Imaginary parts of FFT in C++ project are absent

Hello! I need to invoke matlab FFT from c++ project. I'm new to matlab-c++ interaction, and I've faced with the problem that auto generated c++ library function returns only real parts of FFT vector. Here is my matlab function:

function X = fft_test(x)
%#function fft
  X = fft(x);
end

And this is how I invoke it from c++ project:

mwArray xData(size, 1, mxDOUBLE_CLASS, mxREAL);
xData.SetData(x, size);
mwArray resultData;
fft_test(1, resultData, xData);
resultData.GetData(result, size);

(here x is a pointer to the first array element)

After such action I have only real parts in the "result" vector. What I do wrong?