Shows all sync packages if stdin is empty with -

[AladW]

printf '' | expac -S '%n' - | wc -l
8814

Compare to pacman --print:

% printf '' | pacman -Sddp -
error: argument '-' specified with empty stdin

A workaround is expac -S '%n' - '' or xargs -r expac -S '%n' -, assuming the user expects this behavior.

[falconindy]

Fix queued, will hopefully be able to push tonight.