4.4BSD/usr/share/man/cat2/getpgrp.0

GETPGRP(2)                  BSD Programmer's Manual                 GETPGRP(2)

NNAAMMEE
     ggeettppggrrpp - get process group

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<uunniissttdd..hh>>

     _p_i_d___t
     ggeettppggrrpp(_v_o_i_d);

DDEESSCCRRIIPPTTIIOONN
     The process group of the current process is returned by ggeettppggrrpp().

     Process groups are used for distribution of signals, and by terminals to
     arbitrate requests for their input: processes that have the same process
     group as the terminal are foreground and may read, while others will
     block with a signal if they attempt to read.

     This call is thus used by programs such as csh(1) to create process
     groups in implementing job control.  The ttccggeettppggrrpp() and ttccsseettppggrrpp()
     calls are used to get/set the process group of the control terminal.

SSEEEE AALLSSOO
     setpgid(2),  termios(4)

HHIISSTTOORRYY
     The ggeettppggrrpp function call appeared in 4.0BSD.

SSTTAANNDDAARRDDSS
     The ggeettppggrrpp() function conforms to IEEE Std 1003.1-1988 (``POSIX'').

CCOOMMPPAATTAABBIILLIITTYY
     This version of ggeettppggrrpp() differs from past Berkeley versions by not tak-
     ing a _p_i_d___t _p_i_d argument.  This incompatibility is required by IEEE
     Std1003.1-1988 (``POSIX'').

     From the IEEE Std1003.1-1988 (``POSIX'') Rationale:

     4.3BSD provides a ggeettppggrrpp() function that returns the process group ID
     for a specified process.  Although this function is used to support job
     control, all known job-control shells always specify the calling process
     with this function.  Thus, the simpler System V ggeettppggrrpp() suffices, and
     the added complexity of the 4.3BSD ggeettppggrrpp() has been omitted from
     POSIX.1.

4.2 Berkeley Distribution        June 4, 1993                                1