rtaudio | common API for realtime audio input

I have two similar projects on the same machine. Their difference is that one is using GUI (Qt and Qwt) and the other is not. As the result, the one that has Qt is using qmake to compile and the other one cmake.

The project itself is about signal processing and working with audio. I decided to use RtAudio for capturing audio signal. I can compile and run the example code fine when I'm compiling with cmake but when I try to compile the other project using qmake, it fails.

The problem is jack (audio library) which is not found when compiling using qmake. But first, let's start with the project that works. Here's what I have in my CMakeLists.txt file:

An audio library I'm using takes a callback function as an argument, which writes audio into a buffer.

I'm writing a class called Instrument, in which I have a method oscillator() which writes a sine wave to the buffer:

I’m using C++ on visual studio 2019 and having issues trying to link my project to PortAudio. When I use the RtAudio header file in a project, I get the error message "MidiInDummy: This class provides no functionality." Most solutions I can find online say to add __WINDOWS_MM__ to the pre-processor definitions and link to winmm.lib (as instructed on https://www.music.mcgill.ca/~gary/rtmidi/) However, having done this, I am still getting the same problem.

I'm trying to make an audio software (a DAW) using Electron to create the window and c++ to play audio / generate audio / apply audio effects.

I have been searching for a simple, powerful, and cross-platform library to play and process audio, and I've found The Synthesis Toolkit and I'm really happy with it.

Here is the code (it's from the STK demo programs):