NAME¶
tcgetpgrp, tcsetpgrp - get and set terminal foreground process group
SYNOPSIS¶
#include <unistd.h>
pid_t tcgetpgrp(int fd);
int tcsetpgrp(int fd, pid_t pgrp);
DESCRIPTION¶
The function
tcgetpgrp() returns the process group ID of the foreground
process group on the terminal associated to
fd, which must be the
controlling terminal of the calling process.
The function
tcsetpgrp() makes the process group with process group ID
pgrp the foreground process group on the terminal associated to
fd, which must be the controlling terminal of the calling process, and
still be associated with its session. Moreover,
pgrp must be a
(nonempty) process group belonging to the same session as the calling process.
If
tcsetpgrp() is called by a member of a background process group in its
session, and the calling process is not blocking or ignoring
SIGTTOU, a
SIGTTOU signal is sent to all members of this background process group.
RETURN VALUE¶
When
fd refers to the controlling terminal of the calling process, the
function
tcgetpgrp() will return the foreground process group ID of
that terminal if there is one, and some value larger than 1 that is not
presently a process group ID otherwise. When
fd does not refer to the
controlling terminal of the calling process, -1 is returned, and
errno
is set appropriately.
When successful,
tcsetpgrp() returns 0. Otherwise, it returns -1, and
errno is set appropriately.
ERRORS¶
- EBADF
- fd is not a valid file descriptor.
- EINVAL
- pgrp has an unsupported value.
- ENOTTY
- The calling process does not have a controlling terminal, or it has one
but it is not described by fd, or, for tcsetpgrp(), this
controlling terminal is no longer associated with the session of the
calling process.
- EPERM
- pgrp has a supported value, but is not the process group ID of a
process in the same session as the calling process.
ATTRIBUTES¶
Multithreading (see pthreads(7))¶
The
tcgetpgrp() and
tcsetpgrp() functions are thread-safe.
POSIX.1-2001.
NOTES¶
These functions are implemented via the
TIOCGPGRP and
TIOCSPGRP
ioctls.
History¶
The ioctls appeared in 4.2BSD. The functions are POSIX inventions.
SEE ALSO¶
setpgid(2),
setsid(2),
credentials(7)
COLOPHON¶
This page is part of release 3.74 of the Linux
man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at
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