Avoid case of a self-referential type alias.

This previously produced a type alias which referred to itself,
which was clearly wrong and resulted in downstream code recursing

The problem case (per bug #2102) is:

  template <typename> class B{};
  template <typename c> class C {
    using U = B<c>;
  class A : C<A> {
    U u;

As far as I can tell, we parse clang's definition of B<A>; that leads
us to parse A; to find it has a field U which turns out to be of type
B<A>. And so we hit the line in item.rs which says:
  debug!("Avoiding recursion parsing type: {:?}", ty);
and bail out, returning the original item ID: hence, a self-
referential typedef is created.

The 'fix' in this PR creates an opaque type in this case instead,
to avoid later infinite loops. It would be preferable to avoid this
situation in the first place, but presumably that would require
us to split the parsing phase into two:
1) types
2) fields within those types.

Fixes #2102.
3 files changed
tree: 818c72154e1969c1f093fa06e00b831e87830449
  1. .github/
  2. bindgen-integration/
  3. book/
  4. ci/
  5. csmith-fuzzing/
  6. releases/
  7. src/
  8. tests/
  9. .gitattributes
  10. .gitignore
  11. appveyor.yml
  12. build.rs
  13. Cargo.lock
  14. Cargo.toml
  15. CHANGELOG.md
  17. example-graphviz-ir.png
  19. README.md
  20. rustfmt.toml

crates.io docs.rs


bindgen automatically generates Rust FFI bindings to C (and some C++) libraries.

For example, given the C header doggo.h:

typedef struct Doggo {
    int many;
    char wow;
} Doggo;

void eleven_out_of_ten_majestic_af(Doggo* pupper);

bindgen produces Rust FFI code allowing you to call into the doggo library's functions and use its types:

/* automatically generated by rust-bindgen 0.99.9 */

pub struct Doggo {
    pub many: ::std::os::raw::c_int,
    pub wow: ::std::os::raw::c_char,

extern "C" {
    pub fn eleven_out_of_ten_majestic_af(pupper: *mut Doggo);

Users Guide

📚 Read the bindgen users guide here! 📚


The minimum supported Rust version is 1.46.

No MSRV bump policy has been established yet, so MSRV may increase in any release.

API Reference

API reference documentation is on docs.rs

Environment Variables

In addition to the library API and executable command-line API, bindgen can be controlled through environment variables.

End-users should set these environment variables to modify bindgen's behavior without modifying the source code of direct consumers of bindgen.

  • BINDGEN_EXTRA_CLANG_ARGS: extra arguments to pass to clang
    • Arguments are whitespace-separated
    • Use shell-style quoting to pass through whitespace
    • Examples:
      • Specify alternate sysroot: --sysroot=/path/to/sysroot
      • Add include search path with spaces: -I"/path/with spaces"
  • BINDGEN_EXTRA_CLANG_ARGS_<TARGET>: similar to BINDGEN_EXTRA_CLANG_ARGS, but used to set per-target arguments to pass to clang. Useful to set system include directories in a target-specific way in cross-compilation environments with multiple targets. Has precedence over BINDGEN_EXTRA_CLANG_ARGS.

Additionally, bindgen uses libclang to parse C and C++ header files. To modify how bindgen searches for libclang, see the clang-sys documentation. For more details on how bindgen uses libclang, see the bindgen users guide.


We don't follow a specific release calendar, but if you need a release please file an issue requesting that (ping @emilio for increased effectiveness).


See CONTRIBUTING.md for hacking on bindgen!