Function lua_tolstring

3rd/lua-5.4.3/src/lapi.c:399–417

LUA_API const char *lua_tolstring (lua_State *L, int idx, size_t *len) {
  TValue *o;
  lua_lock(L);
  o = index2value(L, idx);
  if (!ttisstring(o)) {
    if (!cvt2str(o)) {  /* not convertible? */
      if (len != NULL) *len = 0;
      lua_unlock(L);
      return NULL;
    }
    luaO_tostring(L, o);
    luaC_checkGC(L);
    o = index2value(L, idx);  /* previous call may reallocate the stack */
  }
  if (len != NULL)
    *len = vslen(o);
  lua_unlock(L);
  return svalue(o);
}


LUA_API lua_Unsigned lua_rawlen (lua_State *L, int idx) {