Missing 'man' entries after upgrade Having upgraded from Snow Leopard to Mountain Lion a few days ago, I find that most of the 'man' entries from section 3 (programming functions) are missing.  For example:

phillip-millss-macbook-pro:etc phil$ man fopen
No manual entry for fopen


Exploring with the terminal shows me that all that remains in man3 directories within the 'man' search path are things related to Perl.

Is there something extra that I should be installing to get the reference information back?
You can set an environmental variable called MANPATH that will tell the "man" command where to look for the man pages. I see my mac 10.12.6 (Sierra) does not have that variable set.  According to "man man"  output, it uses /etc/man.conf to know where the directories are. You can add missing paths into that file.  That file may be overwritten by an mac os x update, so you may have to do it again.  To find your missing man3 files, which are probably still on your disk, try "locate \*man3"  and it should list every directory with a man3 folder in it.
Boyd