NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

TCGETPGRP(3)              Linux Programmer's Manual             TCGETPGRP(3)

NAME         top

       tcgetpgrp, tcsetpgrp - get and set terminal foreground process group

SYNOPSIS         top

       #include <unistd.h>

       pid_t tcgetpgrp(int fd);

       int tcsetpgrp(int fd, pid_t pgrp);

DESCRIPTION         top

       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         top

       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         top

       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         top

       For an explanation of the terms used in this section, see
       attributes(7).

       ┌─────────────────────────┬───────────────┬─────────┐
       │Interface                Attribute     Value   │
       ├─────────────────────────┼───────────────┼─────────┤
       │tcgetpgrp(), tcsetpgrp() │ Thread safety │ MT-Safe │
       └─────────────────────────┴───────────────┴─────────┘

CONFORMING TO         top

       POSIX.1-2001, POSIX.1-2008.

NOTES         top

       These functions are implemented via the TIOCGPGRP and TIOCSPGRP
       ioctls.

   History
       The ioctls appeared in 4.2BSD.  The functions are POSIX inventions.

SEE ALSO         top

       setpgid(2), setsid(2), credentials(7)

COLOPHON         top

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GNU                              2015-08-08                     TCGETPGRP(3)