An update on a closed issue #10847 - zlib-ng

[userdocs]

@xavier2k6 since this was your request this might be of interest to you. It's not request but an update based on the projects advancement since the issue was closed.

I stumbled across this closed issue by chance when dealing with some QT6 related build issues and I just wanted to try it out since they have released multiple stable releases since that point.

https://github.com/zlib-ng/zlib-ng/releases/tag/2.0.5

I have used it with api combability mode and it builds with no special requirements.

ZLIB_COMPAT=ON	--zlib-compat	Compile with zlib compatible API	Defaults to OFF

This might be an interesting option if QT6 builds become more important.

[FranciscoPombal]

Is there any advantage to using zlib-ng over zlib? IIRC qBittorrent doesn't make use of zlib very often, so I doubt there is any use case where it becomes the performance bottleneck.

Furthermore, it seems that some of zlib-ng's potential better performance would come from the use of CPU intrinsics, but we would not be able to make use of them in official builds, otherwise we would raise the minimum requirements way above what many systems are capable of (e.g. I expect there are still many people using machines without AVX2).

[userdocs]

I don't know. As I also don't know why qbittorrent needs zlib as a separate library to the one qtbase builds internally?

It was just an update to that issue as it appears the project has come some way since then and I can show it builds successfully.

I will use this in my project as I want to avoid the gnu website as much as possible for being unstable compared to github for pulling source files.

[xavier2k6]

Well, the maintainer & another team member were against using it at the time or to even use zstd as another alternative replacement.

Have you tried to build with zstd too?

I don't know how we could practically test these two as alternatives for pros & cons etc.

(we would have to fully understand where it's applied)

[userdocs]

I have not tried zstd as I do not know how to build that with qbittorrent as a replacement for zlib.

What I do know I that both qt5 and qt6 have support for linking it at qtbase build time

Again, what I don't know is if something linked into qtcore/qtnetwork needs to be linked again into qbittorrent as a separate dependency. zlib/zstd are both options to build into qtbase when building from source.

Since it appears really an issue of what can be done if building with QT6 since we might not see that in official repos for a long time so QT6 builds may be using non platform deps.

https://packages.debian.org/experimental/qtbase5-dev