sd_seat_get_active() may be used to determine which session is
currently active on a seat, if there is any. Returns the session
identifier and the user identifier of the Unix user the session is
belonging to. Either the session or the user identifier parameter can
be passed NULL, in case only one of the parameters shall be queried.
The returned string needs to be freed with the libc free(3) call
sd_seat_get_sessions() may be used to determine all sessions on the
specified seat. Returns two arrays, one (NULL terminated) with the
session identifiers of the sessions and one with the user identifiers
of the Unix users the sessions belong to. An additional parameter may
be used to return the number of entries in the latter array. The two
arrays and the latter parameter may be passed as NULL in case these
values need not to be determined. The arrays and the strings
referenced by them need to be freed with the libc free(3) call after
use. Note that instead of an empty array NULL may be returned and
should be considered equivalent to an empty array.
sd_seat_can_multi_session() may be used to determine whether a
specific seat is capable of multi-session, i.e. allows multiple login
sessions in parallel (with only one being active at a time).
sd_seat_can_tty() may be used to determine whether a specific seat
provides TTY functionality, i.e. is useful as a text console.
sd_seat_can_graphical() may be used to determine whether a specific
seat provides graphics functionality, i.e. is useful as a graphics
If the seat parameter of any of these functions is passed as NULL,
the operation is executed for the seat of the session of the calling
process, if there is any.
On success, sd_seat_get_active() returns 0 or a positive integer. On
success, sd_seat_get_sessions() returns the number of entries in the
session identifier array. If the test succeeds,
sd_seat_can_multi_session, sd_seat_can_tty and sd_seat_can_graphical
return a positive integer, if it fails 0. On failure, these calls
return a negative errno-style error code.
Returned errors may indicate the following problems:
The given field is not specified for the described seat.
The specified seat is unknown.
An input parameter was invalid (out of range, or NULL, where that
is not accepted).
Memory allocation failed.
The sd_seat_get_active(), sd_seat_get_sessions(),
sd_seat_can_multi_session(), sd_seat_can_tty() and
sd_seat_can_graphical() interfaces are available as a shared library,
which can be compiled and linked to with the libsystemd pkg-config(1)
This page is part of the systemd (systemd system and service manager)
project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2017-03-13. If you dis‐
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you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
systemd 233 SD_SEAT_GET_ACTIVE(3)