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<ol class="chapter"><li class="chapter-item expanded affix "><a href="../preface.html">Preface</a></li><li class="chapter-item expanded "><a href="../by-example.html"><strong aria-hidden="true">1.</strong> RTIC by example</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../by-example/app.html"><strong aria-hidden="true">1.1.</strong> The app</a></li><li class="chapter-item expanded "><a href="../by-example/resources.html"><strong aria-hidden="true">1.2.</strong> Resources</a></li><li class="chapter-item expanded "><a href="../by-example/app_init.html"><strong aria-hidden="true">1.3.</strong> The init task</a></li><li class="chapter-item expanded "><a href="../by-example/app_idle.html"><strong aria-hidden="true">1.4.</strong> The idle task</a></li><li class="chapter-item expanded "><a href="../by-example/app_task.html"><strong aria-hidden="true">1.5.</strong> Defining tasks</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../by-example/hardware_tasks.html"><strong aria-hidden="true">1.5.1.</strong> Hardware tasks</a></li><li class="chapter-item expanded "><a href="../by-example/software_tasks.html"><strong aria-hidden="true">1.5.2.</strong> Software tasks & spawn</a></li><li class="chapter-item expanded "><a href="../by-example/message_passing.html"><strong aria-hidden="true">1.5.3.</strong> Message passing & capacity</a></li><li class="chapter-item expanded "><a href="../by-example/app_priorities.html"><strong aria-hidden="true">1.5.4.</strong> Task priorities</a></li><li class="chapter-item expanded "><a href="../by-example/monotonic.html"><strong aria-hidden="true">1.5.5.</strong> Monotonic & spawn_{at/after}</a></li></ol></li><li class="chapter-item expanded "><a href="../by-example/starting_a_project.html"><strong aria-hidden="true">1.6.</strong> Starting a new project</a></li><li class="chapter-item expanded "><a href="../by-example/app_minimal.html"><strong aria-hidden="true">1.7.</strong> The minimal app</a></li><li class="chapter-item expanded "><a href="../by-example/tips.html"><strong aria-hidden="true">1.8.</strong> Tips & Tricks</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../by-example/tips_monotonic_impl.html"><strong aria-hidden="true">1.8.1.</strong> Implementing Monotonic</a></li><li class="chapter-item expanded "><a href="../by-example/tips_destructureing.html"><strong aria-hidden="true">1.8.2.</strong> Resource de-structure-ing</a></li><li class="chapter-item expanded "><a href="../by-example/tips_indirection.html"><strong aria-hidden="true">1.8.3.</strong> Avoid copies when message passing</a></li><li class="chapter-item expanded "><a href="../by-example/tips_static_lifetimes.html" class="active"><strong aria-hidden="true">1.8.4.</strong> 'static super-powers</a></li><li class="chapter-item expanded "><a href="../by-example/tips_view_code.html"><strong aria-hidden="true">1.8.5.</strong> Inspecting generated code</a></li><li class="chapter-item expanded "><a href="../by-example/tips_from_ram.html"><strong aria-hidden="true">1.8.6.</strong> Running tasks from RAM</a></li></ol></li></ol></li><li class="chapter-item expanded "><a href="../awesome_rtic.html"><strong aria-hidden="true">2.</strong> Awesome RTIC examples</a></li><li class="chapter-item expanded "><a href="../migration.html"><strong aria-hidden="true">3.</strong> Migration Guides</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../migration/migration_v5.html"><strong aria-hidden="true">3.1.</strong> v0.5.x to v1.0.x</a></li><li class="chapter-item expanded "><a href="../migration/migration_v4.html"><strong aria-hidden="true">3.2.</strong> v0.4.x to v0.5.x</a></li><li class="chapter-item expanded "><a href="../migration/migration_rtic.html"><strong aria-hidden="true">3.3.</strong> RTFM to RTIC</a></li></ol></li><li class="chapter-item expanded "><a href="../internals.html"><strong aria-hidden="true">4.</strong> Under the hood</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../internals/targ
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<h1 class="menu-title">Real-Time Interrupt-driven Concurrency</h1>
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<h1 id="static-super-powers"><a class="header" href="#static-super-powers">'static super-powers</a></h1>
<p>In <code>#[init]</code> and <code>#[idle]</code> <code>local</code> resources have <code>'static</code> lifetime.</p>
<p>Useful when pre-allocating and/or splitting resources between tasks, drivers
or some other object.
This comes in handy when drivers, such as USB drivers, need to allocate memory and
when using splittable data structures such as <a href="https://docs.rs/heapless/0.7.5/heapless/spsc/struct.Queue.html"><code>heapless::spsc::Queue</code></a>.</p>
<p>In the following example two different tasks share a <a href="https://docs.rs/heapless/0.7.5/heapless/spsc/struct.Queue.html"><code>heapless::spsc::Queue</code></a>
for lock-free access to the shared queue.</p>
<pre><pre class="playground"><code class="language-rust"><span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>//! examples/static.rs
#![deny(unsafe_code)]
#![deny(warnings)]
#![deny(missing_docs)]
#![no_main]
#![no_std]
use panic_semihosting as _;
#[rtic::app(device = lm3s6965, dispatchers = [UART0])]
mod app {
use cortex_m_semihosting::{debug, hprintln};
use heapless::spsc::{Consumer, Producer, Queue};
#[shared]
struct Shared {}
#[local]
struct Local {
p: Producer&lt;'static, u32, 5&gt;,
c: Consumer&lt;'static, u32, 5&gt;,
}
#[init(local = [q: Queue&lt;u32, 5&gt; = Queue::new()])]
fn init(cx: init::Context) -&gt; (Shared, Local, init::Monotonics) {
// q has 'static life-time so after the split and return of `init`
// it will continue to exist and be allocated
let (p, c) = cx.local.q.split();
foo::spawn().unwrap();
(Shared {}, Local { p, c }, init::Monotonics())
}
#[idle(local = [c])]
fn idle(c: idle::Context) -&gt; ! {
loop {
// Lock-free access to the same underlying queue!
if let Some(data) = c.local.c.dequeue() {
hprintln!("received message: {}", data);
// Run foo until data
if data == 3 {
debug::exit(debug::EXIT_SUCCESS); // Exit QEMU simulator
} else {
foo::spawn().unwrap();
}
}
}
}
#[task(local = [p, state: u32 = 0])]
fn foo(c: foo::Context) {
*c.local.state += 1;
// Lock-free access to the same underlying queue!
c.local.p.enqueue(*c.local.state).unwrap();
}
}
<span class="boring">}</span></code></pre></pre>
<p>Running this program produces the expected output.</p>
<pre><code class="language-console">$ cargo run --target thumbv7m-none-eabi --example static
received message: 1
received message: 2
received message: 3
</code></pre>
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