Create a Simulink data dictionary.

dataDictionary = Simulink.data.dictionary.create('DataDictionary.sldd');

Determine whether the data dictionary contains an Embedded Coder Dictionary. Open the existing Embedded Coder Dictionary or create and open an Embedded Coder Dictionary in the data dictionary.

if coder.dictionary.exist('DataDictionary.sldd')
    
    myCoderDict = coder.dictionary.open('DataDictionary.sldd');
          
else
             
    myCoderDict = coder.dictionary.create('DataDictionary.sldd');
          
end

Because the data dictionary did not contain an Embedded Coder Dictionary, the code creates a coder dictionary in the data dictionary.