# Pastebin AQZmk8NV
  type
    HDEVINFO = ptr HANDLE

  const
    DIGCF_PRESENT: uint = 0x00000002
    DIGCF_DEVICEINTERFACE: uint = 0x00000010
    setupDiGetClassDevsInitialFlags: uint = uint(DIGCF_PRESENT or DIGCF_DEVICEINTERFACE)

  var
    GUID_DEVINTERFACE_COMPORT : GUID = GUID(D1: 0x86e0d1e0'i32, D2: 0x8089'i16, D3: 0x11d0, D4: [
      0x9c'i8, 0xe4'i8, 0x08'i8, 0x00'i8, 0x3e'i8, 0x30'i8, 0x1f'i8, 0x73'i8])

  proc SetupDiGetClassDevs(ClassGuid: ptr GUID, Enumerator: cstring, hwndParent: pointer, Flags: DWORD): HDEVINFO
    {.stdcall, importc: "SetupDiGetClassDevsW", dynlib: "setupapi.dll".}

  proc listSerialPorts(): string {.raises:[OSError].} =
    ## Iterate through all of the available serial ports on the system.
    let devInfoSet = SetupDiGetClassDevs(addr GUID_DEVINTERFACE_COMPORT, nil, nil, cast[DWORD](setupDiGetClassDevsInitialFlags))
    if devInfoSet[] == -1:
      raiseOsError(osLastError())