* Bump API patch number and header version number to 22 for this update.
Github Issues:
* Translate the subpass self-dependency language into concrete
validity statements, and added a validity statement about the
restrictions on layout parameters (public issue 267).
* Add validity requirement that
slink:VkAttachmentDescription::pname:finalLayout and
slink:VkAttachmentReference::pname:layout must not be
ename:VK_IMAGE_LAYOUT_UNDEFINED or
ename:VK_IMAGE_LAYOUT_PREINITIALIZED (public issue 268).
* Clarify that slink:VkSubpassDescription::pname:pResolveAttachments
layouts are used. Make language consistent with other attachment
arrays (public issue 270).
* Changed 64-bit definition for
dname:VK_DEFINE_NON_DISPATCHABLE_HANDLE to work for x32 platform in
+vk.xml+ and the resulting +vulkan.h+ (public issue 282).
* Add missing error return code for
flink:vkEnumerateInstanceExtensionProperties and
flink:vkEnumerateDeviceExtensionProperties (public issue 285)
* Fix several cases of stext::VkStructName.memberName markup to
stext::VkStructName::pname:memberName, to match other usage in the
spec, and describe this markup in the style guide (public issue
286).
* Modified validity language generation script to avoid redundant
common ancestor language if covered by generic parent language, and
used `Both' instead of `Each' when appropriate (public issue 288).
Internal Issues:
* Add language about behavior of flink:vkAllocateDescriptorSets when
allocation fails due to fragmentation, a new error
ename:VK_ERROR_FRAGMENTED_POOL, and a Note explaining the situation
(internal issue 309).
* For the features of code:PointSize, code:ClipDistance, and
code:CullDistance, the SPIR-V capability is required to be declared
on use (read or write) rather than on decoration (internal issue
359).
* Have desktop versions of GLSL respect precision qualification
(code:mediump and code:lowp) when compiling for Vulkan. These will
get translated to SPIR-V's code:RelaxedPrecision decoration as they
do with OpenGL ES versions of GLSL (ESSL). The default precision of
all types is code:highp when using a desktop version (internal issue
360).
* Add validity statement for slink:VkImageCreateInfo specifying that
multisampled images must be two-dimensional, optimally tiled, and
with a single mipmap level (internal issue 369).
* Add validity statements to slink:VkImageViewCreateInfo disallowing
creation of images or image views with no supported features. Made
some slink:VkImageViewCreateInfo validity statements more precise
and consistent. Added a Note to the <<features,features>> chapter
about formats with no features (internal issue 371).
* Remove +manpages+ from default build targets. Nroff outputs
containing imbedded latexmath will not render properly. Fixing this
is a lot of work for limited use cases (internal issue 401).
Other Commits:
* Fix flink:vkRenderPassBeginInfo::pname:clearValueCount validity
statement to be based on attachment indices rather than the number
of cleared attachments
(Vulkan-LoaderAndValidationLayers/issues/601).
* Convert registry documentation from LaTeX to asciidoc source and
rename from +src/spec/readme.tex+ to +src/spec/registry.txt+.
* Fix lack of Oxford commas in validity language.
* Lots of cleanup of generator scripts and Makefiles to move extension
list for generator into the script arguments instead of the body of
genvk.py, and express better dependencies between XML, scripts, and
generated files.
* Bump API patch number and header version number to 20 for this
update.
Github Issues:
* Replaced existing reference pages by text automatically extracted
from the specification source, or generated from vk.xml in some
cases. This isn't a complete solution for the reference pages, but
puts them in a much better state. The ref pages (only) are now
placed under a CC BY open source license, which is more current than
the obsolete license previously used.
Further improvements to the pages should not edit them directly, but
instead concentrate on the specification source from which the ref
pages are being extracted (public issues 44, 55, 160; internal issue
389).
* Bump API patch number and header version number to 19 for this
update.
Github Issues:
* Clarified how flink:vkGetImageSubresourceLayout interacts with image
layouts (public issue 247).
* Remove ename:VK_IMAGE_LAYOUT_PREINITIALIZED from valid usage rule for
slink:VkImageMemoryBarrier::pname:oldLayout. It is only valid if it is
the current layout (public issue 248).
* Modify valid usage for flink:vkBindBufferMemory so implementations are
free to require a different backing memory size than the buffer size
(public issue 251).
