u have to declare and initialise your struct first (in the main or where ever u wish)

int main()
{
//declare your struct
struct my_type{
int num;
char letter;
}

//put value to your struct
struct my_type my_var{1,'c'};

// here is how u parse it to a function
my_function(my_var);
}

//this is your fucntion prototype
void my_function(struct my_type myvar)
{
//..... do something.....
}

note: the above is for standard c though