How do I read system information in C++?

Example:  man uname:
SEE ALSO
       uname(2), getdomainname(2), gethostname(2)


Explanation of numbers:

(1): User UNIX Command
(2): Unix and C system calls
(3): C Library routines
(4): Special file names
(5): File formats
(6):
(7):
(8): System admin commands