Saved from https://nim-lang.org/docs/manual.html#implementation-specific-pragmas-importcpp-pragma

cpp.nim

# Horrible example of how to interface with a C++ engine ... ;-)

{.link: "/usr/lib/libIrrlicht.so".}

{.emit: """
using namespace irr;
using namespace core;
using namespace scene;
using namespace video;
using namespace io;
using namespace gui;
""".}

const
  irr = "<irrlicht/irrlicht.h>"

type
  IrrlichtDeviceObj {.header: irr,
                      importcpp: "IrrlichtDevice".} = object
  IrrlichtDevice = ptr IrrlichtDeviceObj

proc createDevice(): IrrlichtDevice {.
  header: irr, importcpp: "createDevice(@)".}
proc run(device: IrrlichtDevice): bool {.
  header: irr, importcpp: "#.run(@)".}