From c92a247c688f336b1030da088c09d37cc2d34eed Mon Sep 17 00:00:00 2001
From: Dan Gohman <dev@sunfishcode.online>
Date: Tue, 9 Mar 2021 13:53:23 -0800
Subject: [PATCH] Populate the wasi-io proposal with very preliminary content.

This adds very simple I/O streams and I/O arrays witx definitions,
which match read/write and pread/pwrite from wasi-filesystem, as a
starting point.
---
 standard/io/docs.md              | 1366 ++++++++++++++++++++++++++++++
 standard/io/witx/io_arrays.witx  |   49 ++
 standard/io/witx/io_streams.witx |   32 +
 standard/io/witx/typenames.witx  |  708 ++++++++++++++++
 tools/repo_docs.sh               |    5 +
 5 files changed, 2160 insertions(+)
 create mode 100644 standard/io/docs.md
 create mode 100644 standard/io/witx/io_arrays.witx
 create mode 100644 standard/io/witx/io_streams.witx
 create mode 100644 standard/io/witx/typenames.witx

diff --git a/standard/io/docs.md b/standard/io/docs.md
new file mode 100644
index 0000000..0d256d2
--- /dev/null
+++ b/standard/io/docs.md
@@ -0,0 +1,1366 @@
+# Types
+## <a href="#size" name="size"></a> `size`: `usize`
+An array size.
+
+Note: This is similar to `size_t` in POSIX.
+
+Size: 4
+
+Alignment: 4
+
+## <a href="#filesize" name="filesize"></a> `filesize`: `u64`
+Non-negative file size or length of a region within a file.
+
+Size: 8
+
+Alignment: 8
+
+## <a href="#timestamp" name="timestamp"></a> `timestamp`: `u64`
+Timestamp in nanoseconds.
+
+Size: 8
+
+Alignment: 8
+
+## <a href="#clockid" name="clockid"></a> `clockid`: `Variant`
+Identifiers for clocks.
+
+Size: 4
+
+Alignment: 4
+
+### Variant cases
+- <a href="#clockid.realtime" name="clockid.realtime"></a> `realtime`
+The clock measuring real time. Time value zero corresponds with
+1970-01-01T00:00:00Z.
+
+- <a href="#clockid.monotonic" name="clockid.monotonic"></a> `monotonic`
+The store-wide monotonic clock, which is defined as a clock measuring
+real time, whose value cannot be adjusted and which cannot have negative
+clock jumps. The epoch of this clock is undefined. The absolute time
+value of this clock therefore has no meaning.
+
+## <a href="#errno" name="errno"></a> `errno`: `Variant`
+Error codes returned by functions.
+Not all of these error codes are returned by the functions provided by this
+API; some are used in higher-level library layers, and others are provided
+merely for alignment with POSIX.
+
+Size: 2
+
+Alignment: 2
+
+### Variant cases
+- <a href="#errno.success" name="errno.success"></a> `success`
+No error occurred. System call completed successfully.
+
+- <a href="#errno.2big" name="errno.2big"></a> `2big`
+Argument list too long.
+
+- <a href="#errno.access" name="errno.access"></a> `access`
+Permission denied.
+
+- <a href="#errno.addrinuse" name="errno.addrinuse"></a> `addrinuse`
+Address in use.
+
+- <a href="#errno.addrnotavail" name="errno.addrnotavail"></a> `addrnotavail`
+Address not available.
+
+- <a href="#errno.afnosupport" name="errno.afnosupport"></a> `afnosupport`
+Address family not supported.
+
+- <a href="#errno.again" name="errno.again"></a> `again`
+Resource unavailable, or operation would block.
+
+- <a href="#errno.already" name="errno.already"></a> `already`
+Connection already in progress.
+
+- <a href="#errno.badf" name="errno.badf"></a> `badf`
+Bad file descriptor.
+
+- <a href="#errno.badmsg" name="errno.badmsg"></a> `badmsg`
+Bad message.
+
+- <a href="#errno.busy" name="errno.busy"></a> `busy`
+Device or resource busy.
+
+- <a href="#errno.canceled" name="errno.canceled"></a> `canceled`
+Operation canceled.
+
+- <a href="#errno.child" name="errno.child"></a> `child`
+No child processes.
+
+- <a href="#errno.connaborted" name="errno.connaborted"></a> `connaborted`
+Connection aborted.
+
+- <a href="#errno.connrefused" name="errno.connrefused"></a> `connrefused`
+Connection refused.
+
+- <a href="#errno.connreset" name="errno.connreset"></a> `connreset`
+Connection reset.
+
+- <a href="#errno.deadlk" name="errno.deadlk"></a> `deadlk`
+Resource deadlock would occur.
+
+- <a href="#errno.destaddrreq" name="errno.destaddrreq"></a> `destaddrreq`
+Destination address required.
+
+- <a href="#errno.dom" name="errno.dom"></a> `dom`
+Mathematics argument out of domain of function.
+
+- <a href="#errno.dquot" name="errno.dquot"></a> `dquot`
+Reserved.
+
+- <a href="#errno.exist" name="errno.exist"></a> `exist`
+File exists.
+
+- <a href="#errno.fault" name="errno.fault"></a> `fault`
+Bad address.
+
+- <a href="#errno.fbig" name="errno.fbig"></a> `fbig`
+File too large.
+
+- <a href="#errno.hostunreach" name="errno.hostunreach"></a> `hostunreach`
+Host is unreachable.
+
+- <a href="#errno.idrm" name="errno.idrm"></a> `idrm`
+Identifier removed.
+
+- <a href="#errno.ilseq" name="errno.ilseq"></a> `ilseq`
+Illegal byte sequence.
+
+- <a href="#errno.inprogress" name="errno.inprogress"></a> `inprogress`
+Operation in progress.
+
+- <a href="#errno.intr" name="errno.intr"></a> `intr`
+Interrupted function.
+
+- <a href="#errno.inval" name="errno.inval"></a> `inval`
+Invalid argument.
+
+- <a href="#errno.io" name="errno.io"></a> `io`
+I/O error.
+
+- <a href="#errno.isconn" name="errno.isconn"></a> `isconn`
+Socket is connected.
+
+- <a href="#errno.isdir" name="errno.isdir"></a> `isdir`
+Is a directory.
+
+- <a href="#errno.loop" name="errno.loop"></a> `loop`
+Too many levels of symbolic links.
+
+- <a href="#errno.mfile" name="errno.mfile"></a> `mfile`
+File descriptor value too large.
+
+- <a href="#errno.mlink" name="errno.mlink"></a> `mlink`
+Too many links.
+
+- <a href="#errno.msgsize" name="errno.msgsize"></a> `msgsize`
+Message too large.
+
+- <a href="#errno.multihop" name="errno.multihop"></a> `multihop`
+Reserved.
+
+- <a href="#errno.nametoolong" name="errno.nametoolong"></a> `nametoolong`
+Filename too long.
+
+- <a href="#errno.netdown" name="errno.netdown"></a> `netdown`
+Network is down.
+
+- <a href="#errno.netreset" name="errno.netreset"></a> `netreset`
+Connection aborted by network.
+
+- <a href="#errno.netunreach" name="errno.netunreach"></a> `netunreach`
+Network unreachable.
+
+- <a href="#errno.nfile" name="errno.nfile"></a> `nfile`
+Too many files open in system.
+
+- <a href="#errno.nobufs" name="errno.nobufs"></a> `nobufs`
+No buffer space available.
+
+- <a href="#errno.nodev" name="errno.nodev"></a> `nodev`
+No such device.
+
+- <a href="#errno.noent" name="errno.noent"></a> `noent`
+No such file or directory.
+
+- <a href="#errno.noexec" name="errno.noexec"></a> `noexec`
+Executable file format error.
+
+- <a href="#errno.nolck" name="errno.nolck"></a> `nolck`
+No locks available.
+
+- <a href="#errno.nolink" name="errno.nolink"></a> `nolink`
+Reserved.
+
+- <a href="#errno.nomem" name="errno.nomem"></a> `nomem`
+Not enough space.
+
+- <a href="#errno.nomsg" name="errno.nomsg"></a> `nomsg`
+No message of the desired type.
+
+- <a href="#errno.noprotoopt" name="errno.noprotoopt"></a> `noprotoopt`
+Protocol not available.
+
+- <a href="#errno.nospc" name="errno.nospc"></a> `nospc`
+No space left on device.
+
+- <a href="#errno.nosys" name="errno.nosys"></a> `nosys`
+Function not supported.
+
+- <a href="#errno.notconn" name="errno.notconn"></a> `notconn`
+The socket is not connected.
+
+- <a href="#errno.notdir" name="errno.notdir"></a> `notdir`
+Not a directory or a symbolic link to a directory.
+
+- <a href="#errno.notempty" name="errno.notempty"></a> `notempty`
+Directory not empty.
+
+- <a href="#errno.notrecoverable" name="errno.notrecoverable"></a> `notrecoverable`
+State not recoverable.
+
+- <a href="#errno.notsock" name="errno.notsock"></a> `notsock`
+Not a socket.
+
+- <a href="#errno.notsup" name="errno.notsup"></a> `notsup`
+Not supported, or operation not supported on socket.
+
+- <a href="#errno.notty" name="errno.notty"></a> `notty`
+Inappropriate I/O control operation.
+
+- <a href="#errno.nxio" name="errno.nxio"></a> `nxio`
+No such device or address.
+
+- <a href="#errno.overflow" name="errno.overflow"></a> `overflow`
+Value too large to be stored in data type.
+
+- <a href="#errno.ownerdead" name="errno.ownerdead"></a> `ownerdead`
+Previous owner died.
+
+- <a href="#errno.perm" name="errno.perm"></a> `perm`
+Operation not permitted.
