[pjmlp]

For those that care about security in C, even those functions are not the way to go, rather something like https://github.com/antirez/sds.

This is something that the book fails to teach, as it also has no mentions of modern static analysers practices, naturally given the book's age.

So at the end we get yet another C newbie writing future CVEs.

[saagarjha]

Those are both modern additions to the language, the latter of which I would say is a necessary part of any formal C education (I always mention "K&R with supplements" as the go-to way to learn C). Thus, I wouldn't call it "outdated" but maybe "incomplete"; all the information in the book is fairly up-to-date-but it is missing things that modern C programmers should know.