SD_SEAT_GET_ACTIVE(3) sd_seat_get_active SD_SEAT_GET_ACTIVE(3)NAME
sd_seat_get_active, sd_seat_get_sessions, sd_seat_can_multi_session,
sd_seat_can_tty, sd_seat_can_graphical - Determine state of a specific
seat
SYNOPSIS
#include <systemd/sd-login.h>
int sd_seat_get_active(const char* seat, char** session, uid_t* uid);
int sd_seat_get_sessions(const char* seat, char*** sessions,
uid_t** uid, unsigned int* n_uids);
int sd_seat_can_multi_session(const char* seat);
int sd_seat_can_tty(const char* seat);
int sd_seat_can_graphical(const char* seat);
DESCRIPTIONsd_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 after
use.
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
display.
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.
RETURN VALUE
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.
NOTES
The sd_seat_get_active(), sd_seat_get_sessions(),
sd_seat_can_multi_session(), sd_seat_can_tty() and
sd_seat_can_grapical() interfaces are available as a shared library,
which can be compiled and linked to with the libsystemd-login pkg-
config(1) file.
SEE ALSOsystemd(1), sd-login(3), sd_session_get_seat(3)systemd 208SD_SEAT_GET_ACTIVE(3)
