We generate invalid code for varargs functions (test-case: rocksdb)

[zhangjinpeng87]

When I use libbindgen with rocksdb, code in bindings.rs doesn't work.

build.rs

extern crate libbindgen;

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

fn main() {
    // Tell Cargo to tell rustc to link the system rocksdb shared library.
    println!("cargo:rustc-link-lib=rocksdb");

    let bindings = libbindgen::Builder::default()
        .no_unstable_rust()
        .clang_arg("-std=c++11")
        .header("wrapper.hpp")
        .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!");
}

code snip in bindings.rs

impl std_namespace___any {
    #[inline]
    pub unsafe fn new(, ...) -> Self { // doesn't work
    ¦   let mut __bindgen_tmp = ::std::mem::uninitialized();
    ¦   std_namespace___any___any(&mut __bindgen_tmp);
    ¦   __bindgen_tmp
    }
}

[emilio]

Can you post your wrapper.hpp and your bindings.rs file? We don't support varargs functions right now (and I don't think we can support them properly), but we should skip generating code for them. That's a known defect, but there are several things you can do to work around this known defects when binding C++. The unofficial guide is here: * #342 (comment) But we should definitely clean that up and write up a user guide to how to use bindgen effectively with C++, since it may not be as straight-forward as binding to C libraries. I'm leaving this open to track the varargs constructor (and functions in general) issue. Thanks for reporting this!

…

On Mon, Dec 26, 2016 at 12:01:17AM -0800, zhangjinpeng1987 wrote: When I use `libbindgen` with rocksdb, code in bindings.rs doesn't work. build.rs ``` extern crate libbindgen; use std::env; use std::path::PathBuf; fn main() { // Tell Cargo to tell rustc to link the system rocksdb shared library. println!("cargo:rustc-link-lib=rocksdb"); let bindings = libbindgen::Builder::default() .no_unstable_rust() .clang_arg("-std=c++11") .header("wrapper.hpp") .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!"); } ``` code snip in bindings.rs ``` impl std_namespace___any { #[inline] pub unsafe fn new(, ...) -> Self { // doesn't work ¦ let mut __bindgen_tmp = ::std::mem::uninitialized(); ¦ std_namespace___any___any(&mut __bindgen_tmp); ¦ __bindgen_tmp } } ``` -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: #361

[zhangjinpeng87]

@emilio Thanks for your response. The following is my wrapper.hpp file

// bindgen-flags: -- -std=c++11

#ifndef WRAPPER_HPP
#define WRAPPER_HPP

#include <rocksdb/db.h>

#endif /* !WRAPPER_HPP */

[emilio]

This is now fixed, see #402

[fitzgen]

This is now fixed, see #402