Enable/Disable Steam Overlay

Is there any way to know if SteamOverlay is enabled or not?

And if so, what functions to use to activate and deactivate? How can I call them from my PlayerController.cpp?
What header files I need?

Thx a lot.

No you cannot disable the steam overlay at runtime (at least not without some dubious hacks). Valve tends to want to keep a consistent experience with the steam overlay between games. You can however request that its disabled globally on the steamworks forums - Steam Community :: Error

Perhaps I have not expressed well, sorry.

What I’m saying is if I can use a UMG-button to open/show SteamOverlay (in-game) instead of using Shift+TAB.

Thx.

any suggestions?

There is no ability to do this exposed by the OSS as far as I’m aware.

To do this you will have to write some C++ code to call SteamFriends()->ActivateGameOverlay(), although that is really meant for showing specific sub-screens of the overlay (friends/community/invite/etc), I’m not sure you can just open the overlay “vanilla”.