% readpst -o foo sent_items.pst
Opening PST file and indexes...
Hmm, that's strange, it didn't seem to do anything. I
wonder what's wrong with the file?
% cat sent_items.pst
cat: sent_items.pst: Permission denied
So readpst is not checking the result of open() and
printing an error message as it should. At least that
is my guess. The expected behaviour is to print a
message to stderr and return a nonzero status if the
file could not be read.