matPutVariable output size limitation

I'm using matputvariable to write out an array of data from a compiled MATLAB executable. This works fine until I try to run my application longer and write out more data, then the application ends but only the 128 byte output file is written. No error message and no data. Is there a max size limitation?

mxArray * outputLevel_1 = mxCreateStructArray(numDim, dims, 2, outputLevel_1_fields);
matPutVariable(outputFile, "simData", outputLevel_1);

https://www.mathworks.com/help/matlab/apiref/matputvariable.html

[James Tursa]

Have you checked to ensure you are not writing beyond valid memory when storing the data? You haven't shown us the code for this. How big does the variable get before you get the problem?