TCSETSID(3)            FreeBSD Library Functions Manual            TCSETSID(3)

NAME
     tcsetsid - set session ID associated with a controlling terminal

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/types.h>
     #include <termios.h>

     int
     tcsetsid(int fd, pid_t pid);

DESCRIPTION
     The tcsetsid() function sets associates a session identified by pid with
     a controlling terminal specified by fd.

     This implementation only allows the controlling terminal to be changed by
     the session leader itself.  This implies that pid always has to be equal
     to the process ID.

     It is unsupported to associate with a terminal that already has an
     associated session.  Conversely, it is also unsupported to associate to a
     terminal when the session is already associated with a different
     terminal.

ERRORS
     If an error occurs, tcsetsid() returns -1 and the global variable errno
     is set to indicate the error, as follows:

     [EBADF]            The fd argument is not a valid file descriptor.

     [ENOTTY]           The file descriptor represented by fd is not a
                        terminal.

     [EINVAL]           The pid argument is not equal to the session ID of the
                        calling process.

     [EPERM]            The calling process is not a session leader.

     [EPERM]            The session already has an associated terminal or the
                        terminal already has an associated session.

SEE ALSO
     getsid(2), setsid(2), tcgetpgrp(3), tcgetsid(3)

HISTORY
     A tcsetsid() function first appeared in QNX.  It does not comply to any
     standard.

FreeBSD 13.1-RELEASE-p6           May 4, 2009          FreeBSD 13.1-RELEASE-p6