You are using it correctly in Linux. To get in what section a command exists, use whatis
.
$ whatis printf
printf (1) - format and print data
printf (3) - formatted output conversion
The syntax for accessing the non-default manual section varies between different man implementations. On Solaris, for example, the syntax for reading printf(3) is:
man -s 3c printf
On Linux and BSD derivatives the same invocation would be:
man 3 printf
which searches for printf in section 3 of the man pages.