title: Visual Studio 2019 Preprocessor definition as a result of cmd/sript
body: <p>How can i make a definition as a variable from an evaluated expression? I add in my c++ project ( Visual Studio 2019 ) in the Project-&gt;Configuration Properties-&gt; C/C++ -&gt; Command Line <code>/D &quot;__MYVAL__=$(python3 .\calc.py)&quot;</code> but i get errors <code>&quot;the expression cannot be evaluated&quot;</code>. How can i do this in visual studio 2019 preprocessor on windows?</p>