systemd Developer Lennart Poettering lennart@poettering.net sd_seat_get_active 3 sd_seat_get_active sd_seat_get_sessions sd_seat_can_multi_session Determine state of a specific seat #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* n_uids int sd_seat_can_multi_session const char* session 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 be passed NULL, in case only one of the parameters shall be queried. The returned string needs to be freed with the libc free3 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 free3 call after use. 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 (whith only one being active at a time). On success sd_seat_get_active() return return 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 returns a positive integer, if it fails 0. On failure, these calls return a negative errno-style error code. The sd_seat_get_active(), sd_seat_get_sessions(), and sd_seat_can_multi_session() interfaces are available as shared library, which can be compiled and linked to with the libsystemd-login pkg-config1 file. systemd1, sd-login7, sd_session_get_seat3,