sd_bus_message_read_array(3) — Linux manual page

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

SD_BUS_MESSAGE_READ_ARRAY(3)us_message_read_arrayS_MESSAGE_READ_ARRAY(3)

NAME         top

       sd_bus_message_read_array - Access an array of elements in a
       message

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       int sd_bus_message_read_array(sd_bus_message *m, char type,
                                     const void **ptr, size_t *size);

DESCRIPTION         top

       sd_bus_message_read_array() provides access to an array elements
       in the bus message m. The "read pointer" in the message must be
       right before an array of type type. As a special case, type may
       be NUL, in which case any trivial type is acceptable. A pointer
       to the array data is returned in the parameter ptr and the size
       of array data (in bytes) is returned in the parameter size. If
       the returned size parameter is 0, a valid non-null pointer will
       be returned as ptr, but it may not be dereferenced. The data is
       aligned as appropriate for the data type. The data is part of the
       message — it may not be modified and is valid only as long as the
       message is referenced. After this function returns, the "read
       pointer" points at the next element after the array.

       Note that this function only supports arrays of trivial types,
       i.e. arrays of booleans, the various integer types, as well as
       floating point numbers. In particular it may not be used for
       arrays of strings, structures or similar.

RETURN VALUE         top

       On success and when an array was read,
       sd_bus_message_read_array() returns an integer greater than zero.
       If invoked while inside a container element (such as an array,
       e.g. when operating on an array of arrays) and the final element
       of the outer container has been read already and the read pointer
       is thus behind the last element of the outer container this call
       returns 0 (and the returned pointer will be NULL and the size
       will be 0). On failure, it returns a negative errno-style error
       code.

   Errors
       Returned errors may indicate the following problems:

       -EINVAL
           Specified type is invalid or not a trivial type (see above),
           or the message parameter or one of the output parameters are
           NULL.

       -EOPNOTSUPP
           The byte order in the message is different than native byte
           order.

       -EPERM
           The message is not sealed.

       -EBADMSG
           The message cannot be parsed.

SEE ALSO         top

       systemd(1), sd-bus(3), sd_bus_message_read(3),
       sd_bus_message_read_strv(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 2021-08-27.  (At that
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       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 249                                 SD_BUS_MESSAGE_READ_ARRAY(3)

Pages that refer to this page: sd-bus(3)