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GETPGRP(2)		       System Calls Manual		      GETPGRP(2)

NAME
     getpgrp -- get process group

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     pid_t
     getpgrp(void);

     pid_t
     getpgid(pid_t pid);

DESCRIPTION
     The  process  group  of  the current process is returned by getpgrp().  The
     process group of the process identified by pid is	returned  by  getpgid().
     If pid is zero, getpgid() returns the process group of the current process.

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

RETURN VALUES
     The getpgrp() system call always succeeds.  Upon successful completion, the
     getpgid() system call returns the process group of the  specified	process;
     otherwise, it returns a value of -1 and sets errno to indicate the error.

COMPATIBILITY
     This version of getpgrp() differs from past Berkeley versions by not taking
     a	pid_t  pid  argument.	This  incompatibility  is  required  by  ISO/IEC
     9945-1:1990 ("POSIX.1").

     From the ISO/IEC 9945-1:1990 ("POSIX.1") Rationale:

     4.3BSD provides a getpgrp() system call 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 AT&T System V UNIX getpgrp() suf-
     fices, and the added complexity of the 4.3BSD getpgrp()  has  been  omitted
     from POSIX.1.  The old functionality is available from the getpgid() system
     call.

ERRORS
     The getpgid() system call will succeed unless:

     [ESRCH]		there is no process whose process ID equals pid

SEE ALSO
     getsid(2), setpgid(2), termios(4)

STANDARDS
     The  getpgrp()  system  call  is expected to conform to ISO/IEC 9945-1:1990
     ("POSIX.1").

HISTORY
     The getpgrp() system call appeared in 4.0BSD.  The getpgid() system call is
     derived from its usage in AT&T System V Release 4 UNIX.

FreeBSD ports 15.quarterly	  June 4, 1993			      GETPGRP(2)

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