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+# Singletons
+
+The `app` attribute is aware of [`owned-singleton`] crate and its [`Singleton`]
+attribute. When this attribute is applied to one of the resources the runtime
+will perform the `unsafe` initialization of the singleton for you, ensuring that
+only a single instance of the singleton is ever created.
+
+[`owned-singleton`]: ../../api/owned_singleton/index.html
+[`Singleton`]: ../../api/owned_singleton_macros/attr.Singleton.html
+
+Note that when using the `Singleton` attribute you'll need to have the
+`owned_singleton` in your dependencies.
+
+Below is an example that uses the `Singleton` attribute on a chunk of memory
+and then uses the singleton instance as a fixed-size memory pool using one of
+the [`alloc-singleton`] abstractions.
+
+[`alloc-singleton`]: https://crates.io/crates/alloc-singleton
+
+``` rust
+{{#include ../../../../examples/singleton.rs}}
+```
+
+``` console
+$ cargo run --example singleton
+{{#include ../../../../ci/expected/singleton.run}}```