[Vala] Dynamic arrays in Vala - example for newbie

[Leonti Bielski <prishelec gmail com>]

Hello!
I'm writing an application and I've come to the point where I need to
use dynamic arrays.
I tried Garray:

GLib.Array<string> test_calls; // it's declared from the start to be global

test_calls = new GLib.Array<string>(false,  false, (uint)sizeof(string));
test_calls.append_val("some string");
debug("%s", test_calls.index(0));

It gives me segmentation fault.
How do I do this properly?

I've been searching the whole day for example in Vala and couldn't find one :(
Thanks. Leonti