Function opencheck

extlibs/lua/src/liolib.c:249–254

static void opencheck (lua_State *L, const char *fname, const char *mode) {
  LStream *p = newfile(L);
  p->f = fopen(fname, mode);
  if (p->f == NULL)
    luaL_error(L, "cannot open file '%s' (%s)", fname, strerror(errno));
}


static int io_open (lua_State *L) {