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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_GET_SEATS(3) sd_get_seats 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 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.
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.
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.
sd_get_machine_names() was added in version 203.
systemd(1), sd-login(3), sd_session_get_seat(3)
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
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-08-11.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 258~rc2 SD_GET_SEATS(3)
Pages that refer to this page: procps_misc(3), sd-login(3), sd_login_monitor_new(3), systemd.directives(7), systemd.index(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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