How to write Micro-controller port function and port number in C code inside MATLAB function block?

I am trying to write C code into MATLAB function block and generate code using Embedded coder. My function blocks contain some I/O ports functions (i.e. palreadPad(PORT_G, Led_D13))and port identifier(i.e. PORT_G) for a micro controller. When I tried to generate code, MATLAB is showing error message like "Undefined function or variable 'PORT_G'". I need to generate code with these port function and port number in order to run micro controller. I don't want to define the function here because it is a built in function for micro controller. I don't want to set the variable as well (i.e PORT_G=0). How can I avoid the errors and generate code from Embedded coder?