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<ol class="chapter"><li><a href="tutorial1.html"><strong aria-hidden="true">1.</strong> Chapter 1</a></li><li><a href="tutorial2.html"><strong aria-hidden="true">2.</strong> Chapter 2</a></li><li><a href="tutorial3.html"><strong aria-hidden="true">3.</strong> Chapter 3</a></li><li><a href="tutorial4.html"><strong aria-hidden="true">4.</strong> Chapter 4</a></li><li><a href="tutorial5.html"><strong aria-hidden="true">5.</strong> Chapter 5</a></li><li><a href="tutorial6.html"><strong aria-hidden="true">6.</strong> Chapter 6</a></li><li><a href="tutorial7.html"><strong aria-hidden="true">7.</strong> Chapter 7</a></li><li><a href="tutorial8.html"><strong aria-hidden="true">8.</strong> Chapter 8</a></li><li><a href="tutorial9.html"><strong aria-hidden="true">9.</strong> Chapter 9</a></li><li><a href="tutorial10.html"><strong aria-hidden="true">10.</strong> Chapter 10</a></li><li><a href="tutorial11.html"><strong aria-hidden="true">11.</strong> Chapter 11</a></li></ol>
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<h1 class="menu-title">chainerror</h1>
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<main>
<a class="header" href="#simple-string-errors" id="simple-string-errors"><h1>Simple String Errors</h1></a>
<p>The most simplest of doing error handling in rust is by returning <code>String</code> as a <code>Box<Error></code>.</p>
<p>As you can see by running the example (the "Play" button in upper right of the code block), this only
prints out the last <code>Error</code>.</p>
<p>If the rust <code>main</code> function returns an Err(), this Err() will be displayed with <code>std::fmt::Debug</code>.</p>
<pre><pre class="playpen"><code class="language-rust">use std::error::Error;
use std::result::Result;
fn do_some_io() -> Result<(), Box<Error>> {
Err("do_some_io error")?;
Ok(())
}
fn func2() -> Result<(), Box<Error>> {
if let Err(_) = do_some_io() {
Err("func2 error")?;
}
Ok(())
}
fn func1() -> Result<(), Box<Error>> {
if let Err(_) = func2() {
Err("func1 error")?;
}
Ok(())
}
fn main() -> Result<(), Box<Error>> {
func1()
}
</code></pre></pre>
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