Copyright (C) 2019 The Qt Company Ltd. SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause This protocol is used internally by Qt for implementing the qt_server_buffer extension on hardware that supports Vulkan external memory . This protocol is not part of the Qt API. It exists purely as an implementation detail and may change from version to version without notice, or even be removed. Informs the client about a newly created server buffer. The "fd" argument is a POSIX file descriptor representing the underlying resources of a Vulkan device memory object as defined in the GL_EXT_memory_object_fd extension.