Subject: Re: dlopen'ing a plugin that calls functions in the parent...
To: None <>
From: Oleg Polianski <>
List: netbsd-users
Date: 09/10/2001 19:27:01
Jason R Thorpe <> writes:

Hi there

 It could be somewhat very similar but looks slightly different (another
 symnum) and I still don't understand what exactly could be wrong. I'm trying
 to preload shared object which simply overrides some entry points in
 `' and does rendering properly (support for anti-aliasing); it
 tries to access some code from `' (which is part of locally built
 XFree86 4.1.0) as well. But when I start the program (any gtk-based program
 which uses font widgets), I get the following:

simoom p5 /opt/tmp/gdkxft-1.0 10211% LD_PRELOAD=/usr/local/lib/ gfontsel
/usr/local/lib/ Undefined PLT symbol "XftFontOpenXlfd" (reloc type = 7, symnum = 67)

 I recompiled both, `libXft' and `gdkxft' with `--export-dynamic' but still
 have no success. I went through the code, it doesn't look strange - only
 dlopen/dlsym/indirect call sequences, i.e. it doesn't have any callbacks and
 so on. Still wondering, what could be wrong, any ideas are greatly

> On Wed, Sep 05, 2001 at 09:55:06PM +0100, Jasper Wallace wrote:
>  > I'm trying to get the wirless plugin[1] for gkrellm[2] to work under
>  > NetBSD 1.5.2.
>  > 
>  > After digging around with gdb the call to dlopen() on the plugin fails with
>  > (as reported dy dlerror()):
>  > 
>  > Error: /usr/home/jasper/.gkrellm/plugins/ Undefined PLT symbol
>  > "gkrellm_draw_decal_text" (reloc type = 7, symnum = 31)
>  > 
>  > gkrellm_draw_decal_text is a function in gkrellm (and gkrellm is NOT
>  > striped).
> gkrellm needs to be linked with the -E (--export-dyanmic) option.  That
> should fix your problem.
> Any program which opens a shared object that needs to call back into
> the parent needs this option.  I guess maybe it's the default on Linux,
> or something, because lots of programs fail to include it in their
> Makefiles.
> -- 
>         -- Jason R. Thorpe <>

        -- Oleg Polianski <>