"sem -j0" wierdness

[Achim Gratz]

Consider the following transcript  (from Cygwin):

(1020)~ > sem -j0 echo bla && sem --wait
parallel: Warning: Starting 143 processes took > 2 sec.
Consider adjusting -j. Press CTRL-C to stop.
parallel: Warning: Only enough available processes to run 255 jobs in
parallel. Raising ulimit -u or /etc/security/limits.conf
or /proc/sys/kernel/pid_max may help.
parallel: Warning: Cannot spawn any jobs. Raising ulimit -u or
/etc/security/limits.conf
or /proc/sys/kernel/pid_max may help.
(1021)~ > sem -j+0 echo bla && sem --wait
bla

Why would starting sem with a "-j0" argument start more than a single
process in the above?  Given that "-j0" doesn't really make sense for sem,
should it perhaps just refuse to take that argument or treat it as a NOP?


Regards,
Achim.