Provided by: systemtap-doc_2.9-2ubuntu2_all 

NAME
function::pgrp - Returns the process group ID of the current process
SYNOPSIS
pgrp:long()
ARGUMENTS
None
DESCRIPTION
This function returns the process group ID of the current process.
SEE ALSO
tapset::context(3stap)
SystemTap Tapset Reference April 2016 FUNCTION::PGRP(3stap)