I noticed typing in shell like

man printf

shows a man page entry. Usually there are man pages for each command. I mean man pages are supposed to be for APIs and external interfaces (like g++, etc). How did the internals of say the c standard library functions end up there (who did it?)?

I also want to know the whole business of man page. How to create man pages for your application and how to register(or something???) to the man page database of the system?

You should take a look at this link, You'll find manpages has 8 sections

http://linuxmanpages.com/

The link that you gave is a directory containing all the man pages whereas my question was how do you install man pages.

When stating a question, it should be prominent in your postings not included with a line like:

I also want to know the whole business of man page

Which indicates that this is the secondary question not the primary.

About your question check out his link

http://linux.omnipotent.net/article.php?article_id=12493&page=1

Which I arrived at by typing in firefox "linux creating man pages"