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 │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

VERSIONS

       These functions are implemented via the TIOCGPGRP and TIOCSPGRP ioctls.

STANDARDS

       POSIX.1-2008.

HISTORY

       POSIX.1-2001.

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

SEE ALSO

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

Linux man-pages 6.7                                2023-10-31                                       tcgetpgrp(3)