NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON

SD_ID128_GET_MACHINE(3)     sd_id128_get_machine     SD_ID128_GET_MACHINE(3)

NAME         top

       sd_id128_get_machine, sd_id128_get_boot - Retrieve 128-bit IDs

SYNOPSIS         top

       #include <systemd/sd-id128.h>

       int sd_id128_get_machine(sd_id128_t *ret);

       int sd_id128_get_boot(sd_id128_t *ret);

DESCRIPTION         top

       sd_id128_get_machine() returns the machine ID of the executing host.
       This reads and parses the machine-id(5) file. This function caches
       the machine ID internally to make retrieving the machine ID a cheap
       operation.

       sd_id128_get_boot() returns the boot ID of the executing kernel. This
       reads and parses the /proc/sys/kernel/random/boot_id file exposed by
       the kernel. It is randomly generated early at boot and is unique for
       every running kernel instance. See random(4) for more information.
       This function also internally caches the returned ID to make this
       call a cheap operation.

       Note that sd_id128_get_boot() always returns a UUID v4 compatible ID.
       sd_id128_get_machine() will also return a UUID v4-compatible ID on
       new installations but might not on older. It is possible to convert
       the machine ID into a UUID v4-compatible one. For more information,
       see machine-id(5).

       For more information about the "sd_id128_t" type see sd-id128(3).

RETURN VALUE         top

       The two calls return 0 on success (in which case ret is filled in),
       or a negative errno-style error code.

NOTES         top

       The sd_id128_get_machine() and sd_id128_get_boot() interfaces are
       available as a shared library, which can be compiled and linked to
       with the "libsystemd" pkg-config(1) file.

SEE ALSO         top

       systemd(1), sd-id128(3), machine-id(5), random(4),
       sd_id128_randomize(3)

COLOPHON         top

       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
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       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

systemd 231                                          SD_ID128_GET_MACHINE(3)