xref: /freebsd/lib/libc/gen/tcsetsid.3 (revision 8e95079e175854b84e57c521b34b4b52f7ae9cb1)
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25.Dd November 28, 2022
26.Dt TCSETSID 3
27.Os
28.Sh NAME
29.Nm tcsetsid
30.Nd set session ID associated with a controlling terminal
31.Sh LIBRARY
32.Lb libc
33.Sh SYNOPSIS
34.In termios.h
35.Ft int
36.Fn tcsetsid "int fd" "pid_t pid"
37.Sh DESCRIPTION
38The
39.Fn tcsetsid
40function sets associates a session identified by
41.Fa pid
42with a controlling terminal specified by
43.Fa fd .
44.Pp
45This implementation only allows the controlling terminal to be changed
46by the session leader itself.
47This implies that
48.Fa pid
49always has to be equal to the process ID.
50.Pp
51It is unsupported to associate with a terminal that already has an
52associated session.
53Conversely, it is also unsupported to associate to a terminal when
54the session is already associated with a different terminal.
55.Sh ERRORS
56If an error occurs,
57.Fn tcsetsid
58returns -1 and the global variable
59.Va errno
60is set to indicate the error, as follows:
61.Bl -tag -width Er
62.It Bq Er EBADF
63The
64.Fa fd
65argument is not a valid file descriptor.
66.It Bq Er ENOTTY
67The file descriptor represented by
68.Fa fd
69is not a terminal.
70.It Bq Er EINVAL
71The
72.Fa pid
73argument is not equal to the session ID of the calling process.
74.It Bq Er EPERM
75The calling process is not a session leader.
76.It Bq Er EPERM
77The session already has an associated terminal or the terminal already
78has an associated session.
79.El
80.Sh SEE ALSO
81.Xr getsid 2 ,
82.Xr setsid 2 ,
83.Xr tcgetpgrp 3 ,
84.Xr tcgetsid 3
85.Sh HISTORY
86A
87.Fn tcsetsid
88function first appeared in QNX.
89It does not comply to any standard.
90