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

SD_BUS_MESSAGE_GET_MONOTONIC_USEC(3)_get_monotonic_usecGET_MONOTONIC_USEC(3)

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
       clock.

       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.

ERRORS         top

       Returned errors may indicate the following problems:

       -EINVAL
           A specified parameter is invalid.

       -ENODATA
           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
           sd_bus_negotiate_timestamp(3).

NOTES         top

       The sd_bus_message_get_monotonic_usec(),
       sd_bus_message_get_realtime_usec(), and sd_bus_message_get_seqnum()
       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-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 
       ⟨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 2017-09-15.  If you dis‐
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       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

systemd 234                             SD_BUS_MESSAGE_GET_MONOTONIC_USEC(3)

Pages that refer to this page: sd-bus(3)sd_bus_negotiate_fds(3)systemd.directives(7)systemd.index(7)