From: Ralf Jung <post@ralfj.de>
Date: Thu, 17 Nov 2022 13:52:50 +0000 (+0100)
Subject: update uninit example so that it still works in current Rust
X-Git-Url: https://git.ralfj.de/web.git/commitdiff_plain/b3fe05ec61912f50ffe51ddabf9822bcd3ac5aaa?hp=ed3579d7d6ad285fefc257e67bf65c8a9e963e99

update uninit example so that it still works in current Rust
---

diff --git a/personal/_posts/2019-07-14-uninit.md b/personal/_posts/2019-07-14-uninit.md
index e5d973b..bbb1468 100644
--- a/personal/_posts/2019-07-14-uninit.md
+++ b/personal/_posts/2019-07-14-uninit.md
@@ -40,14 +40,16 @@ fn always_returns_true(x: u8) -> bool {
 }
 
 fn main() {
-    let x: u8 = unsafe { mem::uninitialized() };
+    let x: u8 = unsafe { mem::MaybeUninit::uninit().assume_init() };
     assert!(always_returns_true(x));
 }
 {% endhighlight %}
+**Update (2022-11-17):** Switched to `MaybeUninit` to keep the example working in newer versions of Rust.
+
 `always_returns_true` is a function that, clearly, will return `true` for any possible 8-bit unsigned integer.
 After all, *every* possible value for `x` will be either less than 120, equal to 120, or bigger than 120.
 A quick loop [confirms this](https://play.rust-lang.org/?version=stable&mode=release&edition=2018&gist=65b690fa3c1691e11d4d45955358cdbe).
-However, if you [run the example](https://play.rust-lang.org/?version=stable&mode=release&edition=2018&gist=812fe3c8655bfedcea37bb18bb70a945), you can see the assertion fail.[^godbolt]
+However, if you [run the example](https://play.rust-lang.org/?version=stable&mode=release&edition=2018&gist=c17d299cacd626c572def0c4262aed69), you can see the assertion fail.[^godbolt]
 
 [^godbolt]: In case this changes with future Rust versions, [here is the same example on godbolt](https://godbolt.org/z/9G67hP); the `xor eax, eax` indicates that the function returns 0, aka `false`. And [here is a version for C++](https://godbolt.org/z/TWrvcq).