+9

doc/ipc-design.md

··· 228 [SCM_RIGHTS]: https://man7.org/linux/man-pages/man3/cmsg.3.html 229 [win32handles]: https://lackingrhoticity.blogspot.com/2015/05/passing-fds-handles-between-processes.html 230 [WinSCM_RIGHTS]: https://devblogs.microsoft.com/commandline/af_unix-comes-to-windows/#unsupportedunavailable 0 0 0 0 0 0 0 0 0

··· 228 [SCM_RIGHTS]: https://man7.org/linux/man-pages/man3/cmsg.3.html 229 [win32handles]: https://lackingrhoticity.blogspot.com/2015/05/passing-fds-handles-between-processes.html 230 [WinSCM_RIGHTS]: https://devblogs.microsoft.com/commandline/af_unix-comes-to-windows/#unsupportedunavailable 231 + 232 + ## 32 bits client support on 64 bits server 233 + 234 + On 64 bits system, the server process will typically be a 64 bits executable, 235 + clients may be 32 or 64 bits. As IPC either through socket or shared memory will 236 + share C struct directly, we must pay attention to memory layout. 237 + 238 + All data types must be fixed size and alignments must be based on the 64 bits 239 + targets. On Linux this mostly means `alignas(8)` must be used for (u)int64_t.

+8 -1

src/xrt/include/xrt/xrt_compositor.h

··· 409 * 410 * The layer may be displayed after this point, but must never be 411 * displayed before. 0 0 412 */ 413 alignas(8) int64_t timestamp; 414 ··· 478 */ 479 struct xrt_layer_frame_data 480 { 0 481 alignas(8) int64_t frame_id; 482 int64_t display_time_ns; 483 enum xrt_blend_mode env_blend_mode; ··· 931 struct xrt_session_info 932 { 933 bool is_overlay; 0 934 alignas(8) uint64_t flags; 935 uint32_t z_order; 936 }; ··· 945 //! Number of formats, never changes. 946 uint32_t format_count; 947 948 - //! Supported formats, never changes. 0 0 0 949 alignas(8) int64_t formats[XRT_MAX_SWAPCHAIN_FORMATS]; 950 951 //! Max texture size that GPU supports (size of a single dimension), zero means any size.

··· 409 * 410 * The layer may be displayed after this point, but must never be 411 * displayed before. 412 + * 413 + * alignas for 32 bit client support, 414 */ 415 alignas(8) int64_t timestamp; 416 ··· 480 */ 481 struct xrt_layer_frame_data 482 { 483 + //! alignas for 32 bit client support, see @ref ipc-design 484 alignas(8) int64_t frame_id; 485 int64_t display_time_ns; 486 enum xrt_blend_mode env_blend_mode; ··· 934 struct xrt_session_info 935 { 936 bool is_overlay; 937 + //! alignas for 32 bit client support, see @ref ipc-design 938 alignas(8) uint64_t flags; 939 uint32_t z_order; 940 }; ··· 949 //! Number of formats, never changes. 950 uint32_t format_count; 951 952 + /*! 953 + * Supported formats, never changes. 954 + * alignas for 32 bit client support, see @ref ipc-design 955 + */ 956 alignas(8) int64_t formats[XRT_MAX_SWAPCHAIN_FORMATS]; 957 958 //! Max texture size that GPU supports (size of a single dimension), zero means any size.

+1

src/xrt/include/xrt/xrt_device.h

··· 164 //! Is this input active. 165 bool active; 166 0 167 alignas(8) int64_t timestamp; 168 169 enum xrt_input_name name;

··· 164 //! Is this input active. 165 bool active; 166 167 + //! alignas for 32 bit client support, see @ref ipc-design 168 alignas(8) int64_t timestamp; 169 170 enum xrt_input_name name;

+2

src/xrt/include/xrt/xrt_system.h

··· 169 * All valid values are greater then zero; this is to 170 * make init easier where any cache can start at zero and be guaranteed 171 * to be replaced with a new @ref xrt_system_roles. 0 0 172 */ 173 alignas(8) uint64_t generation_id; 174

··· 169 * All valid values are greater then zero; this is to 170 * make init easier where any cache can start at zero and be guaranteed 171 * to be replaced with a new @ref xrt_system_roles. 172 + * 173 + * alignas for 32 bit client support, see @ref ipc-design 174 */ 175 alignas(8) uint64_t generation_id; 176