1libc 2==== 3 4Raw FFI bindings to platform libraries like `libc`. 5 6[](https://travis-ci.org/rust-lang/libc) 7[](https://ci.appveyor.com/project/rust-lang-libs/libc) 8[](https://crates.io/crates/libc) 9[](https://docs.rs/libc) 10 11 12 13## Usage 14 15First, add the following to your `Cargo.toml`: 16 17```toml 18[dependencies] 19libc = "0.2" 20``` 21 22Next, add this to your crate root: 23 24```rust 25extern crate libc; 26``` 27 28Currently libc by default links to the standard library, but if you would 29instead like to use libc in a `#![no_std]` situation or crate you can request 30this via: 31 32```toml 33[dependencies] 34libc = { version = "0.2", default-features = false } 35``` 36 37By default libc uses private fields in structs in order to enforce a certain 38memory alignment on them. These structs can be hard to instantiate outside of 39libc. To make libc use `#[repr(align(x))]`, instead of the private fields, 40activate the *align* feature. This requires Rust 1.25 or newer: 41 42```toml 43[dependencies] 44libc = { version = "0.2", features = ["align"] } 45``` 46 47## What is libc? 48 49The primary purpose of this crate is to provide all of the definitions necessary 50to easily interoperate with C code (or "C-like" code) on each of the platforms 51that Rust supports. This includes type definitions (e.g. `c_int`), constants 52(e.g. `EINVAL`) as well as function headers (e.g. `malloc`). 53 54This crate does not strive to have any form of compatibility across platforms, 55but rather it is simply a straight binding to the system libraries on the 56platform in question. 57 58## Public API 59 60This crate exports all underlying platform types, functions, and constants under 61the crate root, so all items are accessible as `libc::foo`. The types and values 62of all the exported APIs match the platform that libc is compiled for. 63 64More detailed information about the design of this library can be found in its 65[associated RFC][rfc]. 66 67[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/1291-promote-libc.md 68 69## Adding an API 70 71Want to use an API which currently isn't bound in `libc`? It's quite easy to add 72one! 73 74The internal structure of this crate is designed to minimize the number of 75`#[cfg]` attributes in order to easily be able to add new items which apply 76to all platforms in the future. As a result, the crate is organized 77hierarchically based on platform. Each module has a number of `#[cfg]`'d 78children, but only one is ever actually compiled. Each module then reexports all 79the contents of its children. 80 81This means that for each platform that libc supports, the path from a 82leaf module to the root will contain all bindings for the platform in question. 83Consequently, this indicates where an API should be added! Adding an API at a 84particular level in the hierarchy means that it is supported on all the child 85platforms of that level. For example, when adding a Unix API it should be added 86to `src/unix/mod.rs`, but when adding a Linux-only API it should be added to 87`src/unix/notbsd/linux/mod.rs`. 88 89If you're not 100% sure at what level of the hierarchy an API should be added 90at, fear not! This crate has CI support which tests any binding against all 91platforms supported, so you'll see failures if an API is added at the wrong 92level or has different signatures across platforms. 93 94With that in mind, the steps for adding a new API are: 95 961. Determine where in the module hierarchy your API should be added. 972. Add the API. 983. Send a PR to this repo. 994. Wait for CI to pass, fixing errors. 1005. Wait for a merge! 