */
> if (OpMode == MD_DAEMON || OpMode == MD_SMTP)
> {
> _res.retrans = 30;
> _res.retry = 2;
> }
> #endif
>
> As far I know many have compiled sendmail with BIND 8.
That's inconclusive (to me, not knowing the sendmail build environment):
"NAMED_BIND" might be defined only for BIND 4.x, not 8.x.
> Lynx is of course availabe much more systems that BSD (or Open Source)
> Sendmail :-)
Right, and this is no longer relevant since Lynx is using fork() and
select() to control the duration of DNS lookups. We could conceivably
also, or alternatively, use BIND retrans/retry, but I don't see much
point in it.
>Bela<