Function luaL_getsubtable

freebsd/contrib/openzfs/module/lua/lauxlib.c:722–733

** ensure that stack[idx][fname] has a table and push that table ** into the stack */

** into the stack
*/
LUALIB_API int luaL_getsubtable (lua_State *L, int idx, const char *fname) {
  lua_getfield(L, idx, fname);
  if (lua_istable(L, -1)) return 1;  /* table already there */
  else {
    lua_pop(L, 1);  /* remove previous result */
    idx = lua_absindex(L, idx);
    lua_newtable(L);
    lua_pushvalue(L, -1);  /* copy to be left at top */
    lua_setfield(L, idx, fname);  /* assign new table to field */
    return 0;  /* false, because did not find table there */
  }
}


/*