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Merge pull request #141 from brandonpollack23/static_const

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Added notes, runtime constant eval, and footnoes to static-and-const.md
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Martin Geisler 2023-01-10 18:53:46 +01:00 committed by GitHub
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src/basic-syntax/static-and-const.md
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@ -24,6 +24,8 @@ fn main() {
} }
``` ```
According the the [Rust RFC Book][1] these are inlined upon use.
## `static` ## `static`
You can also declare static variables: You can also declare static variables:
@ -36,4 +38,15 @@ fn main() {
} }
``` ```
As noted in the [Rust RFC Book][1], these are not inlined upon use and have an actual associated memory location. This is useful for unsafe and embedded code, and have a `'static` lifetime.
We will look at mutating static data in the [chapter on Unsafe Rust](../unsafe.md). We will look at mutating static data in the [chapter on Unsafe Rust](../unsafe.md).
<details>
* Mention that `const` behaves semantically similar to C++'s `constexpr`.
* `static`, on the other hand, is much more similar to a `const` or mutable global variable in C++.
* It isn't super common that one would need a runtime evaluated constant, but it is helpful and safer than using a static.
</details>