oracular (3) sd_get_uids.3.gz

NAME

       sd_get_seats, sd_get_sessions, sd_get_uids, sd_get_machine_names - Determine available seats, sessions,
       logged in users and virtual machines/containers

SYNOPSIS

       #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);

DESCRIPTION

       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 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.

       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.

RETURN VALUE

       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.

   Errors
       Returned errors may indicate the following problems:

       -ENOMEM
           Memory allocation failed.

NOTES

       Functions described here are available as a shared library, which can be compiled against and linked to
       with the libsystemd pkg-config(1) file.

       The code described here uses getenv(3), which is declared to be not multi-thread-safe. This means that
       the code calling the functions described here must not call setenv(3) from a parallel thread. It is
       recommended to only do calls to setenv() from an early phase of the program when no other threads have
       been started.

HISTORY

       sd_get_machine_names() was added in version 203.

SEE ALSO

       systemd(1), sd-login(3), sd_session_get_seat(3)