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From: "Ozkan Sezer (sezeroz AT gmail DOT com) [via djgpp AT delorie DOT com]" <djgpp AT delorie DOT com>
Date: Fri, 16 Aug 2019 00:00:31 +0300
Message-ID: <CAA2C=vCoQth+AZc9FsEqX2A2STx9kVMvJ8moYHLzjgP=uc1cMQ@mail.gmail.com>
Subject: Re: [patch] fix empty environment handling
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On 8/11/19, Stas Sergeev (stsp2 AT yandex DOT ru) [via djgpp AT delorie DOT com]
<djgpp AT delorie DOT com> wrote:
> Hello.
>
> There are several djgpp-written shells in the
> wild, and they are troubled with the fact that
> djgpp does not handle the empty environment.
>
> Every DOS has its own way of presenting the
> empty environment:
> - FreeDOS presents it as "0xd 0x1 0x0 <argv0>"
> which is the worst possible representation.
> Fortunately they noticed that all shells crash,
> and added a work-around to set "PATH=."
> instead of keeping the env empty. No work-around
> is therefore needed on djgpp side.
> - fdpp (freedos-plus-plus) presents an empty
> env as "0x0 0x1 0x0 <argv0>". The attached
> patch handles this by moving the env-traversion
> loop condition check before the loop itself.
> - PC/MS-DOS presents an empty env as 0 in
> the PSP:2c. For that condition, the attached patch
> adds a check and the adequate error message.
> The only work-around is to use "set PATH=."
> in config.sys.
> - DR-DOS always puts 0 in PSP:2c, regardless
> of whether the env is empty or not. No easy
> work-around for that one, other than to run
> the djgpp-written shell via the native shell.
>
> Patch attached.

Has anyone reviewed and/or tested this?