Cross-Platform Lan Connection


We’ve developed an application that allows architectural configurations from a mobile device (with a mobile build of an Unreal app) to a PC connected in a local network (which has the same build but with full quality assets for VR). While all of this works like a charm from Android to Windows, iOS does not seem to allow hosting nor joining any servers. I’ve read a lot of posts with a plethora of different solutions to wildly varying problems but none of them seem to change anything.

The precise issue seems to be that the OnlineSubSystem is uninitialized so CreateSession fails immediately after being called. The project builds fine and runs on the latest iPad Pro. The project is a C++ project mixed with blueprints and builds without problems on the promoted branch of UE4. The specific join/create logic is in a GameInstance blueprint and worked on any other platform tested (Android 32/64 bit to Windows 64 bit).

Between this and a lot of other iOS specific issues, the horrendously locked Apple ecosystem and non-existent support, we’ve decided to drop iOS all together.

This is just a known bug that was resolved in 4.21. It also requires a specific configuration. The way to fix it can be found here:…subsystem.html

Given that once you have your configuration right UE is basically mobile agnostic you might as well try it out.

I’d love to say “everything is solved” but the problem still persists. Subsystem is still completely ignored on iOS.

Did you also explicitly follow the build.cs file changes in the post?

yes, I just dropped the advertising part because I don’t need those.

Try putting it back in, the entire subsystem may work as a whole unit.

Nope, no luck there either.
I just find it very strange that other platforms require no setup at all for lan (online they do) while iOS seems to be the odd one out.
Having read almost all post related to iOS and LAN, I seem to be one of many having this problem, yet not a single post has been followed up by an Unreal Staff Member :frowning:

Yeah I don’t understand it either, and it’s all highly specific stuff too. I suspect it’s just a quirk of how Apple requires dylibs to be loaded.

Anyway, thanks for your help! If I’ll figure out the problem I’ll update this thread with a “nevermind, I found it” (jk)!