Is there a standard way to include .c source files?
So far I've been using extern "C" { ... } to expose the functions, compiling .c to an object file, running rustc until ld chokes with an undefined reference, and using the arguments shown after error: linking with 'cc' failed with code 1; note: cc arguments: ... to run cc myobjfile.o ...
Editor's note: This answer predates Rust 1.0 and is no longer applicable.
Luqman gave a hint on IRC; using extern "C" { ... } with #[link_args="src/source.c"]; in the crate file works for me.
Use the cc crate in a build script to compile the C files into a static library and then link the static library to your Rust program:
Cargo.toml
[package]
name = "calling-c"
version = "0.1.0"
authors = ["An Devloper <[email protected]>"]
edition = "2018"
[build-dependencies]
cc = "1.0.28"
build.rs
use cc;
fn main() {
cc::Build::new()
.file("src/example.c")
.compile("foo");
}
src/example.c
#include <stdint.h>
uint8_t testing(uint8_t i) {
return i * 2;
}
src/main.rs
extern "C" {
fn testing(x: u8) -> u8;
}
fn main() {
let a = unsafe { testing(21) };
println!("a = {}", a);
}