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nagisa / rust_libloading

Bindings around the platform's dynamic library loading primitives with greatly improved memory safety.
https://docs.rs/libloading
ISC License
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loading dylib from rust host program with libloading, recompiling dylib, reloading dylib does not see the new plugin version until the host fully restarts #108

Closed klebs6 closed 2 years ago

klebs6 commented 2 years ago

Greetings folks! I have been enjoying working with the library so far! I am encountering an unexpected behavioral error, though...

It is possible that there is some simple, obvious mistake in my setup and I will find it first thing in the morning!

I figured I would post here just in case there is somebody who might already know what to do.

I can add more detail after getting some sleep, but the basic gist is that I am writing a plugin (in rust) for a host (in rust), and am using the libloading library to handle the symbol loading etc at the interface.

Most everything seems to be working quite well -- the plugin loads on demand and the code executes as I expect it to.

However, when I need to make a change to the plugin and recompile it with cargo, reloading the dylib from the host does not seem to see the new changes. If I exit the host, relaunch the host, and load the plugin once more on demand, it picks up the new changes.

My first attempt at a solution was to manually call close on the libloading::Library after I am done using the plugin, before reloading it. That didn't seem to work, though it is possible I made a mistake.

I have not had a chance to inspect the situation more deeply, but am also not quite sure yet where to start...

I think getting some sleep might help! I am off to take care of that now! 😁😴 Thanks in advance for any help!

klebs6 commented 2 years ago

ah, looks to be the same/similar issue to #59 will try the solution there in the morning! closing for now!

nagisa commented 2 years ago

Yeah, most likely reason is that the old library remains loaded for one reason or another and trying to load a new one just increments a reference count for the old one rather than loading a new one.

This can happen for various reasons depending on the platform being targeted so unfortunately there isn’t really a nice straightforward cross-platform solution to this.