Can a single entt::observer track if a component is either added or updated?

[Net5F]

Hello! This answer might be obvious but I'm having trouble figuring it out.

Can a single entt::observer be used to track if a given component type is either added to an entity or updated? Or does this require 2 observers?

For context, I need to end up with a list of unique entities that had a given component type added or updated. If 2 observers are indeed required, is the best approach to sum their lists, sort, and remove duplicates?

[skypjack]

Uhm, out of my mind, it should be entt::collector.group<T>().update<T>(). Have you tried it already?

[Net5F]

Looks like that works, thank you!

[Net5F]

On MSVC everything works great, but GCC needed some help with parsing:

entt::collector.group<T>().template update<T>()

Unfortunately it also has a warning:

/.../Libraries/entt/src/entt/entity/registry.hpp:983:49: warning: parameter ‘entt’ set but not used [-Wunused-but-set-parameter]
  983 |     [[nodiscard]] bool any_of(const entity_type entt) const {
      |                               ~~~~~~~~~~~~~~~~~~^~~~

It would be nice if there was a way to get rid of the warning, but it isn't too big of a deal.

[skypjack]

Oh, good catch. The class invokes any_of and the latter also accepts an empty parameter pack.
In this case, entt isn't used actually. A [[maybe_unused]] is enough but it's not there in your version.
Adding it upstream though. Completely missed so far. Sorry.

[Net5F]

No worries! I appreciate you adding the fix, and also thanks for building all of this 😄 I'm wrapping up this work, then I'll be excited to share some of the cool stuff this library has allowed me to do.