+
+- <a href="#errno.pipe" name="errno.pipe"></a> `pipe`
+Broken pipe.
+
+- <a href="#errno.proto" name="errno.proto"></a> `proto`
+Protocol error.
+
+- <a href="#errno.protonosupport" name="errno.protonosupport"></a> `protonosupport`
+Protocol not supported.
+
+- <a href="#errno.prototype" name="errno.prototype"></a> `prototype`
+Protocol wrong type for socket.
+
+- <a href="#errno.range" name="errno.range"></a> `range`
+Result too large.
+
+- <a href="#errno.rofs" name="errno.rofs"></a> `rofs`
+Read-only file system.
+
+- <a href="#errno.spipe" name="errno.spipe"></a> `spipe`
+Invalid seek.
+
+- <a href="#errno.srch" name="errno.srch"></a> `srch`
+No such process.
+
+- <a href="#errno.stale" name="errno.stale"></a> `stale`
+Reserved.
+
+- <a href="#errno.timedout" name="errno.timedout"></a> `timedout`
+Connection timed out.
+
+- <a href="#errno.txtbsy" name="errno.txtbsy"></a> `txtbsy`
+Text file busy.
+
+- <a href="#errno.xdev" name="errno.xdev"></a> `xdev`
+Cross-device link.
+
+- <a href="#errno.notcapable" name="errno.notcapable"></a> `notcapable`
+Extension: Capabilities insufficient.
+
+## <a href="#rights" name="rights"></a> `rights`: `Record`
+File descriptor rights, determining which actions may be performed.
+
+Size: 8
+
+Alignment: 8
+
+### Record members
+- <a href="#rights.fd_datasync" name="rights.fd_datasync"></a> `fd_datasync`: `bool`
+The right to invoke `fd_datasync`.
+If `path_open` is set, includes the right to invoke
+`path_open` with [`fdflags::dsync`](#fdflags.dsync).
+
+Bit: 0
+
+- <a href="#rights.fd_read" name="rights.fd_read"></a> `fd_read`: `bool`
+The right to invoke `fd_read` and `sock_recv`.
+If [`rights::fd_seek`](#rights.fd_seek) is set, includes the right to invoke `fd_pread`.
+
+Bit: 1
+
+- <a href="#rights.fd_seek" name="rights.fd_seek"></a> `fd_seek`: `bool`
+The right to invoke `fd_seek`. This flag implies [`rights::fd_tell`](#rights.fd_tell).
+
+Bit: 2
+
+- <a href="#rights.fd_fdstat_set_flags" name="rights.fd_fdstat_set_flags"></a> `fd_fdstat_set_flags`: `bool`
+The right to invoke `fd_fdstat_set_flags`.
+
+Bit: 3
+
+- <a href="#rights.fd_sync" name="rights.fd_sync"></a> `fd_sync`: `bool`
+The right to invoke `fd_sync`.
+If `path_open` is set, includes the right to invoke
+`path_open` with [`fdflags::rsync`](#fdflags.rsync) and [`fdflags::dsync`](#fdflags.dsync).
+
+Bit: 4
+
+- <a href="#rights.fd_tell" name="rights.fd_tell"></a> `fd_tell`: `bool`
+The right to invoke `fd_seek` in such a way that the file offset
+remains unaltered (i.e., [`whence::cur`](#whence.cur) with offset zero), or to
+invoke `fd_tell`.
+
+Bit: 5
+
+- <a href="#rights.fd_write" name="rights.fd_write"></a> `fd_write`: `bool`
+The right to invoke `fd_write` and `sock_send`.
+If [`rights::fd_seek`](#rights.fd_seek) is set, includes the right to invoke `fd_pwrite`.
+
+Bit: 6
+
+- <a href="#rights.fd_advise" name="rights.fd_advise"></a> `fd_advise`: `bool`
+The right to invoke `fd_advise`.
+
+Bit: 7
+
+- <a href="#rights.fd_allocate" name="rights.fd_allocate"></a> `fd_allocate`: `bool`
+The right to invoke `fd_allocate`.
+
+Bit: 8
+
+- <a href="#rights.path_create_directory" name="rights.path_create_directory"></a> `path_create_directory`: `bool`
+The right to invoke `path_create_directory`.
+
+Bit: 9
+
+- <a href="#rights.path_create_file" name="rights.path_create_file"></a> `path_create_file`: `bool`
+If `path_open` is set, the right to invoke `path_open` with [`oflags::create`](#oflags.create).
+
+Bit: 10
+
+- <a href="#rights.path_link_source" name="rights.path_link_source"></a> `path_link_source`: `bool`
+The right to invoke `path_link` with the file descriptor as the
+source directory.
+
+Bit: 11
+
+- <a href="#rights.path_link_target" name="rights.path_link_target"></a> `path_link_target`: `bool`
+The right to invoke `path_link` with the file descriptor as the
+target directory.
+
+Bit: 12
+
+- <a href="#rights.path_open" name="rights.path_open"></a> `path_open`: `bool`
+The right to invoke `path_open`.
+
+Bit: 13
+
+- <a href="#rights.fd_readdir" name="rights.fd_readdir"></a> `fd_readdir`: `bool`
+The right to invoke `fd_readdir`.
+
+Bit: 14
+
+- <a href="#rights.path_readlink" name="rights.path_readlink"></a> `path_readlink`: `bool`
+The right to invoke `path_readlink`.
+
+Bit: 15
+
+- <a href="#rights.path_rename_source" name="rights.path_rename_source"></a> `path_rename_source`: `bool`
+The right to invoke `path_rename` with the file descriptor as the source directory.
+
+Bit: 16
+
+- <a href="#rights.path_rename_target" name="rights.path_rename_target"></a> `path_rename_target`: `bool`
+The right to invoke `path_rename` with the file descriptor as the target directory.
+
+Bit: 17
+
+- <a href="#rights.path_filestat_get" name="rights.path_filestat_get"></a> `path_filestat_get`: `bool`
+The right to invoke `path_filestat_get`.
+
+Bit: 18
+
+- <a href="#rights.path_filestat_set_size" name="rights.path_filestat_set_size"></a> `path_filestat_set_size`: `bool`
+The right to change a file's size.
+If `path_open` is set, includes the right to invoke `path_open` with [`oflags::trunc`](#oflags.trunc).
+Note: there is no function named `path_filestat_set_size`. This follows POSIX design,
+which only has `ftruncate` and does not provide `ftruncateat`.
+While such function would be desirable from the API design perspective, there are virtually
+no use cases for it since no code written for POSIX systems would use it.
+Moreover, implementing it would require multiple syscalls, leading to inferior performance.
+
+Bit: 19
+
+- <a href="#rights.path_filestat_set_times" name="rights.path_filestat_set_times"></a> `path_filestat_set_times`: `bool`
+The right to invoke `path_filestat_set_times`.
+
+Bit: 20
+
+- <a href="#rights.path_permissions_set" name="rights.path_permissions_set"></a> `path_permissions_set`: `bool`
+The right to invoke `path_permissions_set`.
+
+Bit: 21
+
+- <a href="#rights.fd_filestat_get" name="rights.fd_filestat_get"></a> `fd_filestat_get`: `bool`
+The right to invoke `fd_filestat_get`.
+
+Bit: 22
+
+- <a href="#rights.fd_filestat_set_size" name="rights.fd_filestat_set_size"></a> `fd_filestat_set_size`: `bool`
+The right to invoke `fd_filestat_set_size`.
+
+Bit: 23
+
+- <a href="#rights.fd_filestat_set_times" name="rights.fd_filestat_set_times"></a> `fd_filestat_set_times`: `bool`
+The right to invoke `fd_filestat_set_times`.
+
+Bit: 24
+
+- <a href="#rights.fd_permissions_set" name="rights.fd_permissions_set"></a> `fd_permissions_set`: `bool`
+The right to invoke `fd_permissions_set`.
+
+Bit: 25
+
+- <a href="#rights.path_symlink" name="rights.path_symlink"></a> `path_symlink`: `bool`
+The right to invoke `path_symlink`.
+
+Bit: 26
+
+- <a href="#rights.path_remove_directory" name="rights.path_remove_directory"></a> `path_remove_directory`: `bool`
+The right to invoke `path_remove_directory`.
+
+Bit: 27
+
+- <a href="#rights.path_unlink_file" name="rights.path_unlink_file"></a> `path_unlink_file`: `bool`
+The right to invoke `path_unlink_file`.
+
+Bit: 28
+
+- <a href="#rights.poll_fd_readwrite" name="rights.poll_fd_readwrite"></a> `poll_fd_readwrite`: `bool`
+If [`rights::fd_read`](#rights.fd_read) is set, includes the right to invoke `poll_oneoff` to subscribe to [`eventtype::fd_read`](#eventtype.fd_read).
+If [`rights::fd_write`](#rights.fd_write) is set, includes the right to invoke `poll_oneoff` to subscribe to [`eventtype::fd_write`](#eventtype.fd_write).
+
+Bit: 29
+
+- <a href="#rights.sock_shutdown" name="rights.sock_shutdown"></a> `sock_shutdown`: `bool`
+The right to invoke `sock_shutdown`.
+
+Bit: 30
+
+## <a href="#fd" name="fd"></a> `fd`: `Handle`
+A file descriptor handle.
+
+Size: 4
+
+Alignment: 4
+
+### Supertypes
+## <a href="#iovec" name="iovec"></a> `iovec`: `Record`
+A region of memory for scatter/gather reads.
+
+Size: 8
+
+Alignment: 4
+
+### Record members
+- <a href="#iovec.buf" name="iovec.buf"></a> `buf`: `Pointer<u8>`
+The address of the buffer to be filled.
+
+Offset: 0
+
+- <a href="#iovec.buf_len" name="iovec.buf_len"></a> `buf_len`: [`size`](#size)
+The length of the buffer to be filled.
