NixOS2505BuildOpenModelicaFromSource

to all the nerds

Feel free to optimize this build and push it to https://github.com/NixOS/nixpkgs.git or something.

example instructions

Tested for NixOS 25.05 on 2025-06-10.

git clone https://github.com/MBanucu/NixOS2505BuildOpenModelicaFromSource.git
cd NixOS2505BuildOpenModelicaFromSource
nix-shell -p '(import ./default.nix).openmodelica'

Inside the nix shell the most interesting available program is

OMEdit

working features

• compilation of openmodelica-core (using "-DOM_OMEDIT_ENABLE_QTWEBENGINE=ON")
• open OMEdit (using QT_PLUGIN_PATH)
  • SVG icons loading for toolbar (using qt5.full)
  • "Tools" -> "Open Terminal" is starting xterm
    • by linking x-terminal-emulator to xterm in the wrappig process
    • terminal emulator can also be set manually by "Tools -> Options -> General -> Terminal Command"
  • creating Modelica Classes
  • simulation compilation
    • library lgfortran found (using LD_LIBRARY_PATH + gfortran.cc.lib)
    • libraries llapack and lblas found (using LIBRARY_PATH + openblas + lapack)
  • export FMU (using cmake + clang + zip)
  • open mo files created on Windows version of OpenModelica OMEdit (it just works)
  • simulate and plot mo files created on Winsows version of OpenModelica OMEdit (it just works)

disabled / not working

• OM_OMC_ENABLE_FORTRAN + OM_OMC_ENABLE_IPOPT because of fortran linking errors at openmodelica-core
• Ctrl + right click into xterm (using "Tools" -> "Open Terminal" in OMEdit) crashes xterm

unknown workarounds

• Replace -isystem with -I in NIX_CFLAGS_COMPILE and I don't know why this has to be done or how to correct it correctly
• ccache maybe doesn't make sense here since the compilation will only run once on the same codebase and ccache doesn't have access to outside global cache locations