Requesting Superuser

[Jesse Phillips]

As a Linux programmer it can be important to have a program run with 
superuser privileges. I am trying to figure out the best way to either 
become a super user by asking for a password, or simply checking if it is 
run as a superuser.

I have been looking at how to do this in C and found information on suser
() which seems to be for FreeBSD.
http://www.gsp.com/cgi-bin/man.cgi?section=9&topic=suser

I was also reading some stuff on secure programming which said not to use 
system() because it invokes the shell, that's fine but is it really a 
problem?
http://www.onlamp.com/pub/a/onlamp/excerpt/PUIS3_chap16/index1.html

Any good links or search queries would be great.

Thanks,
Jesse Phillips