getpgid(2) - NetBSD Manual Pages

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GETPGRP(2)                NetBSD System Calls Manual                GETPGRP(2)


NAME

     getpgrp, getpgid -- 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 pid process is returned by getpgid().

     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.


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 System V 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() function.


ERRORS

     getpgrp() always succeeds, however getpgid() will succeed unless:

     [ESRCH]            if there is no process with a process ID equal to pid.


SEE ALSO

     setpgid(2), termios(4)


STANDARDS

     The getpgrp() function conforms to IEEE Std 1003.1-1988 (``POSIX.1'').


HISTORY

     The getpgrp() function call appeared in 4.0BSD.  The getpgid() function
     call is derived from its usage in AT&T System V.4 UNIX, and first
     appeared in NetBSD 1.3.

NetBSD 10.99                    August 11, 2002                   NetBSD 10.99