This post is dedicated to the C language.

C11 standard

C11 draft

http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf

thread in C

TinyCThread - threads in C

https://tinycthread.github.io/

More C resources

Learn C The Hard Way

http://c.learncodethehardway.org/book/

Program writen in C

https://github.com/git/git