Function luaT_getvarargs

third-party/lua-5.5.0/src/ltm.c:338–363

** Get 'wanted' vararg arguments and put them in 'where'. 'vatab' is ** the register of the vararg table or -1 if there is no vararg table. */

** the register of the vararg table or -1 if there is no vararg table.
*/
void luaT_getvarargs (lua_State *L, CallInfo *ci, StkId where, int wanted,
                                    int vatab) {
  Table *h = (vatab < 0) ? NULL : hvalue(s2v(ci->func.p + vatab + 1));
  int nargs = getnumargs(L, ci, h);  /* number of available vararg args. */
  int i, touse;  /* 'touse' is minimum between 'wanted' and 'nargs' */
  if (wanted < 0) {
    touse = wanted = nargs;  /* get all extra arguments available */
    checkstackp(L, nargs, where);  /* ensure stack space */
    L->top.p = where + nargs;  /* next instruction will need top */
  }
  else
    touse = (nargs > wanted) ? wanted : nargs;
  if (h == NULL) {  /* no vararg table? */
    for (i = 0; i < touse; i++)  /* get vararg values from the stack */
      setobjs2s(L, where + i, ci->func.p - nargs + i);
  }
  else {  /* get vararg values from vararg table */
    for (i = 0; i < touse; i++) {
      lu_byte tag = luaH_getint(h, i + 1, s2v(where + i));
      if (tagisempty(tag))
       setnilvalue(s2v(where + i));
    }
  }
  for (; i < wanted; i++)   /* complete required results with nil */
    setnilvalue(s2v(where + i));
}