# Objective
- Contributes to #15460
## Solution
- Added the following features:
- `std` (default)
- `bevy_tasks` (default)
- `downcast ` (default)
- `portable-atomic`
- `critical-section`
- `downcast` and `bevy_tasks` are now optional dependencies for
`bevy_app`.
## Testing
- CI
- Personal UEFI and Raspberry Pi Pico demo applications compile and run
against this branch
## Draft Release Notes
Bevy's application framework now supports `no_std` platforms.
Following up on `bevy_ecs` gaining `no_std` support, `bevy_app` extends
the functionality available on these targets to include the powerful
`App` and `Plugin` abstractions. With this, library authors now have the
option of making their plugins `no_std` compatible, or even offering
plugins specifically to improve Bevy on certain embedded platforms!
To start making a `no_std` compatible plugin, simply disable default
features when including `bevy_app`:
```toml
[dependencies]
bevy_app = { version = "0.16", default-features = false }
```
We encourage library authors to do this anyway, as it can also help with
compile times and binary size on all platforms.
Keep an eye out for future `no_std` updates as we continue to improve
the parity between `std` and `no_std`. We look forward to seeing what
kinds of applications are now possible with Bevy!
## Notes
- `downcast-rs` is optional as it isn't compatible with
`portable-atomic`. I will investigate making a PR upstream to add
support for this functionality, as it should be very straightforward.
- In line with the `bevy_ecs` no-std-ification, I've added documentation
to all features, and grouped them as well.
- ~~Creating this PR in draft while CI runs and so I can polish before
review.~~
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
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