fminsearch with C matlab coder ?

Referring to https://www.mathworks.com/matlabcentral/answers/161876-matlab-coder-and-fminsearch-what-implementation-strategy

I didn't understand how to define the function using presistant values, what I did is this function p=fun(x,D,y,lampda,h)

persistent D_saved;

persistent y_saved;

persistent lampda_saved;

persistent h_saved;

D_saved=D;

y_saved=y;

h_saved=h;

lampda_saved=lampda;

p=(lampda_saved*norm(h_saved-x,1))+norm((D_saved*x)-y_saved,2);

and when using fminsearch

problem.options = optimset('Display','off','TolX',ep,'TolFun',ep);

problem.solver = 'fminsearch';

problem.objective = fun(x,D,y,lampda,h);

where h, D, and y are variables and x is to be optimised when I run this I get an error "Undefined function or variable 'x'" ?