GTK Curves

[Matias Torres <torresmat gmail com>]

hello,

i'm trying to make a curve based on some values passing a float array to 
a GtkCurve:
   gtk_curve_set_vector ( GTK_CURVE (income_curve), length, array)

This results in well.. not a curve, but a number of straight lines like 
this:

4                     ____________
3
2               ____
1        ____

(hope you understand, i just don't know how to explain it let's say i'm 
looking for a continuous curve)

Changing the curve type does not help at all (segmentation fault).

Do you know how to make it work? or.. Do you know some other library 
that let's me draw a curve based on a limited number of floats?

Thanks in advance. Matias