> With an uninitialised pointer, you roll the dice and luck out on a valid address you can trash with your input.
> A null pointer is a guaranteed segmentation fault whenever you try to do anything with it.

Thanks for your input!
So the problem is, that I use the NULL pointer as input for my function (or like you said "try to do anything with it")?
That looks like quite the predicament for me. By assignment of my prof the append function has to use a pointer as its input (so basically the starting point of the list).
I don't wanna create the first list element outside of the function and create all the other elements inside of the function. Any ideas how I could solve this?

> Use the debugger.
> The debugger will catch the segfault and point you at the actual line of code causing the trouble.

Alright! I will this out