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From: "Smarasderagd" <smarry@vex.net>
To: david_luyer@pacific.net.au, tjg@star.le.ac.uk
Cc: rc@hawkwind.utcs.toronto.edu
Subject: Re: building rc on QNX4
Date: Tue, 9 May 2000 00:34:20 -0400	[thread overview]
Message-ID: <20000509043420.2856.qmail@pantransit.reptiles.org> (raw)

David Luyer <david_luyer@pacific.net.au> writes:
>Basically some OS's (Digital Unix for one I think) have C libraries which
>choke horribly if the size of the command line + environment array is greater 
>than a certain value, and if you have a number of complex functions in your 
>shell this value (64k?) can be a pain.

In some cases this limit is enforced by the operating system; execve() chokes
on Linux if the arguments plus environment exceed (I think) 128K.

>Anyway - basically - I think it might be more useful to extend whatis such
>that it can be used to implement easily a facility to run a command without 
>any environment variables, rather than to actually implement that facility 
>internally.

If you don't need to export anything but non-array variables, the "-i"
or "-" option to "env" does what you want.  For the other cases:

You could have a whatis option (or a gnarly function that understands
enough rc syntax not to be fooled by newlines in quoted strings) that
spews null assignments / definitions for everything, and then eval the
result filtered for the things you want to preserve, but eeuugh.  If a
function is that big it won't be much slower if it's a script instead.


             reply	other threads:[~2000-05-09 22:54 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2000-05-09  4:34 Smarasderagd [this message]
2000-05-11 12:26 ` Gert-Jan Vons
  -- strict thread matches above, loose matches on Subject: below --
2000-05-08 15:23 Sam Roberts
2000-05-09  8:25 ` Carlo Strozzi
2000-05-08 15:15 Smarasderagd
2000-05-09  8:22 ` Carlo Strozzi
2000-05-08 10:19 Bengt Kleberg
2000-05-06 21:47 Byron Rakitzis
2000-05-04 13:46 Sam Roberts
2000-05-04  8:45 Byron Rakitzis
2000-05-06 10:28 ` Carlo Strozzi
2000-05-07 17:46   ` Paul Haahr
2000-05-08  8:01     ` Carlo Strozzi
2000-05-06 16:35 ` Jeremy Fitzhardinge
     [not found] <sroberts@uniserve.com>
2000-04-26 15:02 ` Sam Roberts
2000-04-27 16:56   ` Scott Schwartz
2000-04-27 20:41     ` Sam Roberts
2000-04-27 17:39   ` Carlo Strozzi
2000-05-02 14:41     ` Tim Goodwin
2000-05-04 15:18       ` Carlo Strozzi
2000-05-08  8:29         ` Tim Goodwin
2000-05-08  8:58           ` Chris Siebenmann
2000-05-08  9:15             ` Tim Goodwin
2000-05-08 23:25               ` Stephen Tell
2000-05-08 11:50           ` David Luyer
2000-05-08 13:28           ` Carlo Strozzi

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