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() suffices, 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.

Debian                                            June 4, 1993                                        GETPGRP(2)