I find the source code of the Netsurf browser really beautiful:

- https://netsurf-browser.org/

- https://source.netsurf-browser.org/netsurf.git/tree/

Including the sub projects, for instance:

- https://source.netsurf-browser.org/libcss.git/tree/

- https://source.netsurf-browser.org/libdom.git/tree/

It feels immediately obvious and understandable, which is quite impressive for a browser. Everything is well documented, well separated, the code is clean and seems simple, functions are small, etc. I am really impressed. I'd want to work on such code. I have never worked on it though, and I am not connected in any way to this project.

Very well written code indeed. Thanks for the links. They could make error management less bug prone by using goto, but it's definitely high quality C code nonetheless.

The sqlite codebase is well-known for being a large, well-written C codebase:

https://github.com/sqlite/sqlite

The tests in particular are very impressive.

Some other notable C codebases: Redis, LuaJIT, FreeBSD, Memcached -->

https://github.com/antirez/redis

https://github.com/LuaDist/luajit

https://github.com/freebsd/freebsd

https://github.com/memcached/memcached

PostgreSQL’s source code is also really good. https://git.postgresql.org/gitweb/?p=postgresql.git;a=tree

Varnish and the Linux kernel should be in that list as well I think.

Nice! Here are the links:

Varnish --> https://github.com/varnishcache/varnish-cache

Linux Kernel --> https://github.com/torvalds/linux

I recommend git source code which was pretty neat last time i checked.

recently I started working on a module for nginx and have developed a full-blown crush on the module loader and its relationship with core functionality. haven't seen anything else quite like it, in C, that is. major newb talkin'

also plan9, its nice to read some kernel code that hasn't been tortured by practical requirements for decades.

The core Linux kernel is well-known and mostly well-written C.

I'd say "advanced" C, not necessarily "well-written" C. There's certainly a lot of C in it, and I'd bet it's the largest open source C codebase.

They go beyond C, it's actually C + GCC extensions. The only reason clang can compile it (in some configurations) is that they painstakingly implemented each of the GCC extensions the kernel uses (and when they were almost done, the kernel started requiring a few more).