elif sys.platform == 'win32':
                fb_library_name = find_library('fbclient.dll')
                if not fb_library_name:
                    # let's try windows registry
                    if PYTHON_MAJOR_VER == 3:
                        import winreg
                    else:
                        import _winreg as winreg

                    # try find via installed Firebird server
                    baseKey = 'SOFTWARE\Firebird Project\Firebird Server\Instances'
                    key = winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE, baseKey)
                    instFold = winreg.QueryValueEx(key,'DefaultInstance')
                    fb_library_name = os.path.join(os.path.join(instFold[0], 'bin'), 'fbclient.dll')
            else:
                fb_library_name = find_library('fbclient')
                if not fb_library_name:
                    try:
                        x = CDLL('libfbclient.so')
                        fb_library_name = 'libfbclient.so'
                    except:
                        pass

C:\Program Files (x86)\Firebird-2.5.2.26540-0_Win32\bin>instreg.exe i
Firebird has been successfully installed in the registry.

.......................
static const char* const REG_KEY_ROOT_COMPANY	= "SOFTWARE\\Firebird Project";
static const char* const REG_KEY_ROOT_PRODUCT	= "SOFTWARE\\Firebird Project\\Firebird Server";
static const char* const REG_KEY_ROOT_INSTANCES	= "SOFTWARE\\Firebird Project\\Firebird Server\\Instances";
.......................

...................
	if (sw_version)
		printf("instreg version %s\n", FB_VERSION);

	if (sw_command == COMMAND_NONE)
		usage_exit();

	HKEY hkey_node = HKEY_LOCAL_MACHINE;

	USHORT ret;
	switch (sw_command)
	{
		case COMMAND_INSTALL:
			ret = REGISTRY_install(hkey_node, directory, reg_error);
			if (ret != FB_SUCCESS)
				printf ("Firebird has not been installed in the registry.\n");
			else
				printf("Firebird has been successfully installed in the registry.\n");
			break;
................

...................
HKEY hkey_instances;
	DWORD disp;
	SLONG status = RegCreateKeyEx(hkey_rootnode,
			REG_KEY_ROOT_INSTANCES,
			0,
			"",
			REG_OPTION_NON_VOLATILE,
			KEY_WRITE,
			NULL, &hkey_instances, &disp);
	if (status != ERROR_SUCCESS) {
		return (*err_handler) (status, "RegCreateKeyEx", NULL);
	}

	TEXT path_name[MAXPATHLEN];
	TEXT* p;
	USHORT len = GetFullPathName(directory, sizeof(path_name), path_name, &p);
	if (len && path_name[len - 1] != '/' && path_name[len - 1] != '\\')
	{
		path_name[len++] = '\\';
		path_name[len] = 0;
	}

	if ((status = RegSetValueEx(hkey_instances, FB_DEFAULT_INSTANCE, 0,
			REG_SZ, reinterpret_cast<const BYTE*>(path_name),
			(DWORD) (len + 1))) != ERROR_SUCCESS)
	{
		(*err_handler) (status, "RegSetValueEx", hkey_instances);

		// Removes the "Instances" key if we just created it.
		// Else, keep it, because we don't want to trash other instances.
		if (disp == REG_CREATED_NEW_KEY)
		{
			RegDeleteKey(hkey_rootnode, REG_KEY_ROOT_INSTANCES);
			cleanup_key(hkey_rootnode, REG_KEY_ROOT_PRODUCT);
			cleanup_key(hkey_rootnode, REG_KEY_ROOT_COMPANY);
		}

		return FB_FAILURE;
	}

	RegCloseKey(hkey_instances);
....................

......................
static const char* const FB_DEFAULT_INSTANCE	= "DefaultInstance";
......................