+
+Offset: 4
+
+## <a href="#ciovec" name="ciovec"></a> `ciovec`: `Record`
+A region of memory for scatter/gather writes.
+
+Size: 8
+
+Alignment: 4
+
+### Record members
+- <a href="#ciovec.buf" name="ciovec.buf"></a> `buf`: `ConstPointer<u8>`
+The address of the buffer to be written.
+
+Offset: 0
+
+- <a href="#ciovec.buf_len" name="ciovec.buf_len"></a> `buf_len`: [`size`](#size)
+The length of the buffer to be written.
+
+Offset: 4
+
+## <a href="#iovec_array" name="iovec_array"></a> `iovec_array`: `List<iovec>`
+
+Size: 8
+
+Alignment: 4
+
+## <a href="#ciovec_array" name="ciovec_array"></a> `ciovec_array`: `List<ciovec>`
+
+Size: 8
+
+Alignment: 4
+
+## <a href="#filedelta" name="filedelta"></a> `filedelta`: `s64`
+Relative offset within a file.
+
+Size: 8
+
+Alignment: 8
+
+## <a href="#whence" name="whence"></a> `whence`: `Variant`
+The position relative to which to set the offset of the file descriptor.
+
+Size: 1
+
+Alignment: 1
+
+### Variant cases
+- <a href="#whence.set" name="whence.set"></a> `set`
+Seek relative to start-of-file.
+
+- <a href="#whence.cur" name="whence.cur"></a> `cur`
+Seek relative to current position.
+
+- <a href="#whence.end" name="whence.end"></a> `end`
+Seek relative to end-of-file.
+
+## <a href="#dircookie" name="dircookie"></a> `dircookie`: `u64`
+A reference to the offset of a directory entry.
+
+Size: 8
+
+Alignment: 8
+
+### Constants
+- <a href="#dircookie.start" name="dircookie.start"></a> `start`
+
+## <a href="#dirnamlen" name="dirnamlen"></a> `dirnamlen`: `u32`
+The type for the [`dirent::d_namlen`](#dirent.d_namlen) field of [`dirent`](#dirent).
+
+Size: 4
+
+Alignment: 4
+
+## <a href="#inode" name="inode"></a> `inode`: `u64`
+File serial number that is unique within its file system.
+
+Size: 8
+
+Alignment: 8
+
+## <a href="#filetype" name="filetype"></a> `filetype`: `Variant`
+The type of a file descriptor or file.
+
+Size: 1
+
+Alignment: 1
+
+### Variant cases
+- <a href="#filetype.unknown" name="filetype.unknown"></a> `unknown`
+The type of the file descriptor or file is unknown or is different from any of the other types specified.
+
+- <a href="#filetype.block_device" name="filetype.block_device"></a> `block_device`
+The file descriptor or file refers to a block device inode.
+
+- <a href="#filetype.character_device" name="filetype.character_device"></a> `character_device`
+The file descriptor or file refers to a character device inode.
+
+- <a href="#filetype.directory" name="filetype.directory"></a> `directory`
+The file descriptor or file refers to a directory inode.
+
+- <a href="#filetype.regular_file" name="filetype.regular_file"></a> `regular_file`
+The file descriptor or file refers to a regular file inode.
+
+- <a href="#filetype.socket_dgram" name="filetype.socket_dgram"></a> `socket_dgram`
+The file descriptor or file refers to a datagram socket.
+
+- <a href="#filetype.socket_stream" name="filetype.socket_stream"></a> `socket_stream`
+The file descriptor or file refers to a byte-stream socket.
+
+- <a href="#filetype.symbolic_link" name="filetype.symbolic_link"></a> `symbolic_link`
+The file refers to a symbolic link inode.
+
+- <a href="#filetype.fifo" name="filetype.fifo"></a> `fifo`
+The file descriptor or file refers to a FIFO.
+
+## <a href="#dirent" name="dirent"></a> `dirent`: `Record`
+A directory entry.
+
+Size: 24
+
+Alignment: 8
+
+### Record members
+- <a href="#dirent.d_next" name="dirent.d_next"></a> `d_next`: [`dircookie`](#dircookie)
+The offset of the next directory entry stored in this directory.
+
+Offset: 0
+
+- <a href="#dirent.d_ino" name="dirent.d_ino"></a> `d_ino`: [`inode`](#inode)
+The serial number of the file referred to by this directory entry.
+
+Offset: 8
+
+- <a href="#dirent.d_type" name="dirent.d_type"></a> `d_type`: [`filetype`](#filetype)
+The type of the file referred to by this directory entry.
+
+Offset: 16
+
+- <a href="#dirent.d_namlen" name="dirent.d_namlen"></a> `d_namlen`: [`dirnamlen`](#dirnamlen)
+The length of the name of the directory entry.
+
+Offset: 20
+
+## <a href="#advice" name="advice"></a> `advice`: `Variant`
+File or memory access pattern advisory information.
+
+Size: 1
+
+Alignment: 1
+
+### Variant cases
+- <a href="#advice.normal" name="advice.normal"></a> `normal`
+The application has no advice to give on its behavior with respect to the specified data.
+
+- <a href="#advice.sequential" name="advice.sequential"></a> `sequential`
+The application expects to access the specified data sequentially from lower offsets to higher offsets.
+
+- <a href="#advice.random" name="advice.random"></a> `random`
+The application expects to access the specified data in a random order.
+
+- <a href="#advice.willneed" name="advice.willneed"></a> `willneed`
+The application expects to access the specified data in the near future.
+
+- <a href="#advice.dontneed" name="advice.dontneed"></a> `dontneed`
+The application expects that it will not access the specified data in the near future.
+
+- <a href="#advice.noreuse" name="advice.noreuse"></a> `noreuse`
+The application expects to access the specified data once and then not reuse it thereafter.
+
+## <a href="#fdflags" name="fdflags"></a> `fdflags`: `Record`
+File descriptor flags.
+
+Size: 2
+
+Alignment: 2
+
+### Record members
+- <a href="#fdflags.append" name="fdflags.append"></a> `append`: `bool`
+Append mode: Data written to the file is always appended to the file's end.
+
+Bit: 0
+
+- <a href="#fdflags.dsync" name="fdflags.dsync"></a> `dsync`: `bool`
+Write according to synchronized I/O data integrity completion. Only the data stored in the file is synchronized.
+
+Bit: 1
+
+- <a href="#fdflags.nonblock" name="fdflags.nonblock"></a> `nonblock`: `bool`
+Non-blocking mode.
+
+Bit: 2
+
+- <a href="#fdflags.rsync" name="fdflags.rsync"></a> `rsync`: `bool`
+Synchronized read I/O operations.
+
+Bit: 3
+
+- <a href="#fdflags.sync" name="fdflags.sync"></a> `sync`: `bool`
+Write according to synchronized I/O file integrity completion. In
+addition to synchronizing the data stored in the file, the implementation
+may also synchronously update the file's metadata.
+
+Bit: 4
+
+## <a href="#fdstat" name="fdstat"></a> `fdstat`: `Record`
+File descriptor attributes.
+
+Size: 24
+
+Alignment: 8
+
+### Record members
+- <a href="#fdstat.fs_filetype" name="fdstat.fs_filetype"></a> `fs_filetype`: [`filetype`](#filetype)
+File type.
+
+Offset: 0
+
+- <a href="#fdstat.fs_flags" name="fdstat.fs_flags"></a> `fs_flags`: [`fdflags`](#fdflags)
+File descriptor flags.
+
+Offset: 2
+
+- <a href="#fdstat.fs_rights_base" name="fdstat.fs_rights_base"></a> `fs_rights_base`: [`rights`](#rights)
+Rights that apply to this file descriptor.
+
+Offset: 8
+
+- <a href="#fdstat.fs_rights_inheriting" name="fdstat.fs_rights_inheriting"></a> `fs_rights_inheriting`: [`rights`](#rights)
+Maximum set of rights that may be installed on new file descriptors that
+are created through this file descriptor, e.g., through `path_open`.
+
+Offset: 16
+
+## <a href="#device" name="device"></a> `device`: `u64`
+Identifier for a device containing a file system. Can be used in combination
+with [`inode`](#inode) to uniquely identify a file or directory in the filesystem.
+
+Size: 8
+
+Alignment: 8
+
+## <a href="#fstflags" name="fstflags"></a> `fstflags`: `Record`
+Which file time attributes to adjust.
+
+Size: 2
+
+Alignment: 2
+
+### Record members
+- <a href="#fstflags.atim" name="fstflags.atim"></a> `atim`: `bool`
+Adjust the last data access timestamp to the value stored in [`filestat::atim`](#filestat.atim).
+
+Bit: 0
+
+- <a href="#fstflags.atim_now" name="fstflags.atim_now"></a> `atim_now`: `bool`
+Adjust the last data access timestamp to the time of clock [`clockid::realtime`](#clockid.realtime).
+
+Bit: 1
+
+- <a href="#fstflags.mtim" name="fstflags.mtim"></a> `mtim`: `bool`
+Adjust the last data modification timestamp to the value stored in [`filestat::mtim`](#filestat.mtim).
+
+Bit: 2
+
+- <a href="#fstflags.mtim_now" name="fstflags.mtim_now"></a> `mtim_now`: `bool`
+Adjust the last data modification timestamp to the time of clock [`clockid::realtime`](#clockid.realtime).
+
+Bit: 3
+
+## <a href="#lookupflags" name="lookupflags"></a> `lookupflags`: `Record`
+Flags determining the method of how paths are resolved.
+
+Size: 4
+
+Alignment: 4
+
+### Record members
+- <a href="#lookupflags.symlink_follow" name="lookupflags.symlink_follow"></a> `symlink_follow`: `bool`
+As long as the resolved path corresponds to a symbolic link, it is expanded.
