Why exit code 141 with grep -q?

Question

Can someone explain why I get exit code 141 from the below?

#!/usr/bin/bash

set -o pipefail

zfs list | grep tank
echo a ${PIPESTATUS[@]}

zfs list | grep          


        

Answer 1

I'm not familiar with zfs list, but I guess it complains about its standard output being closed - grep -q exits immediately when a match is found, unlike grep.