I am looking to expand from console to graphical applications programming on Linux. I understand that SDL is commonly used for games, and GTK+ is commonly used for desktop apps, but it seems SDL can do most of (if not all) the same stuff as GTK+.

Would it be worthwhile to learn both? I would like to eventually get into games programming (still on Linux), so I figure I will have to learn SDL anyways. Should I just skip the GTK+?