pid_t
getpgrp(void)
pid_t
getpgid(pid_t pid)
).
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.
)
always succeeds, however
getpgid()
will succeed unless:
ESRCH]pid.
)
function conforms to
IEEE Std 1003.1-1988 (``POSIX.1'') .
)
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
NetBSD1.3.
)
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()
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.