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TCGETPGRP(3)               Linux Programmer's Manual              TCGETPGRP(3)
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  con-
       trolling 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 SIGT-
       TOU, 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
       For   an   explanation   of   the  terms  used  in  this  section,  see
       attributes(7).
       +-------------------------+---------------+---------+
       |Interface                | Attribute     | Value   |
       +-------------------------+---------------+---------+
       |tcgetpgrp(), tcsetpgrp() | Thread safety | MT-Safe |
       +-------------------------+---------------+---------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.
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
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       latest    version    of    this    page,    can     be     found     at
       https://www.kernel.org/doc/man-pages/.
GNU                               2015-08-08                      TCGETPGRP(3)