| Name |
| |
| NV_stream_socket |
| NV_stream_socket_unix |
| NV_stream_socket_inet |
| |
| Name Strings |
| |
| EGL_NV_stream_socket |
| EGL_NV_stream_socket_unix |
| EGL_NV_stream_socket_inet |
| |
| Contributors |
| |
| Daniel Kartch |
| Bogdan Naodovic |
| James Jones |
| Zander Clucas |
| Tarun Bansal |
| |
| Contacts |
| |
| Daniel Kartch, NVIDIA (dkartch 'at' nvidia.com) |
| |
| Status |
| |
| Draft |
| |
| Version |
| |
| Version 6 - October 27, 2016 |
| |
| Number |
| |
| EGL Extension #115 |
| |
| Extension Type |
| |
| EGL display extension |
| |
| Dependencies |
| |
| EGL_NV_stream_socket requires EGL_NV_stream_remote. |
| |
| EGL_NV_stream_socket_unix requires EGL_NV_stream_socket. |
| |
| EGL_NV_stream_socket_inet requires EGL_NV_stream_socket. |
| |
| Overview |
| |
| These extensions build on the framework for remote streams provided |
| in EGL_NV_stream_remote to define a means for two EGLStream objects |
| representing opposite ends of a single stream to establish |
| communication using a socket. The application is expected to create |
| and connnect both ends of the socket before creating the stream |
| objects. |
| |
| The base EGL_NV_stream_socket extension defines most of the |
| attributes required to initialize the stream objects. The |
| EGL_NV_stream_socket_unix and EGL_NV_stream_socket_inet extensions |
| indicate support for UNIX domain and internet protocol socket types, |
| respectively. Additional extensions may provide support for other |
| socket types. The type of socket is important, as certain operations |
| are only available with certain types, which may influence how the |
| streams are implemented. For instance, UNIX domain sockets allow |
| file descriptors to be passed between processes, while internet |
| protocol sockets do not. This ability may allow more efficient |
| sharing of resources between the socket endpoints. |
| |
| An application using this extension will bear some similarity to the |
| example code from the EGL_KHR_stream_cross_process_fd extension, |
| which also uses sockets to establish the communication between two |
| processes and then create a pair of EGLStream objects. The key |
| difference is that in that case, the sockets are merely a temporary |
| means to an end to pass a file descriptor between the processes. |
| Once that is accomplished, the sockets are discarded. |
| |
| The file descriptor used by that extension may represent an |
| underlying object such as shared memory which allows more efficient |
| communication than the sockets themselves. However, there is nothing |
| preventing an implementation of EGL_NV_stream_socket from creating |
| and passing such a file descriptor as well, gaining the same |
| efficiency. Therefore, a protocol based on sockets will work at |
| least as well as one based on file descriptors, with the added |
| benefit of being more portable. |
| |
| New Types |
| |
| None |
| |
| New Functions |
| |
| None |
| |
| New Tokens for EGL_NV_stream_socket |
| |
| Accepted by eglCreateStreamKHR and returned by eglQueryStreamKHR |
| when attribute is EGL_STREAM_PROTOCOL_NV: |
| |
| EGL_STREAM_PROTOCOL_SOCKET_NV 0x324B |
| |
| Accepted as attribute names by eglCreateStreamKHR and |
| eglQueryStreamKHR functions |
| |
| EGL_SOCKET_HANDLE_NV 0x324C |
| EGL_SOCKET_TYPE_NV 0x324D |
| |
| New Tokens for EGL_NV_stream_socket_unix |
| |
| Accepted by eglCreateStreamKHR and returned by eglQueryStreamKHR |
| when attribute is EGL_SOCKET_TYPE_NV: |
| |
| EGL_SOCKET_TYPE_UNIX_NV 0x324E |
| |
| New Tokens for EGL_NV_stream_socket_inet |
| |
| Accepted by eglCreateStreamKHR and returned by eglQueryStreamKHR |
| when attribute is EGL_SOCKET_TYPE_NV: |
| |
| EGL_SOCKET_TYPE_INET_NV 0x324F |
| |
| Add to list of failures in section "3.10.1 Creating an EGLStream" in EGL_KHR stream: |
| |
| - EGL_BAD_MATCH is generated if the value of EGL_STREAM_PROTOCOL_NV |
| is EGL_STREAM_PROTOCOL_SOCKET_NV and values are not provided for |
| EGL_SOCKET_HANDLE_NV and EGL_SOCKET_TYPE_NV. |
| |
| Add to "Table 3.10.4.4 EGLStream Attributes" in EGL_KHR_stream: |