+
+Bit: 0
+
+## <a href="#oflags" name="oflags"></a> `oflags`: `Record`
+Open flags used by `path_open`.
+
+Size: 2
+
+Alignment: 2
+
+### Record members
+- <a href="#oflags.create" name="oflags.create"></a> `create`: `bool`
+Create file if it does not exist.
+
+Bit: 0
+
+- <a href="#oflags.directory" name="oflags.directory"></a> `directory`: `bool`
+Fail if not a directory.
+
+Bit: 1
+
+- <a href="#oflags.excl" name="oflags.excl"></a> `excl`: `bool`
+Fail if file already exists.
+
+Bit: 2
+
+- <a href="#oflags.trunc" name="oflags.trunc"></a> `trunc`: `bool`
+Truncate file to size 0.
+
+Bit: 3
+
+## <a href="#linkcount" name="linkcount"></a> `linkcount`: `u64`
+Number of hard links to an inode.
+
+Size: 8
+
+Alignment: 8
+
+## <a href="#permissions" name="permissions"></a> `permissions`: `Record`
+File permissions. This represents the permissions associated with a
+file in a filesystem, and don't fully reflect all the conditions
+which determine whether a given WASI program can access the file.
+
+Size: 1
+
+Alignment: 1
+
+### Record members
+- <a href="#permissions.read" name="permissions.read"></a> `read`: `bool`
+For files, permission to read the file.
+For directories, permission to do `readdir` and access files
+within the directory.
+
+Note: This is similar to the read bit being set on files, and the
+read *and* execute bits being set on directories, in POSIX.
+
+Bit: 0
+
+- <a href="#permissions.write" name="permissions.write"></a> `write`: `bool`
+For files, permission to mutate the file.
+For directories, permission to create, remove, and rename items
+within the directory.
+
+Bit: 1
+
+- <a href="#permissions.execute" name="permissions.execute"></a> `execute`: `bool`
+For files, permission to "execute" the file, using whatever
+concept of "executing" the host filesystem has.
+This flag is not valid for directories.
+
+Bit: 2
+
+- <a href="#permissions.private" name="permissions.private"></a> `private`: `bool`
+For filesystems which have a concept of multiple "users", this flag
+indicates that the file is only accessible by the effective "user"
+that the WASI store uses to access the filesystem, and inaccessible
+to other "users".
+
+Bit: 3
+
+## <a href="#filestat" name="filestat"></a> `filestat`: `Record`
+File attributes.
+
+Size: 64
+
+Alignment: 8
+
+### Record members
+- <a href="#filestat.dev" name="filestat.dev"></a> `dev`: [`device`](#device)
+Device ID of device containing the file.
+
+Offset: 0
+
+- <a href="#filestat.ino" name="filestat.ino"></a> `ino`: [`inode`](#inode)
+File serial number.
+
+Offset: 8
+
+- <a href="#filestat.filetype" name="filestat.filetype"></a> `filetype`: [`filetype`](#filetype)
+File type.
+
+Offset: 16
+
+- <a href="#filestat.permissions" name="filestat.permissions"></a> `permissions`: [`permissions`](#permissions)
+File permissions.
+
+Offset: 17
+
+- <a href="#filestat.nlink" name="filestat.nlink"></a> `nlink`: [`linkcount`](#linkcount)
+Number of hard links to the file.
+
+Offset: 24
+
+- <a href="#filestat.size" name="filestat.size"></a> `size`: [`filesize`](#filesize)
+For regular files, the file size in bytes. For symbolic links, the length in bytes of the pathname contained in the symbolic link.
+
+Offset: 32
+
+- <a href="#filestat.atim" name="filestat.atim"></a> `atim`: [`timestamp`](#timestamp)
+Last data access timestamp.
+
+Offset: 40
+
+- <a href="#filestat.mtim" name="filestat.mtim"></a> `mtim`: [`timestamp`](#timestamp)
+Last data modification timestamp.
+
+Offset: 48
+
+- <a href="#filestat.ctim" name="filestat.ctim"></a> `ctim`: [`timestamp`](#timestamp)
+Last file status change timestamp.
+
+Offset: 56
+
+## <a href="#userdata" name="userdata"></a> `userdata`: `u64`
+User-provided value that may be attached to objects that is retained when
+extracted from the implementation.
+
+Size: 8
+
+Alignment: 8
+
+## <a href="#eventtype" name="eventtype"></a> `eventtype`: `Variant`
+Type of a subscription to an event or its occurrence.
+
+Size: 1
+
+Alignment: 1
+
+### Variant cases
+- <a href="#eventtype.clock" name="eventtype.clock"></a> `clock`
+The time value of clock [`subscription_clock::id`](#subscription_clock.id) has
+reached timestamp [`subscription_clock::timeout`](#subscription_clock.timeout).
+
+- <a href="#eventtype.fd_read" name="eventtype.fd_read"></a> `fd_read`
+File descriptor [`subscription_fd_readwrite::fd`](#subscription_fd_readwrite.fd) has data
+available for reading. This event always triggers for regular files.
+
+- <a href="#eventtype.fd_write" name="eventtype.fd_write"></a> `fd_write`
+File descriptor [`subscription_fd_readwrite::fd`](#subscription_fd_readwrite.fd) has capacity
+available for writing. This event always triggers for regular files.
+
+## <a href="#eventrwflags" name="eventrwflags"></a> `eventrwflags`: `Record`
+The state of the file descriptor subscribed to with
+[`eventtype::fd_read`](#eventtype.fd_read) or [`eventtype::fd_write`](#eventtype.fd_write).
+
+Size: 2
+
+Alignment: 2
+
+### Record members
+- <a href="#eventrwflags.fd_readwrite_hangup" name="eventrwflags.fd_readwrite_hangup"></a> `fd_readwrite_hangup`: `bool`
+The peer of this socket has closed or disconnected.
+
+Bit: 0
+
+## <a href="#event_fd_readwrite" name="event_fd_readwrite"></a> `event_fd_readwrite`: `Record`
+The contents of an [`event`](#event) when type is [`eventtype::fd_read`](#eventtype.fd_read) or
+[`eventtype::fd_write`](#eventtype.fd_write).
+
+Size: 16
+
+Alignment: 8
+
+### Record members
+- <a href="#event_fd_readwrite.nbytes" name="event_fd_readwrite.nbytes"></a> `nbytes`: [`filesize`](#filesize)
+The number of bytes available for reading or writing.
+
+Offset: 0
+
+- <a href="#event_fd_readwrite.flags" name="event_fd_readwrite.flags"></a> `flags`: [`eventrwflags`](#eventrwflags)
+The state of the file descriptor.
+
+Offset: 8
+
+## <a href="#event_u" name="event_u"></a> `event_u`: `Variant`
+The contents of an [`event`](#event).
+
+Size: 24
+
+Alignment: 8
+
+### Variant Layout
+- size: 24
+- align: 8
+- tag_size: 1
+### Variant cases
+- <a href="#event_u.clock" name="event_u.clock"></a> `clock`
+
+- <a href="#event_u.fd_read" name="event_u.fd_read"></a> `fd_read`: [`event_fd_readwrite`](#event_fd_readwrite)
+
+- <a href="#event_u.fd_write" name="event_u.fd_write"></a> `fd_write`: [`event_fd_readwrite`](#event_fd_readwrite)
+
+## <a href="#event" name="event"></a> `event`: `Record`
+An event that occurred.
+
+Size: 40
+
+Alignment: 8
+
+### Record members
+- <a href="#event.userdata" name="event.userdata"></a> `userdata`: [`userdata`](#userdata)
+User-provided value that got attached to [`subscription::userdata`](#subscription.userdata).
+
+Offset: 0
+
+- <a href="#event.error" name="event.error"></a> `error`: [`errno`](#errno)
+If non-zero, an error that occurred while processing the subscription request.
+
+Offset: 8
+
+- <a href="#event.u" name="event.u"></a> `u`: [`event_u`](#event_u)
+The type of the event that occurred, and the contents of the event
+
+Offset: 16
+
+## <a href="#subclockflags" name="subclockflags"></a> `subclockflags`: `Record`
+Flags determining how to interpret the timestamp provided in
+[`subscription_clock::timeout`](#subscription_clock.timeout).
+
+Size: 2
+
+Alignment: 2
+
+### Record members
+- <a href="#subclockflags.subscription_clock_abstime" name="subclockflags.subscription_clock_abstime"></a> `subscription_clock_abstime`: `bool`
+If set, treat the timestamp provided in
+[`subscription_clock::timeout`](#subscription_clock.timeout) as an absolute timestamp of clock
+[`subscription_clock::id`](#subscription_clock.id). If clear, treat the timestamp
+provided in [`subscription_clock::timeout`](#subscription_clock.timeout) relative to the
+current time value of clock [`subscription_clock::id`](#subscription_clock.id).
+
+Bit: 0
+
+## <a href="#subscription_clock" name="subscription_clock"></a> `subscription_clock`: `Record`
+The contents of a [`subscription`](#subscription) when type is [`eventtype::clock`](#eventtype.clock).
+
+Size: 32
+
+Alignment: 8
+
+### Record members
+- <a href="#subscription_clock.id" name="subscription_clock.id"></a> `id`: [`clockid`](#clockid)
+The clock against which to compare the timestamp.
+
+Offset: 0
+
+- <a href="#subscription_clock.timeout" name="subscription_clock.timeout"></a> `timeout`: [`timestamp`](#timestamp)
+The absolute or relative timestamp.
+
+Offset: 8
+
+- <a href="#subscription_clock.precision" name="subscription_clock.precision"></a> `precision`: [`timestamp`](#timestamp)
+The amount of time that the implementation may wait additionally
+to coalesce with other events.
