build.rs

extern crate bindgen;

use std::env;
use std::path::PathBuf;

fn main() {
    if std::env::var("DOCS_RS").is_ok() {
        return;
    }

    println!("cargo:rerun-if-changed=wrapper.h");
    println!("cargo:rerun-if-changed=src/generated.rs");

    let linuxcnc_root = env::var("LINUXCNC_SRC").expect("LINUXCNC_SRC env var must be set and pointing to the root of the LinuxCNC source Git repository");

    let bindings = bindgen::Builder::default()
        // The input header we would like to generate
        // bindings for.
        .header("wrapper.h")
        .clang_arg(&format!("-I{}", linuxcnc_root))
        .clang_arg(&format!("-I{}/src/hal", linuxcnc_root))
        .clang_arg(&format!("-I{}/src/rtapi", linuxcnc_root))
        // Tell LinuxCNC build to run in realtime mode with `-DRTAPI` or non-realtime with `-DULAPI`.
        // See line ~114 in linuxcnc-src/src/hal/hal.h
        .clang_arg("-DRTAPI")
        // FIXME: This currently breaks the doc tests as Rust parses the broken C comment as code.
        .blocklist_function("hal_set_lock")
        // .clang_arg("-DULAPI")
        // Tell cargo to invalidate the built crate whenever any of the
        // included header files changed.
        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
        // Finish the builder and generate the bindings.
        .generate()
        // Unwrap the Result and panic on failure.
        .expect("Unable to generate bindings");

    // Write the bindings to the $OUT_DIR/bindings.rs file.
    // let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());

    let out_path = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("src");

    bindings
        .write_to_file(out_path.join("generated.rs"))
        .expect("Couldn't write bindings!");

    // Dynamically link LinuxCNC HAL, as per <https://github.com/rust-lang/rust-bindgen/issues/1974>
    // and <https://doc.rust-lang.org/cargo/reference/build-scripts.html#rustc-link-lib>

    println!("cargo:rustc-link-search=native={linuxcnc_root}/lib");
    println!("cargo:rustc-link-lib=dylib=linuxcnchal");
    // From
    // <https://stackoverflow.com/questions/40602708/linking-rust-application-with-a-dynamic-library-not-in-the-runtime-linker-search>
    println!("cargo:rustc-link-arg=-Wl,-rpath,{linuxcnc_root}/lib");
}