I programmed an enhanced version of this DLL: https://github.com/roseengineering/ExtIO_RTLTCP.
My project shall help you to use high-quality SDR software like HDSDR together with your RTLSDR USB stick also on Linux.
On Linux, install WINE (the Windows software emulator) and the normal Windows version of HDSDR (in WINE). Best is if you build the needed rtl_tcp from https://github.com/librtlsdr/librtlsdr. If that is not possible for you install the Rtl-sdr package from the repository which,...