How to extract two signals from s-function block,knowing that one of them is being generated inside a For loop ?

Hello everyone, I have an S-function block and I want to extract two signals from it.the problem is that one of the two signals outputs a result of an optimisation problem [1X1] and the other signal is built during simulation with For loop with size (p,1) . How can I extract both signals during simulation.?....thanks in advance.

Note: there is no problem to extract the first signal alone,but the problem appears when trying to extract both of them,an error shows up saying that call during flag =3 must be a real vector of length 2

U % first output signal sol.of optimisation problem.[1X1]
Y_ref % second signal generated inside a for loop with size (p,1)
sys=[U;Yref]%output of S-function ===>   an error shows up saying that call  during flag =3 must be a real vector of length 2