How to make an interface made in C++ Builder responsive during a heavy computation?

c++builder, delphi, user-interface

Solution

`Application.ProcessMessages();` but it has dark side.

Problem

I have a piece of software written in C++ Builder 6 (yes, I know that it's terribly outdated and I'm not going to rewrite it). It does heavy number crunching which takes a few minutes to complete. I want interface to be responsive during these computations. I remember there was an extremely simple solution for this problem in Delphi - calling a special method of form/app, but I can't remember what was it. Any suggestions?

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