How to implement a function call/return in simulink ?

I have some requirement:

if(...)
Put_Val(1)  /*Function call to a sub function inside a c file*/
else
return(NOT_DEFINED)

How to implement it in simulink ?

I tried using function call sub system.But couldn't work it out.

Answer 1

[Azzi Abdelmalek]

Have you tried Interpreted Matlab Function block

[Ramesh Vukyam]

Thank you for your help Azzi. The Interpreted Matlab function block applies the specified MATLAB function or expression to the input. Here what I have is my own c function.I suppose it will not help in this case.

[Azzi Abdelmalek]

If you are using a c file, maybe you need s-function block