101 102### Test before you commit 103 104We have two automated tests running on [Travis](https://travis-ci.org/rust-lang/libc): 105 1061. [`libc-test`](https://github.com/alexcrichton/ctest) 107 - `cd libc-test && cargo test` 108 - Use the `skip_*()` functions in `build.rs` if you really need a workaround. 1092. Style checker 110 - `rustc ci/style.rs && ./style src` 111 112### Releasing your change to crates.io 113 114Now that you've done the amazing job of landing your new API or your new 115platform in this crate, the next step is to get that sweet, sweet usage from 116crates.io! The only next step is to bump the version of libc and then publish 117it. If you'd like to get a release out ASAP you can follow these steps: 118 1191. Update the version number in `Cargo.toml`, you'll just be bumping the patch 120 version number. 1212. Run `cargo update` to regenerate the lockfile to encode your version bump in 122 the lock file. You may pull in some other updated dependencies, that's ok. 1233. Send a PR to this repository. It should [look like this][example], but it'd 124 also be nice to fill out the description with a small rationale for the 125 release (any rationale is ok though!) 1264. Once merged the release will be tagged and published by one of the libc crate 127 maintainers. 128 129[example]: https://github.com/rust-lang/libc/pull/583 130 131## Platforms and Documentation 132 133The following platforms are currently tested and have documentation available: 134 135Tested: 136 * [`i686-pc-windows-msvc`](https://rust-lang.github.io/libc/i686-pc-windows-msvc/libc/) 137 * [`x86_64-pc-windows-msvc`](https://rust-lang.github.io/libc/x86_64-pc-windows-msvc/libc/) 138 (Windows) 139 * [`i686-pc-windows-gnu`](https://rust-lang.github.io/libc/i686-pc-windows-gnu/libc/) 140 * [`x86_64-pc-windows-gnu`](https://rust-lang.github.io/libc/x86_64-pc-windows-gnu/libc/) 141 * [`i686-apple-darwin`](https://rust-lang.github.io/libc/i686-apple-darwin/libc/) 142 * [`x86_64-apple-darwin`](https://rust-lang.github.io/libc/x86_64-apple-darwin/libc/) 143 (OSX) 144 * `i386-apple-ios` 145 * `x86_64-apple-ios` 146 * [`i686-unknown-linux-gnu`](https://rust-lang.github.io/libc/i686-unknown-linux-gnu/libc/) 147 * [`x86_64-unknown-linux-gnu`](https://rust-lang.github.io/libc/x86_64-unknown-linux-gnu/libc/) 148 (Linux) 149 * [`x86_64-unknown-linux-musl`](https://rust-lang.github.io/libc/x86_64-unknown-linux-musl/libc/) 150 (Linux MUSL) 151 * [`aarch64-unknown-linux-gnu`](https://rust-lang.github.io/libc/aarch64-unknown-linux-gnu/libc/) 152 (Linux) 153 * `aarch64-unknown-linux-musl` 154 (Linux MUSL) 155 * [`sparc64-unknown-linux-gnu`](https://rust-lang.github.io/libc/sparc64-unknown-linux-gnu/libc/) 156 (Linux) 157 * [`mips-unknown-linux-gnu`](https://rust-lang.github.io/libc/mips-unknown-linux-gnu/libc/) 158 * [`arm-unknown-linux-gnueabihf`](https://rust-lang.github.io/libc/arm-unknown-linux-gnueabihf/libc/) 159 * [`arm-linux-androideabi`](https://rust-lang.github.io/libc/arm-linux-androideabi/libc/) 160 (Android) 161 * [`x86_64-unknown-freebsd`](https://rust-lang.github.io/libc/x86_64-unknown-freebsd/libc/) 162 * [`x86_64-unknown-openbsd`](https://rust-lang.github.io/libc/x86_64-unknown-openbsd/libc/) 163 * [`x86_64-rumprun-netbsd`](https://rust-lang.github.io/libc/x86_64-unknown-netbsd/libc/) 164 165The following may be supported, but are not guaranteed to always work: 166 167 * `i686-unknown-freebsd` 168 * [`x86_64-unknown-bitrig`](https://rust-lang.github.io/libc/x86_64-unknown-bitrig/libc/) 169 * [`x86_64-unknown-dragonfly`](https://rust-lang.github.io/libc/x86_64-unknown-dragonfly/libc/) 170 * `i686-unknown-haiku` 171 * `x86_64-unknown-haiku` 172 * [`x86_64-unknown-netbsd`](https://rust-lang.github.io/libc/x86_64-unknown-netbsd/libc/) 173 * [`x86_64-sun-solaris`](https://rust-lang.github.io/libc/x86_64-sun-solaris/libc/) 174
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