sd_bus_message_get_realtime_usec(3) — Linux manual page



NAME         top

       sd_bus_message_get_monotonic_usec, sd_bus_message_get_realtime_usec,
       sd_bus_message_get_seqnum - Retrieve the sender timestamps and
       sequence number of a message

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       int sd_bus_message_get_monotonic_usec(sd_bus_message *message,
                                             uint64_t *usec);

       int sd_bus_message_get_realtime_usec(sd_bus_message *message,
                                            uint64_t *usec);

       int sd_bus_message_get_seqnum(sd_bus_message *message,
                                     uint64_t *seqnum);

DESCRIPTION         top

       sd_bus_message_get_monotonic_usec() returns the monotonic timestamp
       of the time the message was sent. This value is in microseconds since
       the CLOCK_MONOTONIC epoch, see clock_gettime(2) for details.

       Similarly, sd_bus_message_get_realtime_usec() returns the realtime
       (wallclock) timestamp of the time the message was sent. This value is
       in microseconds since Jan 1st, 1970, i.e. in the CLOCK_REALTIME

       sd_bus_message_get_seqnum() returns the kernel-assigned sequence
       number of the message. The kernel assigns a global, monotonically
       increasing sequence number to all messages transmitted on the local
       system, at the time the message was sent. This sequence number is
       useful for determining message send order, even across different
       buses of the local system. The sequence number combined with the boot
       ID of the system (as returned by sd_id128_get_boot(3)) is a suitable
       globally unique identifier for bus messages.

       Note that the sending order and receiving order of messages might
       differ, in particular for broadcast messages. This means that the
       sequence number and the timestamps of messages a client reads are not
       necessarily monotonically increasing.

       These timestamps and the sequence number are attached to each message
       by the kernel and cannot be manipulated by the sender.

       Note that these timestamps are only available on some bus transports,
       and only after support for them has been negotiated with the
       sd_bus_negotiate_timestamp(3) call.

RETURN VALUE         top

       On success, these calls return 0 or a positive integer. On failure,
       these calls return a negative errno-style error code.

       On success, the timestamp or sequence number is returned in the
       specified 64-bit unsigned integer variable.

       Returned errors may indicate the following problems:

           A specified parameter is invalid.

           No timestamp or sequence number information is attached to the
           passed message. This error is returned if the underlying
           transport does not support timestamping or assigning of sequence
           numbers, or if this feature has not been negotiated with

NOTES         top

       These APIs are implemented as a shared library, which can be compiled
       and linked to with the libsystemd pkg-config(1) file.

SEE ALSO         top

       systemd(1), sd-bus(3), sd_bus_new(3), sd_bus_negotiate_timestamp(3),
       clock_gettime(2), sd_id128_get_boot(3)

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug
       report for this manual page, see
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2020-11-01.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-11-01.)  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 im‐
       provements to the information in this COLOPHON (which is not part of
       the original manual page), send a mail to

systemd 247                             SD_BUS_MESSAGE_GET_MONOTONIC_USEC(3)

Pages that refer to this page: sd_bus_get_creds_mask(3)sd_bus_negotiate_creds(3)sd_bus_negotiate_fds(3)sd_bus_negotiate_timestamp(3)30-systemd-environment-d-generator(7)systemd.index(7)