Returns the current process group for the specified PID. Use
a PID of
to get the current process group for the
current process. Will raise an exception if used on a machine that
doesn't implement getpgrp(2). If PID is omitted, returns the process
group of the current process. Note that the POSIX version of
getpgrp does not accept a PID argument, so only
is truly portable.
Portability issues: getpgrp in perlport.