DMI_FIELD_GROUP
Description
The macros occupy no bytes, and say something about the fields after them,
see DMI_FIELD.
DMI_FIELD_GROUP-
Beginning of a group of fields the data may end before. The firmware writes the structure of the version of the specification it follows, so a structure is allowed to end at the beginning of any group: the fields of that group and of the ones after it are left unset, and the structure is marked as partial rather than broken. A structure which ends in the middle of a group is decoded up to where it ends, and is marked as incomplete. The fields before the first group are required.
DMI_FIELD_OFFSET-
Boundary the fields after it begin at, counted from the beginning of the structure the way the tables of the specification count it. It says nothing about where the data may end, and is checked while the structure is decoded and encoded, so that a field left out of the declaration, or declared twice, is caught where it happens rather than in the values of everything after it.
Parameters
offset-
Offset of the next field, from the beginning of the structure, header included.
…-
Parameters of a group, given as the designated initializers of
dmi_field_params_t:.since-
Version of the specification the fields of the group appear in, which becomes the level of the structure once the data reaches the group. Groups of the vendors, whose fields no version brings, leave it unset.
.present-
boolmember, seedmi_member, set once every field of the group has been read, and leftfalseif the data ends before the group or in the middle of it. Attributes tell the fields the structure holds from the ones it is too short for by it, and encoding writes the fields of no group the structure does not hold: the canonical mode ends the structure there, and the preserve mode keeps the source bytes of the group as they are.
Errors
A boundary the fields do not reach exactly fails decoding and encoding with
DMI_ERROR_INTERNAL, which tells a declaration that does not match the data.
Example
DMI_FIELD(dmi_cache_t, associativity, dmi_byte_t),
DMI_FIELD_GROUP(.since = DMI_VERSION(3, 1, 0)),
DMI_FIELD_EXTENDED(dmi_cache_t, maximum_size, dmi_dword_t, ...),DMI_FIELD_GROUP(.present = dmi_member(dmi_hpe_trusted_module_t, has_chip)),
DMI_FIELD(dmi_hpe_trusted_module_t, chip, dmi_byte_t),