Following the tutorial produces many warning messages on cargo test

[fwip]

This error occurs at step 5 of the tutorial: https://rust-lang.github.io/rust-bindgen/tutorial-5.html
I am on a Macbook, OS version 11.6 (big sur)

Input C/C++ Header

#include <bzlib.h>

Sorry, I know the template says "no #includes", but I'm not sure how to view the contents of this system header. If there is a specific bzip2.h file that I "should" be using for this tutorial, I am happy to try it.

Bindgen Invocation

build.rs:

extern crate bindgen;

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

fn main() {
    // Tell cargo to tell rustc to link the system bzip2
    // shared library.
    println!("cargo:rustc-link-lib=bz2");

    // Tell cargo to invalidate the built crate whenever the wrapper changes
    println!("cargo:rerun-if-changed=wrapper.h");

    // The bindgen::Builder is the main entry point
    // to bindgen, and lets you build up options for
    // the resulting bindings.
    let bindings = bindgen::Builder::default()
        // The input header we would like to generate
        // bindings for.
        .header("wrapper.h")
        // Tell cargo to invalidate the built crate whenever any of the
        // included header files changed.
        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
        // 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());
    bindings
        .write_to_file(out_path.join("bindings.rs"))
        .expect("Couldn't write bindings!");
}

Actual Results

$ cargo test
   Compiling wxWidgets-rs v0.1.0 (/Volumes/projects/futz/wxWidgets-rs)
warning: panic message is not a string literal
  --> src/lib.rs:59:59
   |
59 |                 r if r == (BZ_PARAM_ERROR as _) => panic!(BZ_PARAM_ERROR),
   |                                                           ^^^^^^^^^^^^^^
   |
   = note: `#[warn(non_fmt_panic)]` on by default
   = note: this is no longer accepted in Rust 2021
help: add a "{}" format string to Display the message
   |
59 |                 r if r == (BZ_PARAM_ERROR as _) => panic!("{}", BZ_PARAM_ERROR),
   |                                                           ^^^^^
help: or use std::panic::panic_any instead
   |
59 |                 r if r == (BZ_PARAM_ERROR as _) => std::panic::panic_any(BZ_PARAM_ERROR),
   |                                                    ^^^^^^^^^^^^^^^^^^^^^

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:239:19
    |
239 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).next_in as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed
    |
    = note: `#[warn(deref_nullptr)]` on by default

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:249:19
    |
249 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).avail_in as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:259:19
    |
259 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).total_in_lo32 as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:269:19
    |
269 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).total_in_hi32 as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:279:19
    |
279 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).next_out as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:289:19
    |
289 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).avail_out as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:299:19
    |
299 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).total_out_lo32 as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:309:19
    |
309 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).total_out_hi32 as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:319:19
    |
319 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).state as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:329:19
    |
329 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).bzalloc as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:339:19
    |
339 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).bzfree as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:349:19
    |
349 |         unsafe { &(*(::std::ptr::null::<bz_stream>())).opaque as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:389:19
    |
389 |         unsafe { &(*(::std::ptr::null::<__mbstate_t>())).__mbstate8 as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:399:19
    |
399 |         unsafe { &(*(::std::ptr::null::<__mbstate_t>()))._mbstateL as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:461:14
    |
461 |             &(*(::std::ptr::null::<__darwin_pthread_handler_rec>())).__routine as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:473:14
    |
473 |             &(*(::std::ptr::null::<__darwin_pthread_handler_rec>())).__arg as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:485:14
    |
485 |             &(*(::std::ptr::null::<__darwin_pthread_handler_rec>())).__next as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:515:19
    |
515 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_attr_t>())).__sig as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:525:19
    |
525 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_attr_t>())).__opaque as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:554:19
    |
554 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_cond_t>())).__sig as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:564:19
    |
564 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_cond_t>())).__opaque as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:594:14
    |
594 |             &(*(::std::ptr::null::<_opaque_pthread_condattr_t>())).__sig as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:606:14
    |
606 |             &(*(::std::ptr::null::<_opaque_pthread_condattr_t>())).__opaque as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:636:19
    |
636 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_mutex_t>())).__sig as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:647:14
    |
647 |             &(*(::std::ptr::null::<_opaque_pthread_mutex_t>())).__opaque as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:678:14
    |
678 |             &(*(::std::ptr::null::<_opaque_pthread_mutexattr_t>())).__sig as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:690:14
    |
690 |             &(*(::std::ptr::null::<_opaque_pthread_mutexattr_t>())).__opaque as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:720:19
    |
720 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_once_t>())).__sig as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:730:19
    |
730 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_once_t>())).__opaque as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:759:19
    |
759 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_rwlock_t>())).__sig as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:770:14
    |
770 |             &(*(::std::ptr::null::<_opaque_pthread_rwlock_t>())).__opaque as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:801:14
    |
801 |             &(*(::std::ptr::null::<_opaque_pthread_rwlockattr_t>())).__sig as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:813:14
    |
813 |             &(*(::std::ptr::null::<_opaque_pthread_rwlockattr_t>())).__opaque as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:844:19
    |
844 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_t>())).__sig as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:855:14
    |
855 |             &(*(::std::ptr::null::<_opaque_pthread_t>())).__cleanup_stack as *const _ as usize
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:866:19
    |
866 |         unsafe { &(*(::std::ptr::null::<_opaque_pthread_t>())).__opaque as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:948:19
    |
948 |         unsafe { &(*(::std::ptr::null::<__sbuf>()))._base as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
   --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:958:19
    |
958 |         unsafe { &(*(::std::ptr::null::<__sbuf>()))._size as *const _ as usize },
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1030:19
     |
1030 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._p as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1040:19
     |
1040 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._r as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1050:19
     |
1050 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._w as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1060:19
     |
1060 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._flags as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1070:19
     |
1070 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._file as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1080:19
     |
1080 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._bf as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1090:19
     |
1090 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._lbfsize as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1100:19
     |
1100 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._cookie as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1110:19
     |
1110 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._close as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1120:19
     |
1120 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._read as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1130:19
     |
1130 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._seek as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1140:19
     |
1140 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._write as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1150:19
     |
1150 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._ub as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1160:19
     |
1160 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._extra as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1170:19
     |
1170 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._ur as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1180:19
     |
1180 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._ubuf as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1190:19
     |
1190 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._nbuf as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1200:19
     |
1200 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._lb as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1210:19
     |
1210 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._blksize as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1220:19
     |
1220 |         unsafe { &(*(::std::ptr::null::<__sFILE>()))._offset as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1877:19
     |
1877 |         unsafe { &(*(::std::ptr::null::<__va_list_tag>())).gp_offset as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1887:19
     |
1887 |         unsafe { &(*(::std::ptr::null::<__va_list_tag>())).fp_offset as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1897:19
     |
1897 |         unsafe { &(*(::std::ptr::null::<__va_list_tag>())).overflow_arg_area as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: dereferencing a null pointer
    --> /Volumes/projects/futz/wxWidgets-rs/target/debug/build/wxWidgets-rs-203d5b329102047f/out/bindings.rs:1907:19
     |
1907 |         unsafe { &(*(::std::ptr::null::<__va_list_tag>())).reg_save_area as *const _ as usize },
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this code causes undefined behavior when executed

