Section 3 of the man pages has the Linux Programmer's manual. So you can find the man page specifis to the C program function "printf" as opposed to the Bash "printf":
man 3 printf
go to the directory to browse *all* of the Programming manual:
cd /usr/share/man/man3
ls | less
and here's some great free reading online:
http://catb.org/~esr/writings/taoup/html/
http://techbooksforfree.com/linux.shtml
http://stommel.tamu.edu/~baum/programming.html#both
I also wrote a couple of Bash shell scripts, which I post at:
http://hackersnest.modblog.com
in my clumsy, still-new attempt to give back to the Linux community. The scripts there you may find helpful include "site2book", which is a small mirroring utility for getting an online book and saving it as a .tar..gz file for portable offline reading, and "411" which scans your system for documentation in whatever form exists for whatever file, program, or concept you give it. They're both beta and kludgey, but if you find them unusable you can re-think them or come up with something better!