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For an example of how to use structures in a MATLAB Function block, open the model emldemo_bus_structemldemo_bus_struct.

In this model, a MATLAB Function block receives a bus signal
using the structure `inbus` at input port 1 and outputs
two bus signals from the structures `outbus` at output
port 1 and `outbus1` at output port 2. The input
signal comes from the Bus Creator block `MainBusCreator`,
which bundles signals `ele1`, `ele2`,
and `ele3`. The signal `ele3` is
the output of another Bus Creator block `SubBusCreator`,
which bundles the signals `a1` and `a2`.
The structure `outbus` connects to a Bus Selector block `BusSelector1`;
the structure `outbus1` connects to another Bus
Selector block `BusSelector3`.

To explore the MATLAB^{®} function `fcn`,
double-click the MATLAB Function block. Notice that the code implicitly
defines a local structure variable `mystruct` using
the `struct` function, and uses
this local structure variable to initialize the value of the first
output `outbus`. It initializes the second output `outbus1` to
the value of field `ele3` of structure `inbus`.

Here are the definitions of the structures in the MATLAB Function block in the example, as they appear in the Ports and Data Manager:

Each structure input and output must be defined by a `Simulink.Bus` object
in the base workspace (see Create Structures in MATLAB Function Blocks).
This means that the structure shares the same properties as the bus
object, including number, name, type, and sequence of fields. In this
example, the following bus objects define the structure inputs and
outputs:

The `Simulink.Bus` object `MainBus` defines
structure input `inbus` and structure output `outbus`.
The `Simulink.Bus` object `SubBus` defines
structure output `outbus1`. Based on these definitions, `inbus` and `outbus` have
the same properties as `MainBus` and, therefore,
reference their fields by the same names as the fields in `MainBus`,
using dot notation (see Index Substructures and Fields). Similarly, `outbus1` references
its fields by the same names as the fields in `SubBus`.
Here are the field references for each structure in this example:

Structure | First Field | Second Field | Third Field |
---|---|---|---|

inbus | inbus.ele1 | inbus.ele2 | inbus.ele3 |

outbus | outbus.ele1 | outbus.ele2 | outbus.ele3 |

outbus1 | outbus1.a1 | outbus1.a2 | — |

To learn how to define structures in MATLAB Function blocks, see Create Structures in MATLAB Function Blocks.

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