How can I access nested MATLAB structure fields in my MEX program?

I have created a nested structure in MATLAB:

substruct.a = 1

substruct.b = 2

s.c = 3

s.sub = substruct

Now I would like to write a MEX program that can access certain levels of depth into this structure. I would like to access these fields in my MEX-file.

Answer 1

[MathWorks Support Team]

The following code fragment demonstrates how to extract a substructure and then extract a field from that substructure:

substructure_field_num = mxGetFieldNumber(pa, "substructure");

mxArray *sub = mxGetFieldByNumber(pa, index, substructure_field_num);

field_num = mxGetFieldNumber(sub, "my_field");

mxArray *myField = mxGetFieldByNumber(sub, index, field_num);

For more information on using structures in general, see the documentation for mxGetFieldByNumber and the related PHONEBOOK.C example. You can use the following command in MATLAB to access the documentation:

 doc mxGetFieldByNumber