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  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 mem‐
       bers of this background process group.

RETURN VALUE
       When fd refers to the controlling terminal of the calling process,  the  function  tcgetp‐
       grp()  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 appro‐
       priately.

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.

CONFORMING TO
       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 http://www.kernel.org/doc/man-pages/.



GNU                                         2014-01-13                               TCGETPGRP(3)