reference and resources:

https://wiki.xxiivv.com/site/plan9_c.html
http://doc.cat-v.org/plan_9/programming/c_programming_in_plan_9
http://blog.postnix.pw/2018/09/21/0/
http://sdf.org/?tutorials/Plan_9_C
https://9fans.github.io/plan9port/man/man3/intro.html
https://github.com/nspool/hello-plan9

general:

http://crasseux.com/books/ctutorial/index.html
https://beej.us/guide/bgc/html/

archive:

https://archive.ph/VCpoC

ideas of stuff to do?:

https://www.roguebasin.com/index.php?title=How_to_Write_a_Roguelike_in_15_Steps