Function precover

3rd/lua-5.4.3/src/ldo.c:762–770

** Unrolls a coroutine in protected mode while there are recoverable ** errors, that is, errors inside a protected call. (Any error ** interrupts 'unroll', and this loop protects it again so it can ** continue.) Stops with a normal end (status == LUA_OK), an yield ** (status == LUA_YIELD), or an unprotected error ('findpcall' doesn't ** find a recover point). */

** find a recover point).
*/
static int precover (lua_State *L, int status) {
  CallInfo *ci;
  while (errorstatus(status) && (ci = findpcall(L)) != NULL) {
    L->ci = ci;  /* go down to recovery functions */
    setcistrecst(ci, status);  /* status to finish 'pcall' */
    status = luaD_rawrunprotected(L, unroll, NULL);
  }
  return status;
}


LUA_API int lua_resume (lua_State *L, lua_State *from, int nargs,