tcgetpgrp

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 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 │ 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
       This page is part of release 5.13 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
       https://www.kernel.org/doc/man-pages/.



GNU                                2021-03-22                       TCGETPGRP(3)