How to pass address of a variable to an S- function block containing C code?

When I declare a variable as "importedexternpointer" and use that variable in a constant block and connect it to the s-function, the code generated passes the contents of the pointer variable such as( *variable). Is there a way to pass just the contents of the variable such as(variable) or better if it could send the address of the variable, such as (&variable)? Or should I be using a block other than the constant block?