dtolnay/cxx

Handle &CStr <-> const char*

Open

#681 创建于 2021年1月16日

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 (2 评论) (2 反应) (0 负责人)Rust (4,472 star) (253 fork)batch import
help wanted

描述

For a C++ function like this:

void example(const char *s);

it should work to call it as:

use std::ffi::CStr;

#[cxx::bridge]
mod ffi {
    unsafe extern "C++" {
        fn example(s: &CStr);
    }
}

fn main() {
    let cstr = CStr::from_bytes_with_nul(b"test\0").unwrap();
    ffi::example(cstr);
}

贡献者指南

技术栈
rustcpp
领域
apideveloper experience
议题类型
feature
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
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fresh
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
Rust FFIC++cxx interopCStr
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
40
研究方向
The issue requests support for passing &CStr to C++ functions expecting const char*. The implementation likely requires adding a new type mapping in the cxx codegen. Start by examining how cxx handles existing string types (e.g., CxxString) in the 'types' module of the cxx crate. Look at the code generation for extern functions to see how argument types are translated. The conversion from &CStr to const char* should involve getting the raw pointer from the CStr. Check if there are any existing discussions or PRs related to CStr support. The solution should ensure safety and proper lifetime handling.