How to handle function-like macros

[guemax]

Consider this project with the following files:

.
├── build.rs
├── mylib.c
├── mylib.h
└── src
    └── main.rs

mylib.h:

#define MIN(a, b) (((a) < (b)) ? (a) : (b))

mylib.c:

#include "mylib.h"

build.rs:

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

fn main() {
    cc::Build::new()
	.flag("-O2")
	.file("mylib.c")
        .compile("mylib");

    let bindings = bindgen::Builder::default()
	.header("mylib.h")
        .parse_callbacks(Box::new(bindgen::CargoCallbacks::new()))
	.generate()
        .expect("Unable to generate bindings");

    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
    bindings
        .write_to_file(out_path.join("bindings.rs"))
        .expect("Couldn't write bindings!");
}

src/main.rs:

mod mylib {
    #![allow(non_upper_case_globals)]
    #![allow(non_camel_case_types)]
    #![allow(non_snake_case)]
    #![allow(dead_code)]

    include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
}

fn main() {
    println!("{}", mylib::MIN(0, 1));
}

Running cargo build will fail with error[E0425]: cannot find function, tuple struct or tuple variant 'MIN' in module 'mylib', looking at bindings.rs inside target/ reveals that no bindings have been generated for MIN.

It looks like func_macro callback allows you to semi-automatically generate these bindings, I'd appreciate a small example for the code above. I already looked at #753 and #1793 but I still cannot wrap my head around it.

Thank you in advance for your help!

[qinghon]

bindgen does not generate func-like macro by default, which requires a very complex implementation (to solve type problems). There is currently a #2369 example implementation

However, if you just want to simply add your own implementation, can use syn to parse the file generated by bindgen and append your function