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WebAssembly
wasi-libc
C2021–2026
WebAssembly / wasi-libc

wasi-libc

WASI libc implementation for WebAssembly

8Distinct people
13Mentions
0Explicit recommenders
1KGitHub stars
REPOSITORY AT A GLANCE

What to know before exploring

What it is

WASI libc implementation for WebAssembly

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

No recommendation phrase was found in the indexed comments.

No classified warning is attached to this page. Read the discussions before treating silence as approval.

Also in these discussions

No other repository is repeatedly linked in the same discussions.

This week on Hacker News

Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 11:34:28 AM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year13 dated mentions

Observed mentions: 2021-07-15 02:50:00 UTC to 2026-08-20 08:27:28 UTC.

02462021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments20212022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments20232024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 0 mentions; 0 submissions, 0 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 7 mentions; 1 submissions, 6 comments2026-01-01 00:00:00 UTC to 2027-01-01 00:00:00 UTC (exclusive): 2 mentions; 0 submissions, 2 comments. Incomplete calendar period.2026*

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC202
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC101
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC101
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC000
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC716
2026 (partial)2026-01-01 00:00:00 UTC2027-01-01 00:00:00 UTC202

What Hacker News says

7 sources
Yeah, using LLVM for anything trying to avoid UB is crazy. I got involved in a discussion with a Rust guy when trying to get C with SIMD intrinsics into wasi-libc where something that the C standard explicitly state is “implementation defined” (and so, sane, as we're targeting a single implementation - LLVM) can't be trusted, because LLVM may turn it back into UB because “reasons.” At this point Go and Zig made the right choice to dump it. I don't know about Rust. https://github.com/WebAssembly/wasi-libc/pull/593
In New Aarch64 Back End
ncruces·May 9, 2025Submission

Show HN: SIMD Optimized Wasm Libc

It's been a little under a month since I submitted the initial bits of this: https://news.ycombinator.com/item?id=43730458 I was asked to upstream (which I tried to, it's the linked issue), and about additional functions. Since then, the issue hasn't gained a lot of traction, but I implemented a few far more interesting algorithms, both by Wojciech Muła: SIMDized check which bytes are in a set: http://0x80.pl/notesen/2018-10-18-simd-byte-lookup.html (for strspn and strcspn). SIMD-friendly algorithms for substring searching: http://0x80.pl/notesen/2016-11-28-simd-strfind.html (for strstr and memmem). These basically "complete" the set of string.h methods. I also made sure the header compiles with C++, added a bunch of tests, and made it easier to integrate in your stuff if even it doesn't get upstreamed. If you're interested in diving into
Read the rest
3 points · Open discussion
> The problem is that in WASM-land we're heading towards WASI and WAT components, which is similar to the .NET, COM & IDL ecosystems. While this is actually really cool in terms of component and interface discovery, the downside is that it means you have to re-invent the world to work with this flavor of runtime. At the application level, you're generally going to write to the standards + your embedding. Companies that write embeddings are encouraced/incentivized to write good abstractions that work with standards to reduce user friction. For example, for making HTTP requests and responding to HTTP requests, there is WASI HTTP: https://github.com/WebAssembly/wasi-http It's written in a way that is robust enough to handle most use cases without much loss of efficiency. There are a few inefficiencies in the WIT contracts (that will go away
Read the rest
soon, as async lands in p3), but it represents a near-ideal representation of a HTTP request and is easy for many vendors to build on/against. As far as rewriting the world, this happens to luckily not be quite true, thanks to projects like wasi-libc: https://github.com/webassembly/wasi-libc Networking is actually much more solved in WASI now than it was roughly a year ago -- threads is taking a little longer to cook (for good reasons), but async (without function coloring) is coming this year (likely in the next 3-4 months). The sandboxing abilities of WASM are near unmatched, along with it's startup time and execution speed compared to native.
In WASM will replace containers

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