* Clarify that filtering rules for flink:vkCmdBlitImage always apply, and
are usually no-ops if the formats are the same (public issue 253).
* Remove 'non-sparse' from description of
flink:vkGetBufferMemoryRequirements and
flink:vkGetImageMemoryRequirements (public issue 257).
* Remove ename:VK_ERROR_LAYER_NOT_PRESENT error code from
flink:vkCreateDevice (public issue 259).
* Change "must not" to "should not" in constraint on when
flink:vkAcquireNextImageKHR is called in the +VK_KHR_swapchain+ branch
(public issue 262).
* Change type of flink:vkCmdUpdateBuffer::pname:pData from
basetype:uint32_t* to basetype:void* (public issue 263).
* Change should: to must: in description of where additional segments are
placed in the <<[tessellation-tessellator-spacing,Tessellator Spacing>>
section (public issue 264).
Internal Issues:
* Normalize the language of all the compute shader built-ins in the
<<interfaces-builtin-variables,Built-in Variables>> section (internal
issue 323).
* Remove definition of presentation engine internal queue lengths
associated with ename:VK_PRESENT_MODE_FIFO_KHR and
ename:VK_PRESENT_MODE_FIFO_RELAXED_KHR in the <<Window System
Integration,wsi>> chapter (internal issue 374).
* The language of a Note was too broad, and implied that loaders for a
given OS would statically export functions for WSI extensions that
weren't relevant to (or supported on) the OS. Also, removed
"Khronos-provided" since the Android loader isn't (internal issue 380)
Other Commits:
* Add ename:VK_INCOMPLETE to list of return values for
flink:vkGetPipelineCacheData. Spec says this value is returnable, but it
wasn't listed in the error codes.
* Fix "correponds" typo in member definitions for
slink:VkSubpassDescription.
* Bump API patch number and header version number to 12 for this
update.
Github Issues:
* Change valid usage statements intended to be "sub-points" to
be actual sub-points (public issue 66).
* Replace double negation in description of
slink:VkRenderPassBeginInfo::pname:pClearValues (based on public
merge 142).
* Cleanup minor typos in spec, ref pages and XML, including those
proposed in public pull requests 144, 150, 151, 167, 168, 181, and
186.
* Use *strict subset* in describing the partial order of memory
property types for slink:VkMemoryType, and update the style guide
accordingly (public issue 190).
* Fix various "a image" -> "an image" typos (public issue 191).
* Note in the <<fundamentals-validusage,Valid Usage>> and
<<extensions-interactions,Extension Interactions>> sections that
structures defined by extensions which may be passed in structure
chains using the ptext:pNext member must: include initial
ptext:sType and ptext:pNext members (public issue 192).
Internal Issues:
* Remove duplicate language from the description of the pname:fence
parameter to flink:vkQueueSubmit and improve validity language
(internal issue 91).
* Added documentation for "optional" attribute to XML readme.tex/pdf
(internal issue 149).
* Clarify the host-side data validity rules and behavior of
flink:vkFlushMappedMemoryRanges and
flink:vkInvalidateMappedMemoryRanges (internal issue 266).
Other Commits:
* Added clarification to flink:vkCmdFillBuffer regarding the use of
ename:VK_WHOLE_SIZE.
* Fixed and documented implementation of "validextensionstructs"
attribute. in XML processing scripts and readme.tex/pdf.
* Add missing validity statements to flink:vkResetEvent and
flink:vkCmdResetEvent.
* Fix validity for the
ename:VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT flag.
Correct all the draw/dispatch commands to mention optimally tiled
images as well as linear tiled images, and say image VIEWS instead
of images. Add validity statement to flink:vkCmdBlitImage
* Replace the {apiname} macro with hardcoded "Vulkan", now that we've
committed to that name.
* Add the VK_AMD_rasterization_order extension to vk.xml.
* Bump API patch number and header version number to 11 for this
update.
Github Issues:
* Clarify the WSI extension language by switching from the fuzzier
"ownership" language to more-consistent "acquire" language (public
issue 117).
* Clarify that memory barriers apply to all commands in the dependency
chains in the flink:vkGetRenderAreaGranularity command and the
<<synchronization-execution-and-memory-dependencies,Execution And
Memory Dependencies>> section (public issue 132).
