How to use GtkTreeSortable.

[Johan <jo_ni telia com>]

Hello,
I have created a tree store to list files and need to
write my own function to sort the filenames in order
by size. I have read the api for GtkTreeSortable, but
it doesn't explain very well how to do this.

How can I use GtkTreeSortable to sort my column?

Thank you.

/Johan