Safety Locks for Sliding Glass Doors?

There seems to be a bunch of options:

http://www.mypreciouskid.com/window-wedge.html

http://www.kidsafeinc.com/product/8702/Sliding_Door_Flip_...

http://www.thedoorguardian.com/product.aspx?prodID=PatioD...

When my children were young, they were little escape artists. They actually snuck outside at 3 & 4 to play barefoot in the snow; I found out the next morning -footprint evidence. This excursion was before home alarm systems were standard. I found sliding door screw clips at the hardware store. If you cannot find the clips it would be simple to drill a small hole in the upper track of the sliding glass door and slip a small nail in the track.

We also have a sliding glass door and a toddler who can unlock and open it. We got pretty worried so we went to Home Depot and bought a metal lock, that looks like a tiny clamp with a screw, to put at the top of the door. He can't get the door open at all with this lock on it. It was very cheap and I think they had a few different options. You could also probably get the same thing at Lowes. Hope this helps.

Years ago when I had a sliding glass door, for security purposes, I used a broomstick or something like that, cut to size to lay in the sliding tray.

If you tried to open the door, it would not slide because of the barrier.

I know that is nothing fancy but it worked for me and I felt a little safer. I was single at the time on a first floor apartment.