Re: lynx-dev z (was Re: Timeout parameter?)

[Bela Lubkin]

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<