In a local writable folder, create the functions struct_fcn.m

function [out, y] = struct_fcn(in)
    % create a nested struct
    z = struct('prop1', struct('subprop1', 0, 'subprop2', [3 4 45]));
    % copy over the struct
    y = z;
    y.prop1.subprop1 = y.prop1.subprop1 + in;
    out = y.prop1.subprop1;
end

In the same folder, create a test file, struct_fcn_tb.m, that calls the function.

for ii = 1:10
    struct_fcn(ii);
end

From the apps gallery, open the Fixed-Point Converter app.

On the Select Source Files page, browse to the struct_fcn.m file, and click Open.

Click Next. On the Define Input Types page, enter the test file that exercises the struct_fcn function. Browse to select the struct_fcn_tb.m file. Click Autodefine Input Types.

Click Next. The app generates an instrumented MEX function for your entry-point MATLAB function. On the Convert to Fixed-Point page, click Simulate to simulate the function, gather range information, and propose data types.

When the names, number, and types of fields of two or more structures match, the Fixed-Point Converter app proposes a unified type. In this example, the range of z.prop1.subprop1 is [0,0], while the range of y.prop1.subprop1 is [0,10]. The app proposes a data type of numerictype(0,4,0) for both z.prop1.subprop1 and y.prop1.subprop1 based on the union of the ranges of the two fields.

Click Convert.

The Fixed-Point Converter converts the function containing the structures to fixed point and generates the struct_fcn_fixpt.m file.