no_error

为no_std + no_alloc Rust的错误库

• 宏将字符串字面量转换为C风格字符数组
• 不需要分配器
• 支持非C字符串文本（即 len + string）
• 如果文本不是选项，则支持错误代码

use no_error::*;

extern "C" {
    fn print(x: const *u8); // takes in a c-string
    fn print_with_len(x: const *u8, len usize); // takes in text and length
}

const FAIL:ErrorCode = 42;

fn can_fail(i:i32) -> Result<()> {
    if i < 0 { 
        // programmatically appends a "/0" to end of static string
        error_message!("a failure happened","it happened in can_fail()")
    } else if i == 0 {
        // don't like c strings? supports failure codes too
        error_code!(FAIL)
    } else {
        // you don't have to specify the source if you don't want
        error_message!("a failure happened")
    }
}

fn main() {
    match can_fail(42) {
        Ok(_) => (),
        Err(a) => {
            print(a.cstr_description());
            let source = a.source();
            print_with_len(source.as_ptr(),source.len());
            if let Some(c) = a.code() {
                if c == FAIL {
                    print("secret of life".as_ptr());
                }
            }
        },
    };
}