Function os_date

depends/lua/src/loslib.c:283–322

static int os_date (lua_State *L) {
  size_t slen;
  const char *s = luaL_optlstring(L, 1, "%c", &slen);
  time_t t = luaL_opt(L, l_checktime, 2, time(NULL));
  const char *se = s + slen;  /* 's' end */
  struct tm tmr, *stm;
  if (*s == '!') {  /* UTC? */
    stm = l_gmtime(&t, &tmr);
    s++;  /* skip '!' */
  }
  else
    stm = l_localtime(&t, &tmr);
  if (stm == NULL)  /* invalid date? */
    return luaL_error(L,
                 "time result cannot be represented in this installation");
  if (strcmp(s, "*t") == 0) {
    lua_createtable(L, 0, 9);  /* 9 = number of fields */
    setallfields(L, stm);
  }
  else {
    char cc[4];  /* buffer for individual conversion specifiers */
    luaL_Buffer b;
    cc[0] = '%';
    luaL_buffinit(L, &b);
    while (s < se) {
      if (*s != '%')  /* not a conversion specifier? */
        luaL_addchar(&b, *s++);
      else {
        size_t reslen;
        char *buff = luaL_prepbuffsize(&b, SIZETIMEFMT);
        s++;  /* skip '%' */
        s = checkoption(L, s, se - s, cc + 1);  /* copy specifier to 'cc' */
        reslen = strftime(buff, SIZETIMEFMT, cc, stm);
        luaL_addsize(&b, reslen);
      }
    }
    luaL_pushresult(&b);
  }
  return 1;
}


static int os_time (lua_State *L) {