| [](https://crates.io/crates/bindgen) | |
| [](https://docs.rs/bindgen/) | |
| # `bindgen` | |
| **`bindgen` automatically generates Rust FFI bindings to C (and some C++) libraries.** | |
| For example, given the C header `doggo.h`: | |
| ```c | |
| 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: | |
| ```rust | |
| /* automatically generated by rust-bindgen 0.99.9 */ | |
| #[repr(C)] | |
| 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! 📚](https://rust-lang.github.io/rust-bindgen) | |
| ## MSRV | |
| The `bindgen` minimum supported Rust version is **1.71.0**. | |
| The `bindgen-cli` minimum supported Rust version is **1.71.0**. | |
| No MSRV bump policy has been established yet, so MSRV may increase in any release. | |
| The MSRV is the minimum Rust version that can be used to *compile* each crate. However, `bindgen` and `bindgen-cli` can generate bindings that are compatible with Rust versions below the current MSRV. | |
| Most of the time, the `bindgen-cli` crate will have a more recent MSRV than `bindgen` as crates such as `clap` require it. | |
| ## API Reference | |
| [API reference documentation is on docs.rs](https://docs.rs/bindgen) | |
| ## Environment Variables | |
| In addition to the [library API](https://docs.rs/bindgen) and [executable command-line API][bindgen-cmdline], | |
| `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][clang-sys-env]. | |
| For more details on how `bindgen` uses `libclang`, see the [`bindgen` users guide][bindgen-book-clang]. | |
| ## Releases | |
| 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). | |
| ## Contributing | |
| [See `CONTRIBUTING.md` for hacking on `bindgen`!](./CONTRIBUTING.md) | |
| [bindgen-cmdline]: https://rust-lang.github.io/rust-bindgen/command-line-usage.html | |
| [clang-sys-env]: https://github.com/KyleMayes/clang-sys#environment-variables | |
| [bindgen-book-clang]: https://rust-lang.github.io/rust-bindgen/requirements.html#clang |