* Clarify that a queue family is a set of queues in the
<<fundamentals-execmodel,Execution Model>> section (public issue
166).
* Removed requirement from valid usage language that
VkPresentInfoKHR::waitSemaphoreCount must be greater than 0 (public
issue 171).
* Fix broken internal links, describe structures consistently, use
consistent style for SPIR-V codewords, and tag normative terms that
were missing asciidoc tags (public issue 183 and ancillary
markup/normative language fixes).
* Fix typos for slink:VkPhysicalDeviceLimits member names in
slink:VkImageCreateInfo validity language (public issue 184).
Internal Issues:
* Document that the requested patch version number specified as part
of slink:VkApplicationInfo::pname:apiVersion is ignored when
creating an instance (internal issue 176).
* Clarify handling of extension structs in the
<<fundamentals-validusageValid Usage>> section (internal issue 254).
* Update required slink:VkImageFormatProperties::pname:maxMipLevels to
be limited to the maximum allowed mipmap pyramid size corresponding
to the actual maximum supported size for the format (internal issue
256).
* Modify the <<features-extentperimagetype,Allowed Extent Values Based
On Image Type>> section so the allowed maximum extent is the maximum
image dimension supported for each dimension of the type of texture
being queried (internal issue 257).
* Clarify in the <<spirvenv-module-validation,Validation Rules within
a Module>> section that at least one of the code:LocalSize execution
mode or code:WorkgroupSize decoration is required for each compute
shader entry point in a shader module (internal issue 279).
* Add validity rules for formats in flink:vkCmdClearColorImage and
flink:vkCmdClearDepthStencilImage (internal issue 283).
* Clarify that slink:VkImageFormatProperties::pname:maxResourceSize is
an upper bound, and that it may not be possible to create an image
anywhere near that size (internal issue 284).
Other Commits:
* Fix various minor markup errors reported by validation scripts.
* Change copyright from Khronos Free Use License to Apache 2.0 license
on relevant script/XML/header files. This does not affect the
specification source copyright.
* Bump API patch number and header version number to 10 for this
update.
Github Issues:
* Slightly tweak the <<memory-allocation,Host Memory>> allocator language
so that an application wrapping the standard C alloc/free/realloc
functions is still correct - the previous language was too strong with
regards to freeing memory. Also made certain scenarios clearer - an
implementation may now continue without error if an allocation failed
and it is able to continue correctly (public issue 21).
* Require that etext:VK_*_CREATE_SPARSE_BINDING_BIT is set when the
corresponding etext:VK_*_CREATE_SPARSE_RESIDENCY_BIT is used, in the
<<sparsememory-miptail,Mip Tail Regions>> section and related commands
flink:vkCreateBuffer and flink:vkCreateImage (public issue 84).
* Update the <<features,Features, Limits, and Formats>> chapter to clarify
interactions between optional features and dynamic state for the
pname:depthBiasClamp and pname:wideLines features (public issue 89).
* Describe the code:WorkgroupSize builtin in the
<<interfaces-builtin-variables,Built-In Variables>> section, and update
the <<compute-shaders,Compute Shaders>> section to further clarify how
to set the number of workgroups to execute in a compute shader (public
issue 145).
* Use the term *image subresource* everywhere instead of *subresource*,
except for the special case of *host-accessible subresource*, which may
be either an image subresource or buffer range (public issue 120)
* Add a note to the <<features,Features, Limits, and Formats>> section
about extensibility of structures (Public issue 165).
* Fix return code flink:vkAcquireNextImageKHR when the timeout parameter
is 0 to ename:VK_NOT_READY instead of ename:VK_TIMEOUT (public issue
170).
* Fix typo in slink:VkLayerProperties::pname:apiVersion field (public
issue 172).
Internal Issues:
* Fix a few minor internally-detected typos.
* Minor formatting tweaks to pseudocode in the <<resources,Resource
Creation>> chapter (internal issue 179).
* Fix typo in the definition of point sampling for
elink:VkCullModeFlagBits (internal issue 268).
* Bump API patch number and header version number to 9 for this
update.
Github Issues:
* Fix memory type preorder definition and clarify example list and source
code for slink:VkMemoryRequirements and slink:VkMemoryHeap (public issue
26).
