failures=
failure() {
	echo "Error at line $1" >&2
	failures=x$failures
}

T=$(mktemp -d ${TMPDIR:-/tmp}/sh-test.XXXXXX)
trap 'rm -rf $T' 0
cd $T || exit 3
mkfifo fifo1
for i in 1 2 3 4 5 6 7 8 9 10; do
	exit $i 4<fifo1 &
done
exec 3>fifo1
wait || failure $LINENO
(${SH} -c echo >&3) 2>/dev/null && failure $LINENO
wait || failure $LINENO

test -z "$failures"