NAME

       sd_bus_message_read_array - Access an array of elements in a message

SYNOPSIS

       #include <systemd/sd-bus.h>

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

DESCRIPTION

       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

       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.

HISTORY

       sd_bus_message_read_array() was added in version 240.

SEE ALSO

       systemd(1), sd-bus(3), sd_bus_message_read(3), sd_bus_message_read_strv(3)