systemd sd_get_seats 3 sd_get_seats sd_get_sessions sd_get_uids sd_get_machine_names Determine available seats, sessions, logged in users and virtual machines/containers #include <systemd/sd-login.h> int sd_get_seats char ***seats int sd_get_sessions char ***sessions int sd_get_uids uid_t **users int sd_get_machine_names char ***machines sd_get_seats() may be used to determine all currently available local seats. Returns the number of seat identifiers and if the input pointer is non-NULL, a NULL-terminated array of seat identifiers is stored at the address. The returned array and all strings it references need to be freed with the libc free3 call after use. Note that instead of an empty array NULL may be returned and should be considered equivalent to an empty array. Similarly, sd_get_sessions() may be used to determine all current login sessions. Similarly, sd_get_uids() may be used to determine all Unix users who currently have login sessions. Similarly, sd_get_machine_names() may be used to determine all current virtual machines and containers on the system. Note that the returned lists are not sorted and in an undefined order. On success, sd_get_seats(), sd_get_sessions(), sd_get_uids() and sd_get_machine_names() return the number of entries in the arrays. On failure, these calls return a negative errno-style error code. Returned errors may indicate the following problems: -ENOMEM Memory allocation failed. sd_get_machine_names() was added in version 203. systemd1 sd-login3 sd_session_get_seat3