warning: 63 warnings emitted

    Finished test [unoptimized + debuginfo] target(s) in 2.35s
     Running unittests (target/debug/deps/wxWidgets_rs-4a3457c2fe935080)

running 16 tests
test bindgen_test_layout___mbstate_t ... ok
test bindgen_test_layout___darwin_pthread_handler_rec ... ok
test bindgen_test_layout___sFILE ... ok
test bindgen_test_layout___sbuf ... ok
test bindgen_test_layout__opaque_pthread_cond_t ... ok
test bindgen_test_layout__opaque_pthread_attr_t ... ok
test bindgen_test_layout___va_list_tag ... ok
test bindgen_test_layout__opaque_pthread_condattr_t ... ok
test bindgen_test_layout__opaque_pthread_mutex_t ... ok
test bindgen_test_layout__opaque_pthread_mutexattr_t ... ok
test bindgen_test_layout__opaque_pthread_once_t ... ok
test bindgen_test_layout__opaque_pthread_rwlock_t ... ok
test bindgen_test_layout__opaque_pthread_rwlockattr_t ... ok
test bindgen_test_layout__opaque_pthread_t ... ok
    block 1: crc = 0x25f07035, combined CRC = 0x25f07035, size = 1180
test bindgen_test_layout_bz_stream ... ok
        bucket sorting ...
        depth      1 has   1172 unresolved strings
        depth      2 has   1039 unresolved strings
        depth      4 has    686 unresolved strings
        depth      8 has    347 unresolved strings
        depth     16 has    110 unresolved strings
        depth     32 has     44 unresolved strings
        depth     64 has      0 unresolved strings
        reconstructing block ...
      1180 in block, 878 after MTF & 1-2 coding, 57+2 syms in use
      initial group 4, [0 .. 1], has 284 syms (32.3%)
      initial group 3, [2 .. 4], has 186 syms (21.2%)
      initial group 2, [5 .. 15], has 207 syms (23.6%)
      initial group 1, [16 .. 58], has 201 syms (22.9%)
      pass 1: size is 1050, grp uses are 3 4 2 9
      pass 2: size is 495, grp uses are 2 4 1 11
      pass 3: size is 494, grp uses are 2 4 0 12
      pass 4: size is 493, grp uses are 2 4 0 12
      bytes: mapping 19, selectors 6, code lengths 56, codes 493
    final combined CRC = 0x25f07035

    [1: huff+mtf rt+rld {0x25f07035, 0x25f07035}]
    combined CRCs: stored = 0x25f07035, computed = 0x25f07035test tests::round_trip_compression_decompression ... ok

test result: ok. 16 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

   Doc-tests wxWidgets-rs

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

Expected Results

I would expect output to match the output shown on the doc page.

There are 2 "errors" to me:

1. The first warning about the panic message not being a string literal - possibly this is a version conflict on my end?
2. The many null dereference warnings, which I understand to be expected behavior with cargo test, but is not mentioned in the tutorial, and is alarming to see as a first-time user.

[LoganDark]

Oh hey, someone else trying to make bindings to wxWidgets - ...

Don't even try, bindgen does not support C++. C++ is so cursed that not even different C++ versions can interact with each other, and bindgen cannot even begin to understand classes

[rustonaut]

Through bindgen could add #![allow(deref_nullptr)] to the alignment tests it generates (which are also not sound, but might be the (currently) best way to do given tests as far as I can tell.)

[lu-zero]

The autogenerated tests should avoid doing that.

[rustonaut]

By now the auto generated tests might be able to use addr_of to get field pointers without de-referencing, preferable in combination with NonNull::dangling() instead of null pointers.

[khklau]

I've run into the same warnings with my Apache2 and APR bindings. It's a relief to hear that the null pointer de-referencing is only in the auto-generated tests.

But yes having this in the explained in FAQ or the tutorial documentation would be nice until a proper solution using addr_of is available.

[kulp]

The null deference warnings are resolved in #2203.

I am pretty sure the message about the string literal is not from bindgen.

Let me know if you think differently.