tree cd813fd944ccb6226be2fd2ba24a27b04d6753c0
parent 70e58a142af3c23266e99446123a6105fe96b8be
author Haoming Zhang <zhm1993zhm@gmail.com> 1500676626 -0700
committer Haoming Zhang <zhm1993zhm@gmail.com> 1500676626 -0700

add err check