How can I generate embedded C code from Simulink with get/set functions?

I'm generating code from a Simulink model for a software module, and in order to conform to the architecture there are predefined interfaces it must implement. The problem is, I can't find a good way to generate code that implements set/get for a Data Store Memory. For example, say I want to generate code similar to this:

foo.c

double A
boolean Compare (double In1) { return (In1 <= A); }
void setA (double new_A) { if (new_A > 0) { A = new_A; } }
void getA (double *ret_A) { *ret_A = A; }

The best solution I've got this far is an export-function model where I define set and get as Simulink functions (see attachment), but that is not practical when I have multiple variables that I want to set/get individually, and forces me to wrap the module functionality in a function-call subsystem. Using one of the "export" storage classes would be unsafe since it doesn't allow me to validate the input in a set().

Is there an option I'm missing that allows me to do this? If not, what would be a good starting point? My next step is trying to create a custom storage class, but set/get is so commonplace in code that I'm assuming the option is somewhere and I missed it.