Have a C shared library call a Matlab callback function

Hello, I have a C shared library that I load in my Matlab script. One of the functions of that shared library allows to register a callback function. The shared library will then call-back the registered function if function handleCallback is called. My problem is, I don't know how to pass the Matlab function to my shared library. See function registerCallback in my code below:

Following is the shared library interface object:

    classdef myInterfaceObject

        properties
            libName;
        end

        methods
            %constructor
            function obj = myInterfaceObject(libname)
                obj.libName = libname;
                if ~libisloaded(obj.libName)
                    loadlibrary(obj.libName,@mySharedLibraryProto);
                end
            end

            %destructor
            function delete(obj)
                unloadlibrary(obj.libName);
            end

            %the callback function we want to be called by the c shared library
            function myMatlabCallback(obj,data)
                disp('Inside myMatlabCallback');
            end

            %function to register the callback function above
            function registerCallback(obj)
                fPtr = libpointer('voidPtr',@obj.masterCb);
                calllib(obj.libName,'c_registerCallbackFunction',fPtr);
            end

            %function that will trigger the callback call
            function handleCallback(obj)
                calllib(obj.libName,'c_handleCallback');
            end
        end
    end

Following is my proto file for the shared library:

    function [methodinfo,structs,enuminfo,ThunkLibName]=mySharedLibraryProto

    ival={cell(1,0)};
    structs=[];
    enuminfo=[];
    fcnNum=1;
    fcns=struct('name',ival,'calltype',ival,'LHS',ival,'RHS',ival,'alias',ival);
    ThunkLibName=[];

    fcns.name{fcnNum}='c_registerCallbackFunction'; 
    fcns.calltype{fcnNum}='cdecl'; 
    fcns.LHS{fcnNum}=[]; 
    fcns.RHS{fcnNum}={'voidPtr'};
    fcnNum=fcnNum+1;

    fcns.name{fcnNum}='c_handleCallback'; 
    fcns.calltype{fcnNum}='cdecl'; 
    fcns.LHS{fcnNum}=[]; 
    fcns.RHS{fcnNum}=[];
    fcnNum=fcnNum+1;

    methodinfo=fcns;

And following is my test script:

    function test()
        objectInstance=myInterfaceObject('mySharedLibrary');
        objectInstance.registerCallback();
        objectInstance.handleCallback();
        objectInstance.delete();
    end

Thanks for any help!