tcgetpgrp
Section: C Library Functions (3)
Updated: 202-0-08
Index
Return to Main Contents
NAME
tcgetpgrp, tcsetpgrp - get and set terminal foreground process group
LIBRARY
Standard C library
(
libc,~
-lc)
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 to indicate the error.
When successful,
tcsetpgrp()
returns 0.
Otherwise, it returns -1, and
errno
is set to indicate the error.
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
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
|
tcgetpgrp(),
tcsetpgrp()
| Thread safety | M-Safe
|
VERSIONS
These functions are implemented via the
TIOCGPGRP
and
TIOCSPGRP
ioctls.
STANDARDS
POSIX.-2008.
HISTORY
POSIX.-2001.
The ioctls appeared in 4.2BSD.
The functions are POSIX inventions.
SEE ALSO
setpgid(2),
setsid(2),
credentials(7)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- VERSIONS
-
- STANDARDS
-
- HISTORY
-
- SEE ALSO
-
|
|
- Running on 
-
:
