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From: Ross Patterson <me AT rpatterson DOT net>
Subject:  Re: Cygwin Python/PIL TCL/TK fork rebase solution
Date:  Tue, 16 Jan 2007 10:09:50 -0800
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Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com> writes:

> On Tue, Jan 16, 2007 at 05:50:06PM +0000, Robin Walker wrote:
>>For this to be the problem it appears to be, I'm guessing that there must 
>>be some shortcoming in the Windows APIs in this area when compared with 
>>facilities available within other Posix-compliant OSs.
>
> It isn't a shortcoming at all.  Windows is perfectly within its rights
> to put DLLs whereever it wants.  Windows doesn't implement fork() so it
> doesn't have to worry about creating a new process whose addresss space
> is a carbon copy of another process.
>
>>How does Linux deal with the same issues of having libraries (or whatever 
>>are logically equivalent to DLLs) potentially linked at different bases in 
>>the two address spaces?
>
> fork() is part of the OS in Linux and the fork() function is absolutely
> intrinsic and necessary for anything on Linux or UNIX to work correctly.
> It doesn't have to deal with anything like this since a fork is in the
> low level of the OS, not in a library running in an application.

This has been an illuminating discussion and has given a lot more
detail to what I already understood about the rebase/fork issue.

I'd still like to understand how one chooses base address and offset
values for rebase, seeing as I was just shooting in the dark until
something said "OWW!"  :)

Anyone?

Ross


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