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GETPGRP(2)		    BSD	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 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() call	always succeeds.  Upon successful completion, the
     getpgid() call returns the	process	group of the specified process;	other-
     wise, it returns a	value of -1 and	sets errno to indicate the error.

ERRORS
     getpgid() will succeed unless:

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

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

HISTORY
     The getpgrp() function call appeared in 4.0BSD.  The getpgid() function
     call is derived from its usage in System V	Release	4.

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

COMPATIBILITY
     This version of getpgrp() differs from past Berkeley versions by not tak-
     ing 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() 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 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()
     function.

BSD				 June 4, 1993				   BSD

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | HISTORY | STANDARDS | COMPATIBILITY

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