Standard Error

What package does this fall under? There are no man pages for it. Is it safe to assume documentation for libc?

It's part of all stdio libraries. And I have manpages for it. Are you sure that you don't? If it could be that your man files are erroneous in some way, try checking the manpages for setbuf(3), setbuffer(3) or setlinebuf(3) as well.

I recently installed glibc doc but it only came with HTML files and some man pages dealing with threads. The functions discussed here weren't included in that package.

Thanks for the tip. The man page explains it well. Cheers!