Title says it all, here are my concerns.

1. I want a copyleft license, but not at the cost of having to reveal private code in a game project.
2. I mostly just want to create a game engine that can serve as a 'base' that other developers can build distros with that may target different languages, platforms, runtimes etc etc.

I will likely be building my app with GTK and some language bindings, but those are my main concerns. Otherwise, If companies have to release their code with my engine, I would switch to something more permissive like Apache 2.0 If anyone can give me an in depth answer for someone who wants to do exclusively open source, please let me know! Thank you very much ahead of time!

Edit 1: So just to be clear, I am looking at GPL/LGPL but if game developers have to release their source code for their game, I would like an alternative. I am mostly just concerned about the GPL 'share source code' clause with new projects that build off my soon to be work.

Title says it all, here are my concerns.

1. I want a copyleft license, but not at the cost of having to reveal private code in a game project.
2. I mostly just want to create a game engine that can serve as a 'base' that other developers can build distros with that may target different languages, platforms, runtimes etc etc.

I will likely be building my app with GTK and some language bindings, but those are my main concerns. Otherwise, If companies have to release their code with my engine, I would switch to something more permissive like Apache 2.0 If anyone can give me an in depth answer for someone who wants to do exclusively open source, please let me know! Thank you very much ahead of time!

Edit 1: So just to be clear, I am looking at GPL/LGPL but if game developers have to release their source code for their game, I would like an alternative. I am mostly just concerned about the GPL 'share source code' clause with new projects that build off my soon to be work.

Edit 2 (IMPORTANT!): I love all the answers here everyone and I learned a lot! I decided to split my project into two licenses, and instead go with the more 'permissive' MPLv2 and LGPLv3. While all the answers were a great resource, be sure to do your own research on licensing! A great bit of helpful resources I found during this mission.

MPL compatibility: https://www.fsf.org/blogs/licensing/mpl-2.0-release General License List: https://www.gnu.org/licenses/license-list.html

And of course, the MPL license itself: https://www.mozilla.org/en-US/MPL/2.0/FAQ/

As noted by the highlighted answer, none of us (including me) is a lawyer. Be skeptical but also inquisitive.

Thank you all so much!

Title says it all, here are my concerns.

1. I want a copyleft license, but not at the cost of having to reveal private code in a game project.
2. I mostly just want to create a game engine that can serve as a 'base' that other developers can build distros with that may target different languages, platforms, runtimes etc etc.

I will likely be building my app with GTK and some language bindings, but those are my main concerns. Otherwise, If companies have to release their code with my engine, I would switch to something more permissive like Apache 2.0 If anyone can give me an in depth answer for someone who wants to do exclusively open source, please let me know! Thank you very much ahead of time!

Title says it all, here are my concerns.

1. I want a copyleft license, but not at the cost of having to reveal private code in a game project.
2. I mostly just want to create a game engine that can serve as a 'base' that other developers can build distros with that may target different languages, platforms, runtimes etc etc.

I will likely be building my app with GTK and some language bindings, but those are my main concerns. Otherwise, If companies have to release their code with my engine, I would switch to something more permissive like Apache 2.0 If anyone can give me an in depth answer for someone who wants to do exclusively open source, please let me know! Thank you very much ahead of time!

Edit 1: So just to be clear, I am looking at GPL/LGPL but if game developers have to release their source code for their game, I would like an alternative. I am mostly just concerned about the GPL 'share source code' clause with new projects that build off my soon to be work.