I was doing it just for testing purposes, though here's the code using the function:
// In function main
RPGItem* testItem;
testItem.type = 2;
testItem.name = testStr;
test(&testItem);
and the struct so far:
typedef struct RPGItem
{
var type;
int cellsX;
int cellsY;
BMAP* bmap;
STRING* name;
} RPGItem;
Edit: this is the first time I'm trying to use Lite-C so it wouldn't surprise me if I missed something

Edit 2: I tried using a pointer-to-a-pointer of an integer instead, and it worked, so I'm probably just missing something

Edit 3

: Tried this and it does work:
void test(RPGItem** _temp)
{
(**_temp).type = 2;
}