Look closely at how your door latch actually works.
The latch on a gullwing door will work exactly as it does to release and close a slider. Pull it up and to the left to open, down and to the right to close.
Except that on the front part of the sliding door the latch slides into a bracket on the pillar before it will latch, on a gull wing the door is going to swing straight out so it won't be able to work