| |
| Attribute Read/Write Type Section |
| -------------------------- ---------- ------ ---------- |
| EGL_SOCKET_HANDLE_NV io EGLint 3.10.4.y |
| EGL_SOCKET_TYPE_NV io EGLint 3.10.4.y+1 |
| |
| In section "3.10.4.x+1 EGL_STREAM_PROTOCOL_NV Attribute" of |
| EGL_NV_stream_remote, add EGL_STREAM_PROTOCOL_SOCKET_NV to the list of |
| legal values and add |
| |
| A value of EGL_STREAM_PROTOCOL_SOCKET_NV indicates that the stream |
| is a remote stream whose communication is established using a socket |
| connection provided by the application. The details of the messages |
| passed through the socket are implementation dependent, and may be |
| influenced by the stream and socket types. This value for the |
| EGL_STREAM_PROTOCOL_NV attribute is compatible with values of |
| EGL_STREAM_CROSS_OBJECT_NV, EGL_STREAM_CROSS_DISPLAY_NV, |
| EGL_STREAM_CROSS_PROCESS_NV, and EGL_STREAM_CROSS_PARTITION_NV for |
| the EGL_STREAM_TYPE_NV attribute. |
| |
| Add new subsections to the end of section "3.10.4 EGLStream Attributes" |
| in EGL_KHR_stream: |
| |
| 3.10.4.y EGL_SOCKET_HANDLE_NV Attribute |
| |
| The EGL_SOCKET_HANDLE_NV attribute may be set when the stream |
| is created, and provides the handle to a blocking socket which will |
| be used to communicate with the other endpoint of the stream. If the |
| value of EGL_STREAM_PROTOCOL_NV is not EGL_STREAM_PROTOCOL_SOCKET_NV, |
| this attribute is ignored. |
| |
| The type of this value is operating system dependent, and the |
| default value will be an invalid socket handle for the operating |
| system. In particular, for unix-like operating systems, the value is |
| a socket file descriptor as returned by socket() and related |
| functions, and the default value is -1. |
| |
| Prior to creating the EGLStream object, the application may use the |
| socket handle as it wishes. But once the EGLStream object has been |
| successfully created, it assumes full ownership of this socket. If |
| the application subsequently writes to, reads from, or closes the |
| socket, undefined behavior will result. Furthermore, if any data |
| sent over the socket prior to creating the EGLStream object is not |
| consumed before the opposite EGLStream object is created, undefined |
| behavior will result. |
| |
| When the EGLStream object is deleted, the socket handle will be |
| closed by the stream. |
| |
| 3.10.4.y+1 EGL_SOCKET_TYPE_NV Attribute |
| |
| The EGL_SOCKET_TYPE_NV attribute may be set when the stream is |
| created, and indicates the type of the socket provided by the |
| EGL_STREAM_SOCKET_HANDLE_NV attribute. If the value of |
| EGL_STREAM_PROTOCOL_NV is not EGL_STREAM_PROTOCOL_SOCKET_NV this |
| attribute is ignored. |
| |
| The default value is EGL_NONE. |
| |
| If EGL_NV_stream_socket_unix is present, add to section "3.10.4.y+1 |
| EGL_SOCKET_TYPE_NV Attribute" above: |
| |
| A value of EGL_SOCKET_TYPE_UNIX_NV indicates that the socket handle |
| represents a Unix domain socket, created with SOCK_STREAM type. |
| |
| If EGL_NV_stream_socket_inet is present, add to section "3.10.4.y+1 |
| EGL_SOCKET_TYPE_NV Attribute" above: |
| |
| A value of EGL_SOCKET_TYPE_INET_NV indicates that the socket handle |
| represents an internet protocol socket, created with SOCK_STREAM |
| type. |
| |
| Issues |
| |
| None |
| |
| Revision History |
| |
| #6 (October 27, 2016) Daniel Kartch |
| - Indicate that the socket handle provided should represent |
| a blocking socket. |
| |
| #5 (June 7, 2016) Daniel Kartch |
| - Add contact and clean up in preparation for publication. |
| |
| #4 (September 16, 2015) Zander Clucas |
| - Indicated STREAM_SOCKET_PROTOCOL as compatible with socket |
| type CROSS_PROCESS. |
| |
| #3 (December 16, 2014) Daniel Kartch |
| - Refined overview to clarify comparison with |
| EGL_KHR_cross_process_fd. |
| - Indicated SOCK_STREAM as a requirement for the socket types. |
| |
| #2 (December 11, 2014) Daniel Kartch |
| - Rewrote as NV draft for earlier release. |
| - Reserved enum values. |
| |
| #1 (October 10, 2014) Daniel Kartch |
| - Initial EXT draft |
| |
