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+# Inspecting generated code
+
+`#[rtic::app]` is a procedural macro that produces support code. If for some
+reason you need to inspect the code generated by this macro you have two
+options:
+
+You can inspect the file `rtic-expansion.rs` inside the `target` directory. This
+file contains the expansion of the `#[rtic::app]` item (not your whole program!)
+of the *last built* (via `cargo build` or `cargo check`) RTIC application. The
+expanded code is not pretty printed by default so you'll want to run `rustfmt`
+on it before you read it.
+
+``` console
+$ cargo build --example foo
+
+$ rustfmt target/rtic-expansion.rs
+
+$ tail target/rtic-expansion.rs
+```
+
+``` rust
+#[doc = r" Implementation details"]
+mod app {
+    #[doc = r" Always include the device crate which contains the vector table"]
+    use lm3s6965 as _;
+    #[no_mangle]
+    unsafe extern "C" fn main() -> ! {
+        rtic::export::interrupt::disable();
+        let mut core: rtic::export::Peripherals = core::mem::transmute(());
+        core.SCB.scr.modify(|r| r | 1 << 1);
+        rtic::export::interrupt::enable();
+        loop {
+            rtic::export::wfi()
+        }
+    }
+}
+```
+
+Or, you can use the [`cargo-expand`] sub-command. This sub-command will expand
+*all* the macros, including the `#[rtic::app]` attribute, and modules in your
+crate and print the output to the console.
+
+[`cargo-expand`]: https://crates.io/crates/cargo-expand
+
+``` console
+$ # produces the same output as before
+$ cargo expand --example smallest | tail
+```