+
+Offset: 16
+
+- <a href="#subscription_clock.flags" name="subscription_clock.flags"></a> `flags`: [`subclockflags`](#subclockflags)
+Flags specifying whether the timeout is absolute or relative
+
+Offset: 24
+
+## <a href="#subscription_fd_readwrite" name="subscription_fd_readwrite"></a> `subscription_fd_readwrite`: `Record`
+The contents of a [`subscription`](#subscription) when type is type is
+[`eventtype::fd_read`](#eventtype.fd_read) or [`eventtype::fd_write`](#eventtype.fd_write).
+
+Size: 4
+
+Alignment: 4
+
+### Record members
+- <a href="#subscription_fd_readwrite.fd" name="subscription_fd_readwrite.fd"></a> `fd`: [`fd`](#fd)
+The file descriptor on which to wait for it to become ready for reading or writing.
+
+Offset: 0
+
+## <a href="#subscription_u" name="subscription_u"></a> `subscription_u`: `Variant`
+The contents of a [`subscription`](#subscription).
+
+Size: 40
+
+Alignment: 8
+
+### Variant Layout
+- size: 40
+- align: 8
+- tag_size: 1
+### Variant cases
+- <a href="#subscription_u.clock" name="subscription_u.clock"></a> `clock`: [`subscription_clock`](#subscription_clock)
+
+- <a href="#subscription_u.fd_read" name="subscription_u.fd_read"></a> `fd_read`: [`subscription_fd_readwrite`](#subscription_fd_readwrite)
+
+- <a href="#subscription_u.fd_write" name="subscription_u.fd_write"></a> `fd_write`: [`subscription_fd_readwrite`](#subscription_fd_readwrite)
+
+## <a href="#subscription" name="subscription"></a> `subscription`: `Record`
+Subscription to an event.
+
+Size: 48
+
+Alignment: 8
+
+### Record members
+- <a href="#subscription.userdata" name="subscription.userdata"></a> `userdata`: [`userdata`](#userdata)
+User-provided value that is attached to the subscription in the
+implementation and returned through [`event::userdata`](#event.userdata).
+
+Offset: 0
+
+- <a href="#subscription.u" name="subscription.u"></a> `u`: [`subscription_u`](#subscription_u)
+The type of the event to which to subscribe, and the contents of the subscription.
+
+Offset: 8
+
+## <a href="#exitcode" name="exitcode"></a> `exitcode`: `u8`
+Exit code generated by a program when exiting.
+
+Size: 1
+
+Alignment: 1
+
+### Constants
+- <a href="#exitcode.success" name="exitcode.success"></a> `success`
+
+- <a href="#exitcode.failure" name="exitcode.failure"></a> `failure`
+
+## <a href="#riflags" name="riflags"></a> `riflags`: `Record`
+Flags provided to `sock_recv`.
+
+Size: 2
+
+Alignment: 2
+
+### Record members
+- <a href="#riflags.recv_peek" name="riflags.recv_peek"></a> `recv_peek`: `bool`
+Returns the message without removing it from the socket's receive queue.
+
+Bit: 0
+
+- <a href="#riflags.recv_waitall" name="riflags.recv_waitall"></a> `recv_waitall`: `bool`
+On byte-stream sockets, block until the full amount of data can be returned.
+
+Bit: 1
+
+## <a href="#roflags" name="roflags"></a> `roflags`: `Record`
+Flags returned by `sock_recv`.
+
+Size: 2
+
+Alignment: 2
+
+### Record members
+- <a href="#roflags.recv_data_truncated" name="roflags.recv_data_truncated"></a> `recv_data_truncated`: `bool`
+Returned by `sock_recv`: Message data has been truncated.
+
+Bit: 0
+
+## <a href="#siflags" name="siflags"></a> `siflags`: `u16`
+Flags provided to `sock_send`. As there are currently no flags
+defined, it must be set to zero.
+
+Size: 2
+
+Alignment: 2
+
+## <a href="#sdflags" name="sdflags"></a> `sdflags`: `Record`
+Which channels on a socket to shut down.
+
+Size: 1
+
+Alignment: 1
+
+### Record members
+- <a href="#sdflags.rd" name="sdflags.rd"></a> `rd`: `bool`
+Disables further receive operations.
+
+Bit: 0
+
+- <a href="#sdflags.wr" name="sdflags.wr"></a> `wr`: `bool`
+Disables further send operations.
+
+Bit: 1
+
+## <a href="#preopentype" name="preopentype"></a> `preopentype`: `Variant`
+Identifiers for preopened capabilities.
+
+Size: 1
+
+Alignment: 1
+
+### Variant cases
+- <a href="#preopentype.dir" name="preopentype.dir"></a> `dir`
+A pre-opened directory.
+
+## <a href="#prestat_dir" name="prestat_dir"></a> `prestat_dir`: `Record`
+The contents of a [`prestat`](#prestat) when its type is [`preopentype::dir`](#preopentype.dir).
+
+Size: 4
+
+Alignment: 4
+
+### Record members
+- <a href="#prestat_dir.pr_name_len" name="prestat_dir.pr_name_len"></a> `pr_name_len`: [`size`](#size)
+The length of the directory name for use with `fd_prestat_dir_name`.
+
+Offset: 0
+
+## <a href="#prestat" name="prestat"></a> `prestat`: `Variant`
+Information about a pre-opened capability.
+
+Size: 8
+
+Alignment: 4
+
+### Variant Layout
+- size: 8
+- align: 4
+- tag_size: 1
+### Variant cases
+- <a href="#prestat.dir" name="prestat.dir"></a> `dir`: [`prestat_dir`](#prestat_dir)
+When type is [`preopentype::dir`](#preopentype.dir):
+
+# Modules
+## <a href="#wasi_ephemeral_io_arrays" name="wasi_ephemeral_io_arrays"></a> wasi_ephemeral_io_arrays
+### Imports
+#### Memory
+### Functions
+
+---
+
+#### <a href="#advise" name="advise"></a> `advise(fd: fd, offset: filesize, len: filesize, advice: advice) -> Result<(), errno>`
+Provide file advisory information on a file descriptor.
+Note: This is similar to `posix_fadvise` in POSIX.
+
+##### Params
+- <a href="#advise.fd" name="advise.fd"></a> `fd`: [`fd`](#fd)
+
+- <a href="#advise.offset" name="advise.offset"></a> `offset`: [`filesize`](#filesize)
+The offset within the file to which the advisory applies.
+
+- <a href="#advise.len" name="advise.len"></a> `len`: [`filesize`](#filesize)
+The length of the region to which the advisory applies.
+
+- <a href="#advise.advice" name="advise.advice"></a> `advice`: [`advice`](#advice)
+The advice.
+
+##### Results
+- <a href="#advise.error" name="advise.error"></a> `error`: `Result<(), errno>`
+
+###### Variant Layout
+- size: 8
+- align: 4
+- tag_size: 4
+###### Variant cases
+- <a href="#advise.error.ok" name="advise.error.ok"></a> `ok`
+
+- <a href="#advise.error.err" name="advise.error.err"></a> `err`: [`errno`](#errno)
+
+
+---
+
+#### <a href="#pread" name="pread"></a> `pread(fd: fd, iovs: iovec_array, offset: filesize) -> Result<size, errno>`
+Read from a file descriptor, without using and updating the file descriptor's offset.
+Note: This is similar to `preadv` in Linux (and other Unix-es).
+
+##### Params
+- <a href="#pread.fd" name="pread.fd"></a> `fd`: [`fd`](#fd)
+
+- <a href="#pread.iovs" name="pread.iovs"></a> `iovs`: [`iovec_array`](#iovec_array)
+List of scatter/gather vectors in which to store data.
+
+- <a href="#pread.offset" name="pread.offset"></a> `offset`: [`filesize`](#filesize)
+The offset within the file at which to read.
+
+##### Results
+- <a href="#pread.error" name="pread.error"></a> `error`: `Result<size, errno>`
+The number of bytes read.
+
+###### Variant Layout
+- size: 8
+- align: 4
+- tag_size: 4
+###### Variant cases
+- <a href="#pread.error.ok" name="pread.error.ok"></a> `ok`: [`size`](#size)
+
+- <a href="#pread.error.err" name="pread.error.err"></a> `err`: [`errno`](#errno)
+
+
+---
+
+#### <a href="#pwrite" name="pwrite"></a> `pwrite(fd: fd, iovs: ciovec_array, offset: filesize) -> Result<size, errno>`
+Write to a file descriptor, without using and updating the file descriptor's offset.
+Note: This is similar to `pwritev` in Linux (and other Unix-es).
+
+Like Linux (and other Unix-es), any calls of [`pwrite`](#pwrite) (and other
+functions to read or write) for a regular file by other threads in the
+WASI process should not be interleaved while [`pwrite`](#pwrite) is executed.
+
+##### Params
+- <a href="#pwrite.fd" name="pwrite.fd"></a> `fd`: [`fd`](#fd)
+
+- <a href="#pwrite.iovs" name="pwrite.iovs"></a> `iovs`: [`ciovec_array`](#ciovec_array)
+List of scatter/gather vectors from which to retrieve data.
+
+- <a href="#pwrite.offset" name="pwrite.offset"></a> `offset`: [`filesize`](#filesize)
+The offset within the file at which to write.
+
+##### Results
+- <a href="#pwrite.error" name="pwrite.error"></a> `error`: `Result<size, errno>`
+The number of bytes written.
