将 C 数组传递给 Rust 函数 [英] Pass a C array to a Rust function
问题描述
我正在尝试制作 Rust dylib 并从其他语言(如 C、Python 和其他语言)中使用它.我已经成功地调用了一个 Rust 函数,它从 Python 中获取了一个 i32 参数.现在我正在尝试创建一个函数,该函数接受一个数组(或指向它的指针,或者任何将数据集传递给 Rust 所需的任何东西).
I'm trying to make a Rust dylib and use it from other languages, like C, Python and others. I've successfully called a Rust function taking an i32 argument from Python. Now I'm trying to make a function that takes an array (or a pointer to it, or whatever is necessary to pass a dataset to Rust).
#![crate_type = "dylib"]
#[no_mangle]
pub extern "C" fn rust_multiply(size: i32, arrayPointer: &i32) -> i32 {
*(arrayPointer)
}
这按预期工作.但是
#![crate_type = "dylib"]
#[no_mangle]
pub extern "C" fn rust_multiply(size: i32, arrayPointer: &i32) -> i32 {
*(arrayPointer + 1) // trying to get next element
}
失败
error[E0614]: type `i32` cannot be dereferenced
--> src/lib.rs:4:5
|
4 | *(arrayPointer + 1) // trying to get next element
| ^^^^^^^^^^^^^^^^^^^
这样做:
pub extern fn rust_multiply(size: i32, array: &[i32]) -> i32
并且执行诸如 array[0]
之类的操作失败并显示length = 0";错误.
and doing something like array[0]
fails with "length = 0" error.
推荐答案
您必须努力提供纯 C API 并使用不安全的代码实现一些转换.幸运的是,这并不难:
You have to make some efforts to provide a pure C API and implement some conversions using unsafe code. Fortunately, it is not so difficult:
extern crate libc;
#[no_mangle]
pub extern "C" fn rust_multiply(
size: libc::size_t,
array_pointer: *const libc::uint32_t,
) -> libc::uint32_t {
internal_rust_multiply(unsafe {
std::slice::from_raw_parts(array_pointer as *const i32, size as usize)
}) as libc::uint32_t
}
fn internal_rust_multiply(array: &[i32]) -> i32 {
assert!(!array.is_empty());
array[0]
}
Rust FFI 有一个很好的介绍 官方网站.
There is a good introduction for Rust FFI on the official site.
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