1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

// Copyright 2026 Google LLC
// SPDX-License-Identifier: Apache-2.0
use std::ffi::{CStr, c_char};
use std::time::{SystemTime, SystemTimeError, UNIX_EPOCH};

unsafe extern "C" {
    /// 基于时间戳 `t` 创建格式化时间。
    fn ctime(t: *const libc::time_t) -> *const c_char;
}

fn now_formatted() -> Result<String, SystemTimeError> {
    let now = SystemTime::now().duration_since(UNIX_EPOCH)?;
    let seconds = now.as_secs() as i64;

    // SAFETY: `seconds` 由系统时钟生成，不会导致溢出
    let ptr = unsafe { ctime(&seconds) };

    // SAFETY: ctime 返回指向预分配（非空）缓冲区的指针
    let ptr = unsafe { CStr::from_ptr(ptr) };

    // SAFETY: ctime 使用有效的 UTF-8
    let fmt = ptr.to_str().unwrap();

    Ok(fmt.trim_end().to_string())
}

fn main() {
    let t = now_formatted();
    println!("{t:?}");
}