+
+###### Variant Layout
+- size: 8
+- align: 4
+- tag_size: 4
+###### Variant cases
+- <a href="#pwrite.error.ok" name="pwrite.error.ok"></a> `ok`: [`size`](#size)
+
+- <a href="#pwrite.error.err" name="pwrite.error.err"></a> `err`: [`errno`](#errno)
+
+## <a href="#wasi_ephemeral_io_streams" name="wasi_ephemeral_io_streams"></a> wasi_ephemeral_io_streams
+### Imports
+#### Memory
+### Functions
+
+---
+
+#### <a href="#read" name="read"></a> `read(fd: fd, iovs: iovec_array) -> Result<size, errno>`
+Read from a file descriptor.
+Note: This is similar to `readv` in POSIX.
+
+##### Params
+- <a href="#read.fd" name="read.fd"></a> `fd`: [`fd`](#fd)
+
+- <a href="#read.iovs" name="read.iovs"></a> `iovs`: [`iovec_array`](#iovec_array)
+List of scatter/gather vectors to which to store data.
+
+##### Results
+- <a href="#read.error" name="read.error"></a> `error`: `Result<size, errno>`
+The number of bytes read.
+
+###### Variant Layout
+- size: 8
+- align: 4
+- tag_size: 4
+###### Variant cases
+- <a href="#read.error.ok" name="read.error.ok"></a> `ok`: [`size`](#size)
+
+- <a href="#read.error.err" name="read.error.err"></a> `err`: [`errno`](#errno)
+
+
+---
+
+#### <a href="#write" name="write"></a> `write(fd: fd, iovs: ciovec_array) -> Result<size, errno>`
+Write to a file descriptor.
+Note: This is similar to `writev` in POSIX.
+
+Like POSIX, any calls of [`write`](#write) (and other functions to read or write)
+for a regular file by other threads in the WASI process should not be
+interleaved while [`write`](#write) is executed.
+
+##### Params
+- <a href="#write.fd" name="write.fd"></a> `fd`: [`fd`](#fd)
+
+- <a href="#write.iovs" name="write.iovs"></a> `iovs`: [`ciovec_array`](#ciovec_array)
+List of scatter/gather vectors from which to retrieve data.
+
+##### Results
+- <a href="#write.error" name="write.error"></a> `error`: `Result<size, errno>`
+The number of bytes written.
+
+###### Variant Layout
+- size: 8
+- align: 4
+- tag_size: 4
+###### Variant cases
+- <a href="#write.error.ok" name="write.error.ok"></a> `ok`: [`size`](#size)
+
+- <a href="#write.error.err" name="write.error.err"></a> `err`: [`errno`](#errno)
+
diff --git a/standard/io/witx/io_arrays.witx b/standard/io/witx/io_arrays.witx
new file mode 100644
index 0000000..f6439c8
--- /dev/null
+++ b/standard/io/witx/io_arrays.witx
@@ -0,0 +1,49 @@
+;; WASI I/O Arrays.
+
+(use "typenames.witx")
+
+(module $wasi_ephemeral_io_arrays
+  ;;; Linear memory to be accessed by WASI functions that need it.
+  (import "memory" (memory))
+
+  ;;; Provide file advisory information on a file descriptor.
+  ;;; Note: This is similar to `posix_fadvise` in POSIX.
+  (@interface func (export "advise")
+    (param $fd $fd)
+    ;;; The offset within the file to which the advisory applies.
+    (param $offset $filesize)
+    ;;; The length of the region to which the advisory applies.
+    (param $len $filesize)
+    ;;; The advice.
+    (param $advice $advice)
+    (result $error (expected (error $errno)))
+  )
+
+  ;;; Read from a file descriptor, without using and updating the file descriptor's offset.
+  ;;; Note: This is similar to `preadv` in Linux (and other Unix-es).
+  (@interface func (export "pread")
+    (param $fd $fd)
+    ;;; List of scatter/gather vectors in which to store data.
+    (param $iovs $iovec_array)
+    ;;; The offset within the file at which to read.
+    (param $offset $filesize)
+    ;;; The number of bytes read.
+    (result $error (expected $size (error $errno)))
+  )
+
+  ;;; Write to a file descriptor, without using and updating the file descriptor's offset.
+  ;;; Note: This is similar to `pwritev` in Linux (and other Unix-es).
+  ;;;
+  ;;; Like Linux (and other Unix-es), any calls of `pwrite` (and other
+  ;;; functions to read or write) for a regular file by other threads in the
+  ;;; WASI process should not be interleaved while `pwrite` is executed.
+  (@interface func (export "pwrite")
+    (param $fd $fd)
+    ;;; List of scatter/gather vectors from which to retrieve data.
+    (param $iovs $ciovec_array)
+    ;;; The offset within the file at which to write.
+    (param $offset $filesize)
+    ;;; The number of bytes written.
+    (result $error (expected $size (error $errno)))
+  )
+)
diff --git a/standard/io/witx/io_streams.witx b/standard/io/witx/io_streams.witx
new file mode 100644
index 0000000..b762917
--- /dev/null
+++ b/standard/io/witx/io_streams.witx
@@ -0,0 +1,32 @@
+;; WASI I/O Streams.
+
+(use "typenames.witx")
+
+(module $wasi_ephemeral_io_streams
+  ;;; Linear memory to be accessed by WASI functions that need it.
+  (import "memory" (memory))
+
+  ;;; Read from a file descriptor.
+  ;;; Note: This is similar to `readv` in POSIX.
+  (@interface func (export "read")
+    (param $fd $fd)
+    ;;; List of scatter/gather vectors to which to store data.
+    (param $iovs $iovec_array)
+    ;;; The number of bytes read.
+    (result $error (expected $size (error $errno)))
+  )
+
+  ;;; Write to a file descriptor.
+  ;;; Note: This is similar to `writev` in POSIX.
+  ;;;
+  ;;; Like POSIX, any calls of `write` (and other functions to read or write)
+  ;;; for a regular file by other threads in the WASI process should not be
+  ;;; interleaved while `write` is executed.
+  (@interface func (export "write")
+    (param $fd $fd)
+    ;;; List of scatter/gather vectors from which to retrieve data.
+    (param $iovs $ciovec_array)
+    ;;; The number of bytes written.
+    (result $error (expected $size (error $errno)))
+  )
+)
diff --git a/standard/io/witx/typenames.witx b/standard/io/witx/typenames.witx
new file mode 100644
index 0000000..bbd6489
--- /dev/null
+++ b/standard/io/witx/typenames.witx
@@ -0,0 +1,708 @@
+;; Type names used by low-level WASI interfaces.
+;;
+;; Some content here is derived from [CloudABI](https://github.com/NuxiNL/cloudabi).
+;;
+;; This is a `witx` file. See [here](https://github.com/WebAssembly/WASI/tree/master/docs/witx.md)
+;; for an explanation of what that means.
+
+;;; An array size.
+;;;
+;;; Note: This is similar to `size_t` in POSIX.
+(typename $size (@witx usize))
+
+;;; Non-negative file size or length of a region within a file.
+(typename $filesize u64)
+
+;;; Timestamp in nanoseconds.
+(typename $timestamp u64)
+
+;;; Identifiers for clocks.
+(typename $clockid
+  (enum (@witx tag u32)
+    ;;; The clock measuring real time. Time value zero corresponds with
+    ;;; 1970-01-01T00:00:00Z.
+    $realtime
+    ;;; The store-wide monotonic clock, which is defined as a clock measuring
+    ;;; real time, whose value cannot be adjusted and which cannot have negative
+    ;;; clock jumps. The epoch of this clock is undefined. The absolute time
+    ;;; value of this clock therefore has no meaning.
+    $monotonic
+  )
+)
+
+;;; Error codes returned by functions.
+;;; Not all of these error codes are returned by the functions provided by this
+;;; API; some are used in higher-level library layers, and others are provided
+;;; merely for alignment with POSIX.
+(typename $errno
+  (enum (@witx tag u16)
+    ;;; No error occurred. System call completed successfully.
+    $success
+    ;;; Argument list too long.
+    $2big
+    ;;; Permission denied.
+    $access
+    ;;; Address in use.
+    $addrinuse
+    ;;; Address not available.
+    $addrnotavail
+    ;;; Address family not supported.
+    $afnosupport
+    ;;; Resource unavailable, or operation would block.
+    $again
+    ;;; Connection already in progress.
+    $already
+    ;;; Bad file descriptor.
+    $badf
+    ;;; Bad message.
+    $badmsg
+    ;;; Device or resource busy.
+    $busy
+    ;;; Operation canceled.
+    $canceled
+    ;;; No child processes.
+    $child
+    ;;; Connection aborted.
+    $connaborted
+    ;;; Connection refused.
+    $connrefused
+    ;;; Connection reset.
+    $connreset
+    ;;; Resource deadlock would occur.
+    $deadlk
+    ;;; Destination address required.
+    $destaddrreq
+    ;;; Mathematics argument out of domain of function.
+    $dom
+    ;;; Reserved.
+    $dquot
+    ;;; File exists.
+    $exist
+    ;;; Bad address.
+    $fault
+    ;;; File too large.
+    $fbig
+    ;;; Host is unreachable.
+    $hostunreach
+    ;;; Identifier removed.
+    $idrm
+    ;;; Illegal byte sequence.
+    $ilseq
+    ;;; Operation in progress.
+    $inprogress
+    ;;; Interrupted function.
+    $intr
+    ;;; Invalid argument.
+    $inval
+    ;;; I/O error.
+    $io
+    ;;; Socket is connected.
+    $isconn
+    ;;; Is a directory.
+    $isdir
+    ;;; Too many levels of symbolic links.
+    $loop
+    ;;; File descriptor value too large.
+    $mfile
+    ;;; Too many links.
+    $mlink
+    ;;; Message too large.
+    $msgsize
+    ;;; Reserved.
+    $multihop
+    ;;; Filename too long.
+    $nametoolong
+    ;;; Network is down.
+    $netdown
+    ;;; Connection aborted by network.
