Initialize the state vectors of this C MEX S-function
#define MDL_START void mdlStart(SimStruct *S)
The Simulink® engine invokes this optional method at the beginning of a simulation. The method performs initialization activities that this S-function requires only once, such as allocating memory, setting up user data, or initializing states.
If your S-function resides in an enabled subsystem and needs to reinitialize its states every whenever the subsystem is enabled, use mdlInitializeConditions to initialize the state values, instead of mdlStart.