Matlab coder error from conversion to C++.

I want to conversion matlab wsolaTSM.m and pitchShiftViaTSM.m to C++ code.

So I success these but little bit problem.

When I converion to C++ in matlab coder error message below.

[error message]

The left-hand side has been constrained to be non-complex, but the right-hand side is complex. To correct this problem, make the right-hand side real using the function REAL, or change the initial assignment to the left-hand side variable to be a complex value using the COMPLEX function.

[matlab code]

%%%%%%%%%%%%%%

stft.m

%%%%%%%%%%%%%%

% spectrogram calculation

%%%%%%%%%%%%%%

spec = zeros(winLenHalf+1,numOfFrames);

for i = 1 : numOfFrames

xi = xPadded(winPos(i):winPos(i) + winLen - 1) .* w;

if parameter.fftShift == 1

xi = fftshift(xi);

end

Xi = fft(xi);

spec(:,i) = Xi(1:winLenHalf+1); %-> error occured code

end

%%%%%%%%%%%%%%

So I modified code like this.

spec(:,i) = real(Xi(1:winLenHalf+1));

but

The sound of the converted wave file is low.

The sound quality is poor.

[Question]

Is there a way to convert it to C++ code without changing the sound quality?

The code is as follows and is a complex code made up of several functions.

https://www.audiolabs-erlangen.de/resources/MIR/TSMtoolbox/

Thank you for reading to my question.