Plotting graphs on a PC, from a 'C' program

[CIZIN]

After reading some of the replies that I got
following my last request, I'm posting this new
one to be more concrete:
I am looking for a 'C' language toolkit to plot    
some simple graphs after collecting data using
a P.C. with a 'C' program. "Halo" and other
software packages are very good, but they don't
provide ready plotting functions, only the functions
to build plots.

Thanks,            
		Miguel Cizin
		whuts!mig