Ok, your comment already did shed some light. And looking closely, the [value] code actually uses *x_floatstar ... so let me get this straight, that makes it a pointer then, so it works. Now, I'm also using the same thing to create an array of values, that can be set with something like x->x_fval[i]. This is where things get confusing to me. Now, in an earlier version, this was working and initialized as **x_fval which then it seems it is a pointer to the array of values? 

In the end, the question would be how to initialize a variable that can take the pointer correctly. Was the last compilable code from https://github.com/porres/pd-else/blob/cd1406cff28baf1eb056d1500fb0d62694171306/Code_source/Compiled/control/var.c completely correct? I guess I got lucky then and when tried to fix what wasn't broken I just ruined it. And the bugs I was trying to fix were unrelated.

Another good question would be simple online courses that could help me understand things a little better :)

thanks