+    $netreset
+    ;;; Network unreachable.
+    $netunreach
+    ;;; Too many files open in system.
+    $nfile
+    ;;; No buffer space available.
+    $nobufs
+    ;;; No such device.
+    $nodev
+    ;;; No such file or directory.
+    $noent
+    ;;; Executable file format error.
+    $noexec
+    ;;; No locks available.
+    $nolck
+    ;;; Reserved.
+    $nolink
+    ;;; Not enough space.
+    $nomem
+    ;;; No message of the desired type.
+    $nomsg
+    ;;; Protocol not available.
+    $noprotoopt
+    ;;; No space left on device.
+    $nospc
+    ;;; Function not supported.
+    $nosys
+    ;;; The socket is not connected.
+    $notconn
+    ;;; Not a directory or a symbolic link to a directory.
+    $notdir
+    ;;; Directory not empty.
+    $notempty
+    ;;; State not recoverable.
+    $notrecoverable
+    ;;; Not a socket.
+    $notsock
+    ;;; Not supported, or operation not supported on socket.
+    $notsup
+    ;;; Inappropriate I/O control operation.
+    $notty
+    ;;; No such device or address.
+    $nxio
+    ;;; Value too large to be stored in data type.
+    $overflow
+    ;;; Previous owner died.
+    $ownerdead
+    ;;; Operation not permitted.
+    $perm
+    ;;; Broken pipe.
+    $pipe
+    ;;; Protocol error.
+    $proto
+    ;;; Protocol not supported.
+    $protonosupport
+    ;;; Protocol wrong type for socket.
+    $prototype
+    ;;; Result too large.
+    $range
+    ;;; Read-only file system.
+    $rofs
+    ;;; Invalid seek.
+    $spipe
+    ;;; No such process.
+    $srch
+    ;;; Reserved.
+    $stale
+    ;;; Connection timed out.
+    $timedout
+    ;;; Text file busy.
+    $txtbsy
+    ;;; Cross-device link.
+    $xdev
+    ;;; Extension: Capabilities insufficient.
+    $notcapable
+  )
+)
+
+;;; File descriptor rights, determining which actions may be performed.
+(typename $rights
+  (flags (@witx repr u64)
+    ;;; The right to invoke `fd_datasync`.
+    ;;
+    ;;; If `path_open` is set, includes the right to invoke
+    ;;; `path_open` with `fdflags::dsync`.
+    $fd_datasync
+    ;;; The right to invoke `fd_read` and `sock_recv`.
+    ;;
+    ;;; If `rights::fd_seek` is set, includes the right to invoke `fd_pread`.
+    $fd_read
+    ;;; The right to invoke `fd_seek`. This flag implies `rights::fd_tell`.
+    $fd_seek
+    ;;; The right to invoke `fd_fdstat_set_flags`.
+    $fd_fdstat_set_flags
+    ;;; The right to invoke `fd_sync`.
+    ;;
+    ;;; If `path_open` is set, includes the right to invoke
+    ;;; `path_open` with `fdflags::rsync` and `fdflags::dsync`.
+    $fd_sync
+    ;;; The right to invoke `fd_seek` in such a way that the file offset
+    ;;; remains unaltered (i.e., `whence::cur` with offset zero), or to
+    ;;; invoke `fd_tell`.
+    $fd_tell
+    ;;; The right to invoke `fd_write` and `sock_send`.
+    ;;; If `rights::fd_seek` is set, includes the right to invoke `fd_pwrite`.
+    $fd_write
+    ;;; The right to invoke `fd_advise`.
+    $fd_advise
+    ;;; The right to invoke `fd_allocate`.
+    $fd_allocate
+    ;;; The right to invoke `path_create_directory`.
+    $path_create_directory
+    ;;; If `path_open` is set, the right to invoke `path_open` with `oflags::create`.
+    $path_create_file
+    ;;; The right to invoke `path_link` with the file descriptor as the
+    ;;; source directory.
+    $path_link_source
+    ;;; The right to invoke `path_link` with the file descriptor as the
+    ;;; target directory.
+    $path_link_target
+    ;;; The right to invoke `path_open`.
+    $path_open
+    ;;; The right to invoke `fd_readdir`.
+    $fd_readdir
+    ;;; The right to invoke `path_readlink`.
+    $path_readlink
+    ;;; The right to invoke `path_rename` with the file descriptor as the source directory.
+    $path_rename_source
+    ;;; The right to invoke `path_rename` with the file descriptor as the target directory.
+    $path_rename_target
+    ;;; The right to invoke `path_filestat_get`.
+    $path_filestat_get
+    ;;; The right to change a file's size.
+    ;;; If `path_open` is set, includes the right to invoke `path_open` with `oflags::trunc`.
+    ;;; Note: there is no function named `path_filestat_set_size`. This follows POSIX design,
+    ;;; which only has `ftruncate` and does not provide `ftruncateat`.
+    ;;; While such function would be desirable from the API design perspective, there are virtually
+    ;;; no use cases for it since no code written for POSIX systems would use it.
+    ;;; Moreover, implementing it would require multiple syscalls, leading to inferior performance.
+    $path_filestat_set_size
+    ;;; The right to invoke `path_filestat_set_times`.
+    $path_filestat_set_times
+    ;;; The right to invoke `path_permissions_set`.
+    $path_permissions_set
+    ;;; The right to invoke `fd_filestat_get`.
+    $fd_filestat_get
+    ;;; The right to invoke `fd_filestat_set_size`.
+    $fd_filestat_set_size
+    ;;; The right to invoke `fd_filestat_set_times`.
+    $fd_filestat_set_times
+    ;;; The right to invoke `fd_permissions_set`.
+    $fd_permissions_set
+    ;;; The right to invoke `path_symlink`.
+    $path_symlink
+    ;;; The right to invoke `path_remove_directory`.
+    $path_remove_directory
+    ;;; The right to invoke `path_unlink_file`.
+    $path_unlink_file
+    ;;; If `rights::fd_read` is set, includes the right to invoke `poll_oneoff` to subscribe to `eventtype::fd_read`.
+    ;;; If `rights::fd_write` is set, includes the right to invoke `poll_oneoff` to subscribe to `eventtype::fd_write`.
+    $poll_fd_readwrite
+    ;;; The right to invoke `sock_shutdown`.
+    $sock_shutdown
+  )
+)
+
+;;; A file descriptor handle.
+(typename $fd (handle))
+
+;;; A region of memory for scatter/gather reads.
+(typename $iovec
+  (record
+    ;;; The address of the buffer to be filled.
+    (field $buf (@witx pointer u8))
+    ;;; The length of the buffer to be filled.
+    (field $buf_len $size)
+  )
+)
+
+;;; A region of memory for scatter/gather writes.
+(typename $ciovec
+  (record
+    ;;; The address of the buffer to be written.
+    (field $buf (@witx const_pointer u8))
+    ;;; The length of the buffer to be written.
+    (field $buf_len $size)
+  )
+)
+
+(typename $iovec_array (list $iovec))
+(typename $ciovec_array (list $ciovec))
+
+;;; Relative offset within a file.
+(typename $filedelta s64)
+
+;;; The position relative to which to set the offset of the file descriptor.
+(typename $whence
+  (enum (@witx tag u8)
+    ;;; Seek relative to start-of-file.
+    $set
+    ;;; Seek relative to current position.
+    $cur
+    ;;; Seek relative to end-of-file.
+    $end
+  )
+)
+
+;;; A reference to the offset of a directory entry.
+(typename $dircookie u64)
+
+;;; In an `fd_readdir` call, this value signifies the start of the directory.
+(@witx const $dircookie $start 0)
+
+;;; The type for the `dirent::d_namlen` field of `dirent`.
+(typename $dirnamlen u32)
+
+;;; File serial number that is unique within its file system.
+(typename $inode u64)
+
+;;; The type of a file descriptor or file.
+(typename $filetype
+  (enum (@witx tag u8)
+    ;;; The type of the file descriptor or file is unknown or is different from any of the other types specified.
+    $unknown
+    ;;; The file descriptor or file refers to a block device inode.
+    $block_device
+    ;;; The file descriptor or file refers to a character device inode.
+    $character_device
+    ;;; The file descriptor or file refers to a directory inode.
+    $directory
+    ;;; The file descriptor or file refers to a regular file inode.
+    $regular_file
+    ;;; The file descriptor or file refers to a datagram socket.
+    $socket_dgram
+    ;;; The file descriptor or file refers to a byte-stream socket.
+    $socket_stream
+    ;;; The file refers to a symbolic link inode.
+    $symbolic_link
+    ;;; The file descriptor or file refers to a FIFO.
+    $fifo
+  )
+)
+
+;;; A directory entry.
+(typename $dirent
+  (record
+    ;;; The offset of the next directory entry stored in this directory.
+    (field $d_next $dircookie)
+    ;;; The serial number of the file referred to by this directory entry.
+    (field $d_ino $inode)
+    ;;; The type of the file referred to by this directory entry.
+    (field $d_type $filetype)
+    ;;; The length of the name of the directory entry.
+    (field $d_namlen $dirnamlen)
+  )
+)
+
+;;; File or memory access pattern advisory information.
+(typename $advice
+  (enum (@witx tag u8)
+    ;;; The application has no advice to give on its behavior with respect to the specified data.
+    $normal
+    ;;; The application expects to access the specified data sequentially from lower offsets to higher offsets.
+    $sequential
+    ;;; The application expects to access the specified data in a random order.
+    $random
+    ;;; The application expects to access the specified data in the near future.
+    $willneed
+    ;;; The application expects that it will not access the specified data in the near future.
+    $dontneed
+    ;;; The application expects to access the specified data once and then not reuse it thereafter.
+    $noreuse
+  )
+)
+
+;;; File descriptor flags.
