Iâ€™m little surprised to find that Ubuntu Linux skips development man pages by default. A quick search using apt-cache pointed out to manpages-dev package. It includes manual pages about using GNU/Linux for development.
Install development man pages
Use apt-get command:
$ sudo apt-get install manpages-dev
To view library calls (functions within program libraries), enter:
$ man 3 function-name
$ man 3 putc