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94d34a13 | 1 | # WASI Libc |
dcf13b6f | 2 | |
c33ea73e DG |
3 | WASI Libc is a libc for WebAssembly programs built on top of WASI system calls. |
4 | It provides a wide array of POSIX-compatible C APIs, including support for | |
5 | standard I/O, file I/O, filesystem manipulation, memory management, time, string, | |
6 | environment variables, program startup, and many other APIs. | |
dcf13b6f | 7 | |
c33ea73e DG |
8 | WASI Libc is sufficiently stable and usable for many purposes, as most of the |
9 | POSIX-compatible APIs are stable, though it is continuing to evolve to better | |
10 | align with wasm and WASI. | |
dcf13b6f DG |
11 | |
12 | ## Usage | |
13 | ||
c33ea73e DG |
14 | The easiest way to get started with this is to use [wasi-sdk], which includes a |
15 | build of WASI Libc in its sysroot. | |
320054e8 DG |
16 | |
17 | ## Building from source | |
18 | ||
19 | To build a WASI sysroot from source, obtain a WebAssembly-supporting C compiler | |
b1e234b6 | 20 | (currently this is only clang 8+, though we'd like to support other compilers as well), |
320054e8 | 21 | and then run: |
dcf13b6f | 22 | |
b1e234b6 | 23 | ```sh |
9e09e02a | 24 | make CC=/path/to/clang/with/wasm/support \ |
9eb4a995 | 25 | AR=/path/to/llvm-ar \ |
a279514a | 26 | NM=/path/to/llvm-nm |
dcf13b6f DG |
27 | ``` |
28 | ||
c9850bfd | 29 | This makes a directory called "sysroot", by default. See the top of the Makefile |
dcf13b6f DG |
30 | for customization options. |
31 | ||
32 | To use the sysroot, use the `--sysroot=` option: | |
33 | ||
b1e234b6 | 34 | ```sh |
dcf13b6f | 35 | /path/to/wasm/supporting/c/compiler --sysroot=/path/to/the/newly/built/sysroot ... |
f2049d9b | 36 | ``` |
dcf13b6f DG |
37 | |
38 | to run the compiler using the newly built sysroot. | |
c33ea73e DG |
39 | |
40 | Note that Clang packages typically don't include cross-compiled builds of | |
42e6901e DG |
41 | compiler-rt, libcxx, or libcxxabi, for `libclang_rt.builtins-wasm32.a`, libc++.a, |
42 | or libc++abi.a, respectively, so they may not be usable without | |
c33ea73e | 43 | extra setup. This is one of the things [wasi-sdk] simplifies, as it includes |
42e6901e | 44 | cross-compiled builds of compiler-rt, libc++.a, and libc++abi.a. |
c33ea73e | 45 | |
ca4d2f0c ZL |
46 | ## Arch Linux AUR package |
47 | For Arch Linux users, there's an unofficial AUR package tracking this git repo that can be installed under the name [wasi-libc-git]. | |
b6390079 | 48 | |
c33ea73e | 49 | [wasi-sdk]: https://github.com/WebAssembly/wasi-sdk |
b6390079 | 50 | [wasi-libc-git]: https://aur.archlinux.org/packages/wasi-libc-git/ |