Dan Gohman 15c27078b5 Detect `main(void)` vs `main(int argc, char *argv[])` in crt1-command.o. Instead of having crt1-command.o always call `__main_void` which is then overridden by the linker, have crt1-command.o use weak symbols and test both symbols for their presence. This should help libc.so, as it mean libc.so won't need to depend on any of the main-related symbols.		1 year ago
.github/workflows	dlmalloc: require __heap_end (#394)	1 year ago
dlmalloc	Acquire the global lock before initializing malloc (#410)	1 year ago
emmalloc	Port emmalloc to wasi-libc.	2 years ago
expected	Detect `main(void)` vs `main(int argc, char *argv[])` in crt1-command.o.	1 year ago
libc-bottom-half	Detect `main(void)` vs `main(int argc, char *argv[])` in crt1-command.o.	1 year ago
libc-top-half	Fix a use-after-free bug for detached threads (#420)	1 year ago
test	test: run a subset of tests using `libc-test` (#346)	2 years ago
tools/wasi-headers	build: update WASI and partially regenerate `api.h`	3 years ago
.gitattributes	Correct the version of #136 on master (#141)	5 years ago
.gitignore	gitignore build	6 years ago
.gitmodules	Correct the version of #136 on master (#141)	5 years ago
CODE_OF_CONDUCT.md	Add a CODE_OF_CONDUCT.md file. (#101)	5 years ago
LICENSE	Beginning porting Emscripten's emmalloc to wasi-libc.	2 years ago
LICENSE-APACHE	Multi-license wasi-libc under Apache and MIT licenses. (#174)	5 years ago
LICENSE-APACHE-LLVM	Multi-license wasi-libc under Apache and MIT licenses. (#174)	5 years ago
LICENSE-MIT	Multi-license wasi-libc under Apache and MIT licenses. (#174)	5 years ago
Makefile	Use -fno-strict-aliasing for emmalloc (#424)	1 year ago
README.md	Improve `README.md` (#425)	1 year ago

README.md

`wasi-libc`

wasi-libc is a libc for WebAssembly programs built on top of WASI system calls. It provides a wide array of POSIX-compatible C APIs, including support for standard I/O, file I/O, filesystem manipulation, memory management, time, string, environment variables, program startup, and many other APIs.

wasi-libc is sufficiently stable and usable for many purposes, as most of the POSIX-compatible APIs are stable, though it is continuing to evolve to better align with wasm and WASI. For example, pthread support is experimentally provided via the wasi-threads proposal.`

Usage

The easiest way to get started with this is to use wasi-sdk, which includes a build of wasi-libc in its sysroot.

Building from source

To build a WASI sysroot from source, obtain a WebAssembly-supporting C compiler (currently this is only clang 10+, though we'd like to support other compilers as well), and then run:

make CC=/path/to/clang/with/wasm/support \
     AR=/path/to/llvm-ar \
     NM=/path/to/llvm-nm

This makes a directory called "sysroot" by default. See the top of the Makefile for customization options.

To use the sysroot, use the --sysroot= option:

/path/to/wasm/supporting/c/compiler --sysroot=/path/to/the/newly/built/sysroot ...

to run the compiler using the newly built sysroot.

Note that Clang packages typically don't include cross-compiled builds of compiler-rt, libcxx, or libcxxabi, for libclang_rt.builtins-wasm32.a, libc++.a, or libc++abi.a, respectively, so they may not be usable without extra setup. This is one of the things wasi-sdk simplifies, as it includes cross-compiled builds of compiler-rt, libc++.a, and libc++abi.a.

Building in pthread support

To enable pthreads support via the wasi-threads proposal, follow the above build directions with one addition: make ... THREAD_MODEL=posix. This creates additional artifacts in sysroot/lib/wasm32-wasi-threads to support --target wasm32-wasi-threads.

Arch Linux AUR package

For Arch Linux users, there's an official wasi-libc package tracking this Git repository. You might want to install other WASI related packages as well.