* Ensure slink:VkAllocationCallbacks are properly defined (public issue
73).
* Clarify the WSI extension language by switching from the fuzzier
"ownership" language to more-consistent "acquire" language (public issue
117).
* Add language allowing allocation and freeing of memory scoped to the
duration of any API command in the <<memory-allocation,Memory
Allocation>> section (public issue 136).
* Clarify the explicit location assignment always overrides the inherited
location in the <<interfaces-iointerfaces-locations,Location
Assignment>> section, even for the first member of a block (public issue
141).
* Fixed references to
slink:VkCommandBufferInheritanceInfo::pname:pipelineStatistics (public
issue 158).
* Fix name of slink:VkBufferCopy::pname:size field in validity language
for flink:vkCmdCopyBuffer (public issue 162).
Internal Issues:
* Update GL_KHR_vulkan_glsl specification to clarify disallowance of
spec-const arrays in initializers (internal issue 248).
* Clarify <<interfaces-iointerfaces-matching,Interface Matching>> section
to state that user-defined variable interface must match too (internal
issue 250).
* Bump API patch number and header version number to 8 for this
update.
Github Issues:
* Specify in the validity language for flink:vkBeginCommandBuffer that
pname:commandBuffer mustnot: currently be pending execution (public
issue 96).
* Describe depth comparison using the correct temporary variable names
in the <<textures-depth-compare-operation,Depth Compare Operation>>
section (public issue 100).
* Clarify the order of descriptor update operations in the
flink:vkUpdateDescriptorSets command (public issue 115).
* Specify in the VK_KHR_swapchain extension that
flink:vkAcquireNextImageKHR's pname:semaphore and pname:fence
parameters cannot both be sname:VK_NULL_HANDLE (partly addresses,
but does not fully close, public issue 117 / internal issue 246).
* Change reference to the "lifetime" of a Vulkan command to
"duration", and define the "duration" term (public issue 135).
* Added valid usage language for slink:VkImageLayout to require both
pname:height and pname:depth to be 1 for 1D images and pname:depth
to be 1 for 2D images (public issue 137).
* Fix SPIR-V example code in the
<<descriptorsets-inputattachment,Input Attachment>> section to
properly decorate the code:InputAttachmentIndex (public issue 139).
* Fix reference to nonexistent pname:imageInfo in the description of
flink:VkWriteDescriptorSet to refer to pname:pImageInfo (public
issue 140).
Internal Issues:
* Link to the fixed-function vertex chapter from the drawing chapter
(internal issue #110)
* Fix typo in slink:VkImageCreateInfo validity language:
ptext:maxExtent.sampleCounts -> pname:sampleCounts (internal issue
249).
* Explain why the non-core token etext:VK_IMAGE_LAYOUT_PRESENT_SRC_KHR
is used in the example in the
<<synchronization-semaphores,Semaphores>> section (internal issue
251).
* Attempt to clarify in the VK_KHR_android_surface extension's
<<platformQuerySupport_android,Android Platform Support>> section
that there is no Android-specific WSI query, and why (internal issue
252).
Other Commits:
* Add missing language about ename:VK_INCOMPLETE being returned from
array queries when the passed array is too short, in the
VK_KHR_display, VK_KHR_swapchain, and VK_KHR_surface extensions.
* Bump API patch number and header version number to 6 for this
update.
Github Issues:
* Define 'invocation group' for compute and graphics shaders. Cleanup
definition and use of 'workgroup', and add glossary entries (public
issue 1).
* Various minor editorial fixes (public issue 33).
* Clarify locations for block members in the
<<interfaces-iointerfaces-locations,Location Assignment>>
section (public issue 45).
* Editorial fixes for <<commandbuffer-allocation,Command Buffer
Allocation>> section (public issues 54, 59).
* Clarify behavior of depth test in the <<fragops-depth,Depth
Test>> section (public issues 80, 81).
* Remove discussion of return codes from
flink:vkGetPhysicalDeviceSparseImageFormatProperties and
flink:vkGetImageSparseMemoryRequirements, which don't return values
(public issue 82).
* Allow flink:vkCmdDrawIndirect and flink:vkCmdDrawIndexedIndirect
pname:drawCount of 0, as well as 1, when the multiDrawIndirect
feature is not supported (public issue 88).
