Checking line segment intersection

Hi Guys

If I have two lines whose coordinates are defined by

L1: (x1,y1) (x2,y2)
L2: (x3,y3) (x4,y4)

What do I need to do to see if they intersect?

I'm pretty sure that there is at least one line intersection algorithm in the code archives...

D'oh! Of course.

Thanks for pointing that out!