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From: "Ozkan Sezer (sezeroz AT gmail DOT com) [via djgpp AT delorie DOT com]" <djgpp AT delorie DOT com>
Date: Thu, 16 Feb 2023 14:10:14 +0300
Message-ID: <CAA2C=vASQ0KY_jA05tUWpRHTocGtDKgn=KAU00JOezmbRu827Q@mail.gmail.com>
Subject: Re: dxe: page fault when derefencing an exported pointer variable
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On 2/16/23, Ozkan Sezer <sezeroz AT gmail DOT com> wrote:
> dxe: page fault when derefencing an exported pointer variable
>
> The project in question is libmikmod along with its mikmod player:
> https://github.com/sezero/mikmod
>
> The libmikmod library exports many functions and variables, only
> one of those variables is a pointer:
> https://github.com/sezero/mikmod/blob/master/libmikmod/playercode/mdriver.c#L51
>
> The 'normal' vars don't seem to have a problem, but dereferencing
> that particular pointer results in a page fault:
> https://github.com/sezero/mikmod/blob/master/mikmod/src/display.c#L338-L339
>
> At time of dereferencing the pointer is not actually NULL, because
> if I write an accessor returning that pointer and export and use it
> then things work. (Yes, the library and its api are a mess, I know)
>
> Using dxe3gen from CVS -- can give instructions to reproduce / test
> if requested.
>
> Anyone has an insight, please?

I forgot to mention that:
- I link to the DXE module using an import library, not manually.
- There are no issues if I link the exe statically to libmikmod.

Need help with this - any insight would be appreciated.