* Remove confusing wording in the <<features-limits,Limits>>
section describing the slink:VkPhysicalDeviceLimits
pname:minTexelBufferOffsetAlignment,
pname:minUniformBufferOffsetAlignment, and
pname:minStorageBufferOffsetAlignment members as both minimums and
maximums (public issue 91).
* Clarified that only the RGB components should be affected in places
where sRGB is referred to in the spec, such as ASTC formats. Minor
re-wording to avoid "color space" when actively incorrect, now that
we refer to the Data Format Spec which actually makes a distinction
between color space and transfer function (public issue 94).
* Treat pname:pPropertyCount == 0 consistently in
flink:vkEnumerateInstanceLayerProperties and
flink:vkEnumerateDeviceLayerProperties (public issue 99)
* Cleanup minor editorial issues in chapters 14-17 (public issue 100).
* Clarify definition of flink:vkEnumerateInstanceExtensionProperties
and flink:vkEnumerateDeviceExtensionProperties (public issue 101).
* Define the flink:vkEnumerateInstanceExtensionProperties and
flink:vkEnumerateDeviceExtensionProperties pname:pLayerName
parameter to be a pointer to a null-terminated UTF-8 string (public
issue 101).
* Rearrange "Missing information" references in mandatory format
tables (public issue 101).
* Clarify that the enumerated extensions returned by
flink:vkEnumerateInstanceExtensionProperties and
flink:vkEnumerateDeviceExtensionProperties will only include
extensions provided by the platform or extensions implemented in
implicitly enabled layers (public issue 101).
* Miscellaneous editorial fixes. Include the Vulkan spec patch number
in the PDF title. Fix label on <<fig-non-strict-lines,Non
strict lines>> diagram. Use more easily distinguished symbols in
tables in the <<features-required-format-support,Required
Format Support>> section. Don't require FQDNs used as layer names be
encoded in lower case if not possible, in the
<<extensions-naming-conventions, Extension and Layer Naming
Conventions>> section (public issues 101, 119, 121).
Internal Issues:
* Fixed excessive spacing in tables in XHTML (internal issue 18).
* Clarify that ename:VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT
applies to secondary command buffers. Previously spec only referred
to the members of pname:pCommandBuffers being affected by this bit.
Added a separate slink:VkSubmitInfo Valid Usage restriction
specifying that ename:VK_COMMAND_BUFFER_USAGE_ONE_TIME_SUBMIT_BIT
also applies to any secondary command buffers that are recorded into
the primary command buffers in pname:pCommandBuffers (internal issue
106).
* Clarify that slink:VkDeviceCreateInfo::pname:pEnabledFeatures can be
NULL (internal issue 117).
* Remove "the value of" where it is redundant (e.g. speaking of an API
parameter, struct member, or SPIR-V variable, but not when speaking
of color components) (internal issue 175).
* Forced patch version to always be 0 in the header. Add a
"VK_API_VERSION_<major>_<minor>" macro for people to use to do the
right thing. Add a VK_HEADER_VERSION which captures the header
release number independent of the spec patch number (internal issue
176).
* Correct description of
slink:VkPipelineShaderStageCreateInfo::pname:pName to "a pointer to
a null-terminated UTF-8 string" (internal issue #197).
Other Commits:
* Updated DataFormat spec reference to the new date for revision 5 of
that spec.
* Fixed KEEP option (to retain LaTeX intermediate files) in the
Makefile to be included when edited there, as well as set on the
command line.
* Reserve and add "VK_IMG_filter_cubic" to the registry, and implement
script functionality to add and remove validity from existing
functions. Includes schema and readme changes.
* Update GL_KHR_vulkan_glsl so push_constants do not have descriptor
sets.
* Bump API patch number to 5 for this update.
Github Issues:
* Correctly describe slink:VkPhysicalDeviceProperties pname:deviceName
member as a string, not a pointer to a string. Also one typo fix for
"hetereogeneous" (public issue 4).
* Replace maynot: macro with may: not, and "may: or maynot:" with
"may:" (public issue 4).
* Clarify that redundantly setting the state of a fence or event has
no effect (public issue 4).
* Minor fixes to ref pages to track descriptions of memory bits that
changed in the core spec. Fix name of a member in the description of
sname:sname:VkPipelineMultisampleStateCreateInfo (public issues 8,
13).
