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From: mitchalsup@aol.com (MitchAlsup1)
Newsgroups: comp.arch
Subject: Re: Segments
Date: Wed, 22 Jan 2025 22:25:33 +0000
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On Wed, 22 Jan 2025 20:00:30 +0000, Scott Lurndal wrote:

> mitchalsup@aol.com (MitchAlsup1) writes:
>>On Wed, 22 Jan 2025 14:58:04 +0000, Scott Lurndal wrote:
>>>(MitchAlsup1)
>
>>>>On a Linux machine, you can find the last envp[*] entry and subtract
>>>>SP from it.
>>>
>>> I would discourage programmers from relying on that for any reason
>>> whatsoever.   The aux vectors are pushed before the envp entries.
>>
>>This brings into question what is "on" the stack ?? to be included
>>in the measurement of stack size.
>>
>>Only user data ??
>>Data that is present when control arrives ??
>>Could <equivalent> CRT0 store SP at arrival ??
>>
>>I think we have an illdefined measurement !!
>
> Everything between the base address of the stack
> and the limit address of the stack.  The kernel exec(2)
> family system calls will allocate the initial
> stack region (with guard pages to handle extension)
> and populate it with the AUX, ENVP and ARG vectors
> before invoking the CRT in usermode.

So, how does one find the base (highest address on the stack) ??
in a way that works on every system capable of running C-code ??