https://github.com/ydrmaster/rrtt

rt-thread in rust
https://github.com/ydrmaster/rrtt

Last synced: over 1 year ago
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rt-thread in rust

• Host: GitHub
• URL: https://github.com/ydrmaster/rrtt
• Owner: YdrMaster
• Created: 2022-12-22T08:00:11.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2022-12-28T00:05:28.000Z (over 3 years ago)
• Last Synced: 2025-01-21T17:08:32.168Z (over 1 year ago)
• Language: Rust
• Size: 22.5 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# rt-thread in rust

## version 0 (2022-12-22..)

直接翻译 C 版本试试看。

### 2022-12-24

C 里很常见的基于数值的条件编译：

```c

#if RT_THREAD_PRIORITY_MAX <= 32

...

#else

...

#endif

```

在 Rust 里没有对应。

想了一个办法，要求通过环境变量传入这种常量，在 build.rs 里把不同数值范围的环境变量转化为 [`rustc-cfg`](https://doc.rust-lang.org/cargo/reference/build-scripts.html#cargorustc-cfgkeyvalue)。在 build.rs 里这样操作：

```rust

const PRIORITY_MAX: &str = "PRIORITY_MAX";

const PRIORITY_MAX_DEFAULT: usize = 8;

let val = match env::var(PRIORITY_MAX) {

    Ok(s) => match s.parse::() {

        Ok(val) => val,

        Err(_) => panic!("failed to parse env {PRIORITY_MAX}={s:?} for not a number."),

    },

    Err(env::VarError::NotPresent) => {

        println!("cargo:rustc-env={PRIORITY_MAX}={PRIORITY_MAX_DEFAULT}");

        PRIORITY_MAX_DEFAULT

    }

    Err(env::VarError::NotUnicode(_)) => {

        panic!("failed to parse env {PRIORITY_MAX} for not unicode.");

    }

};

println!("cargo:rerun-if-env-changed={PRIORITY_MAX}");

println!(

    "cargo:rustc-cfg={}",

    if val > 32 {

        "large_priority"

    } else {

        "small_priority"

    }

);

```

然后可以在代码里用 `#[cfg(large_priority)]` 或 `#[cfg(small_priority)]` 应用条件。