* Remove redundant validity statement for
sname:VkGraphicsPipelineCreateInfo::pname:stageCount (public issue
14).
* Fix typos in chapters 7-9 (public issue 14).
* Clarify the example demonstrating the behavior of
code:OpMemoryBarrier in the
<<shaders-execution-memory-ordering,shader memory acces
ordering>> section (public issue 16).
* Specify that freeing mapped memory implicitly unmaps the memory in
the description of flink:vkFreeMemory (public issue 17).
* Forbid allocation callbacks from calling into the API in the
<<memory-allocation,memory allocation>> section (public issue
20).
* Add missing validity rules about size being greater than 0 and
offset being less than size of object. Fix
flink:VkMappedMemoryRange's misinterpretation of offset (public
issues 27, 31).
* Add validity rule disallowing overlapping source/destination
descriptors in flink:VkCopyDescriptorSet (public issue 32).
* Clarify that array and matrix stride has to be a multiple of the
base alignment of the array or matrix in the
<<interfaces-resources-layout,Offset and Stride Assignment>>
section (public issue 38).
* Correct parenthesis floor nesting error in equation for
<<textures-RGB-sexp,RGB to shared exponent conversion>>.
Clarify case of when exp' is forced to 0, avoiding log2(0) undefined
problem (public issue 40).
* Remove redundant statement from the code:FragDepth description in
the <<interfaces-builtin-variables,Built-In Variables>>
section (public issue 47).
* Define the clamping of the
<<textures-level-of-detail-operation,bias added to the scale
factor>> by linking to the slink:VkPhysicalDevice feature
pname:maxSamplerLodBias (public issue 64).
* Fix typo "optimal linear resources" and clarify the set of resources
<<features-limits-bufferImageGranularity,the
pname:bufferImageGranularity resource>> applies to (public issue
67).
* Replace 'descriptor accessed by a pipeline' language for
sname:VkDescriptorSetAllocateInfo with more precise phrasing about
binding a descriptor set before a command that invokes work using
that set (public issue 69).
* tstripadj.svg contained an Inkscape tag which caused Firefox and IE
11 to fail to render it, and was illegal SVG. Generating Plain SVG
from the Inkscape SVG source fixes this (public issue 70).
* Fix validity for sname:VkVertexInputBindingDescription and
sname:VkVertexInputAttributeDescription numbers (public issue 72).
Internal Issues:
* Clarify the meaning of
ename:VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT in
elink:VkFormatFeatureFlagBits with respect to depth compare
(internal issue 107).
* Added a note explaining that ename:VK_QUEUE_TRANSFER_BIT may or may
not be reported for a queue family that already supports
ename:VK_QUEUE_GRAPHICS_BIT or ename:VK_QUEUE_COMPUTE_BIT as the
former is a strict subset of the latter ones (internal issue 116).
* Add validity language for sname:VkDescriptorSetAllocateInfo about
exceeding the descriptor pool capacity (internal issue 140).
* Add ename:VK_INCOMPLETE success code for
flink:vkEnumeratePhysicalDevices query (internal issue 163).
Other Commits:
* Add the VK_NV_glsl_shader extension definitions to the API.
* Update GL_KHR_vulkan_glsl with 1) origin_upper_left as default 2)
specialization array constant semantics.
* Corrected/updated Data Format Specification date.
This is for people to review edits for @philiptaylor's points, but I'll
probably pull equivalent changes back into the private repo and merge
there before bringing it back to github in one of the (hopefully) weekly
updates.
[ChangeLog] This bundles up low-hanging editorial issues from public issue
101. Some items from that issue are more complex and remain to be done.
There's also some related cleanup of the extensions appendix to clarify the
distinction between a Vulkan API command, and the functions and function
pointers corresponding to that command which may be provided by the API
loader and runtime.
Remaining todo from #101 :
- [ ] 24.5.1 "Ab, Yb, Zb" -> "Xb, Yb, Zb".
- [ ] 29.2 "explicitly enabled layers" clarification.
- [ ] 30.3.3 Confusingly similar tiny circle symbols in format tables.
- [ ] 30.3.3 Missing information about some formats.
- [ ] C.3 Clarify or punt on "lower-case UTF-8" in FQDN layer names.
Jon Leech