wait -n -p var assigns a random number to var if there are no jobs

[Oğuz]

See:

$ echo $BASH_VERSION
5.1.0(1)-release
$
$ jobs
$ wait -n -p var
$ echo $var $?
66390280 127

If it left `var' unset that would be way more helpful to determine whether
one of the jobs exited with 127 or all the jobs were waited for and none
left.

Oğuz