[Info-vax] Linking problem with multiply defined symbols, how to resolve?

[Stephen Hoffman]

On 2022-09-28 07:33:58 +0000, Richard Levitte said:

> I have this problem, that I want to build an app or a shareable image, 
> which is linked with another shared library, but which also implements 
> its own variant of symbols that are defined in that other shared 
> library.
> 
> This is intentional.  It works absolutely fine to do this on the Unixen 
> I've access to, as well as on Windows...  but VMS fails me.

It's not so reliable on various Unix systems; the results can entail 
indeterminate behavior even on some Unix systems, based on an error 
message I've met.

On OpenVMS, I have a tool Shimmer, which creates a new shareable image 
from an existing shareable image, and that allows interception of 
selected (or all) calls in the shareable image. I open-sourced this 
tool a while back, and probably still have a copy of it around. If 
you're interested in this interception, let me know and I'll poke 
around for a copy.

Otherwise, you're going to need to have some better hygiene around your 
symbols, which usually means some combination of building shareable 
images and using selective search qualifier, or maybe dynamic 
activation of the shareable image you want with the symbol you want at 
run-time using lib$find_image_symbol, this if linker clusters mentioned 
earlier don't get you where you need.




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