Converting Matlab function to mex with user defined class object

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I need to create a mex file of a function. One of the arguments of the function is the matlab user defined class object. When I try to convert the function to mex, it gives me an error that the function input does not have valid type and user defined class is not supported by coder.type. Is there any solution to this?

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Accepted Answer

Ryan Livingston
Ryan Livingston on 4 Nov 2014
Edited: Ryan Livingston on 17 Dec 2017
Edit: As of MATLAB R2017a value objects can be inputs and outputs from MEX files.
In earlier releases, MATLAB Coder does not support the input or output arguments of the MEX function being MATLAB objects. One other option you have is to pass the values to the MEX function needed to construct the object and construct the object inside the function being passed to codegen. So rather than:
function y = foo(myObj)
you could use:
function y = foo(arg1,arg2,arg3,)
myObj = MyClass(arg1,arg2,arg3);
Then you can use the object as before in the code and still generate MEX from the function.
Using the struct approach, you could pass in the struct and then re-create the object from the struct inside of the function.

More Answers (1)

Guillaume on 11 Nov 2014
Edited: Guillaume on 11 Nov 2014
To convert a structure back to an object you can do the following function
function object = propfromstruct(object, s)
for fieldname = fieldnames(s)'
o.(fieldname) = s.(fieldname);
catch ex
warning('could not copy field %s due to error %s', fieldname, ex.message);


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