+(typename $fdflags
+  (flags (@witx repr u16)
+    ;;; Append mode: Data written to the file is always appended to the file's end.
+    $append
+    ;;; Write according to synchronized I/O data integrity completion. Only the data stored in the file is synchronized.
+    $dsync
+    ;;; Non-blocking mode.
+    $nonblock
+    ;;; Synchronized read I/O operations.
+    $rsync
+    ;;; Write according to synchronized I/O file integrity completion. In
+    ;;; addition to synchronizing the data stored in the file, the implementation
+    ;;; may also synchronously update the file's metadata.
+    $sync
+  )
+)
+
+;;; File descriptor attributes.
+(typename $fdstat
+  (record
+    ;;; File type.
+    (field $fs_filetype $filetype)
+    ;;; File descriptor flags.
+    (field $fs_flags $fdflags)
+    ;;; Rights that apply to this file descriptor.
+    (field $fs_rights_base $rights)
+    ;;; Maximum set of rights that may be installed on new file descriptors that
+    ;;; are created through this file descriptor, e.g., through `path_open`.
+    (field $fs_rights_inheriting $rights)
+  )
+)
+
+;;; Identifier for a device containing a file system. Can be used in combination
+;;; with `inode` to uniquely identify a file or directory in the filesystem.
+(typename $device u64)
+
+;;; Which file time attributes to adjust.
+(typename $fstflags
+  (flags (@witx repr u16)
+    ;;; Adjust the last data access timestamp to the value stored in `filestat::atim`.
+    $atim
+    ;;; Adjust the last data access timestamp to the time of clock `clockid::realtime`.
+    $atim_now
+    ;;; Adjust the last data modification timestamp to the value stored in `filestat::mtim`.
+    $mtim
+    ;;; Adjust the last data modification timestamp to the time of clock `clockid::realtime`.
+    $mtim_now
+  )
+)
+
+;;; Flags determining the method of how paths are resolved.
+(typename $lookupflags
+  (flags (@witx repr u32)
+    ;;; As long as the resolved path corresponds to a symbolic link, it is expanded.
+    $symlink_follow
+  )
+)
+
+;;; Open flags used by `path_open`.
+(typename $oflags
+  (flags (@witx repr u16)
+    ;;; Create file if it does not exist.
+    $create
+    ;;; Fail if not a directory.
+    $directory
+    ;;; Fail if file already exists.
+    $excl
+    ;;; Truncate file to size 0.
+    $trunc
+  )
+)
+
+;;; Number of hard links to an inode.
+(typename $linkcount u64)
+
+;;; File permissions. This represents the permissions associated with a
+;;; file in a filesystem, and don't fully reflect all the conditions
+;;; which determine whether a given WASI program can access the file.
+(typename $permissions
+  (flags (@witx repr u8)
+    ;;; For files, permission to read the file.
+    ;;; For directories, permission to do `readdir` and access files
+    ;;; within the directory.
+    ;;;
+    ;;; Note: This is similar to the read bit being set on files, and the
+    ;;; read *and* execute bits being set on directories, in POSIX.
+    $read
+
+    ;;; For files, permission to mutate the file.
+    ;;; For directories, permission to create, remove, and rename items
+    ;;; within the directory.
+    $write
+
+    ;;; For files, permission to "execute" the file, using whatever
+    ;;; concept of "executing" the host filesystem has.
+    ;;; This flag is not valid for directories.
+    $execute
+
+    ;;; For filesystems which have a concept of multiple "users", this flag
+    ;;; indicates that the file is only accessible by the effective "user"
+    ;;; that the WASI store uses to access the filesystem, and inaccessible
+    ;;; to other "users".
+    $private
+  )
+)
+
+;;; File attributes.
+(typename $filestat
+  (record
+    ;;; Device ID of device containing the file.
+    (field $dev $device)
+    ;;; File serial number.
+    (field $ino $inode)
+    ;;; File type.
+    (field $filetype $filetype)
+    ;;; File permissions.
+    (field $permissions $permissions)
+    ;;; Number of hard links to the file.
+    (field $nlink $linkcount)
+    ;;; For regular files, the file size in bytes. For symbolic links, the length in bytes of the pathname contained in the symbolic link.
+    (field $size $filesize)
+    ;;; Last data access timestamp.
+    (field $atim $timestamp)
+    ;;; Last data modification timestamp.
+    (field $mtim $timestamp)
+    ;;; Last file status change timestamp.
+    (field $ctim $timestamp)
+  )
+)
+
+;;; User-provided value that may be attached to objects that is retained when
+;;; extracted from the implementation.
+(typename $userdata u64)
+
+;;; Type of a subscription to an event or its occurrence.
+(typename $eventtype
+  (enum (@witx tag u8)
+    ;;; The time value of clock `subscription_clock::id` has
+    ;;; reached timestamp `subscription_clock::timeout`.
+    $clock
+    ;;; File descriptor `subscription_fd_readwrite::fd` has data
+    ;;; available for reading. This event always triggers for regular files.
+    $fd_read
+    ;;; File descriptor `subscription_fd_readwrite::fd` has capacity
+    ;;; available for writing. This event always triggers for regular files.
+    $fd_write
+  )
+)
+
+;;; The state of the file descriptor subscribed to with
+;;; `eventtype::fd_read` or `eventtype::fd_write`.
+(typename $eventrwflags
+  (flags (@witx repr u16)
+    ;;; The peer of this socket has closed or disconnected.
+    $fd_readwrite_hangup
+  )
+)
+
+;;; The contents of an `event` when type is `eventtype::fd_read` or
+;;; `eventtype::fd_write`.
+(typename $event_fd_readwrite
+  (record
+    ;;; The number of bytes available for reading or writing.
+    (field $nbytes $filesize)
+    ;;; The state of the file descriptor.
+    (field $flags $eventrwflags)
+  )
+)
+
+;;; The contents of an `event`.
+(typename $event_u
+  (variant (@witx tag $eventtype)
+    (case $fd_read $event_fd_readwrite)
+    (case $fd_write $event_fd_readwrite)
+    (case $clock)
+  )
+)
+
+;;; An event that occurred.
+(typename $event
+  (record
+    ;;; User-provided value that got attached to `subscription::userdata`.
+    (field $userdata $userdata)
+    ;;; If non-zero, an error that occurred while processing the subscription request.
+    (field $error $errno)
+    ;;; The type of the event that occurred, and the contents of the event
+    (field $u $event_u)
+  )
+)
+
+;;; Flags determining how to interpret the timestamp provided in
+;;; `subscription_clock::timeout`.
+(typename $subclockflags
+  (flags (@witx repr u16)
+    ;;; If set, treat the timestamp provided in
+    ;;; `subscription_clock::timeout` as an absolute timestamp of clock
+    ;;; `subscription_clock::id`. If clear, treat the timestamp
+    ;;; provided in `subscription_clock::timeout` relative to the
+    ;;; current time value of clock `subscription_clock::id`.
+    $subscription_clock_abstime
+  )
+)
+
+;;; The contents of a `subscription` when type is `eventtype::clock`.
+(typename $subscription_clock
+  (record
+    ;;; The clock against which to compare the timestamp.
+    (field $id $clockid)
+    ;;; The absolute or relative timestamp.
+    (field $timeout $timestamp)
+    ;;; The amount of time that the implementation may wait additionally
+    ;;; to coalesce with other events.
+    (field $precision $timestamp)
+    ;;; Flags specifying whether the timeout is absolute or relative
+    (field $flags $subclockflags)
+  )
+)
+
+;;; The contents of a `subscription` when type is type is
+;;; `eventtype::fd_read` or `eventtype::fd_write`.
+(typename $subscription_fd_readwrite
+  (record
+    ;;; The file descriptor on which to wait for it to become ready for reading or writing.
+    (field $fd $fd)
+  )
+)
+
+;;; The contents of a `subscription`.
+(typename $subscription_u
+  (union (@witx tag $eventtype)
+    $subscription_clock
+    $subscription_fd_readwrite
+    $subscription_fd_readwrite
+  )
+)
+
+;;; Subscription to an event.
+(typename $subscription
+  (record
+    ;;; User-provided value that is attached to the subscription in the
+    ;;; implementation and returned through `event::userdata`.
+    (field $userdata $userdata)
+    ;;; The type of the event to which to subscribe, and the contents of the subscription.
+    (field $u $subscription_u)
+  )
+)
+
+;;; Exit code generated by a program when exiting.
+(typename $exitcode u8)
+
+;;; Indicate the program exited successfully.
+;;;
+;;; Note: This is similar to `EXIT_SUCCESS` in POSIX.
+(@witx const $exitcode $success 0)
+
+;;; Indicate the program exited unsuccessfully.
+;;;
+;;; Note: This is similar to `EXIT_FAILURE` in POSIX.
+(@witx const $exitcode $failure 1)
+
+;;; Flags provided to `sock_recv`.
+(typename $riflags
+  (flags (@witx repr u16)
+    ;;; Returns the message without removing it from the socket's receive queue.
+    $recv_peek
+    ;;; On byte-stream sockets, block until the full amount of data can be returned.
+    $recv_waitall
+  )
+)
+
+;;; Flags returned by `sock_recv`.
+(typename $roflags
+  (flags (@witx repr u16)
+    ;;; Returned by `sock_recv`: Message data has been truncated.
+    $recv_data_truncated
+  )
+)
+
+;;; Flags provided to `sock_send`. As there are currently no flags
+;;; defined, it must be set to zero.
+(typename $siflags u16)
+
+;;; Which channels on a socket to shut down.
+(typename $sdflags
+  (flags (@witx repr u8)
+    ;;; Disables further receive operations.
+    $rd
+    ;;; Disables further send operations.
+    $wr
+  )
+)
+
+;;; Identifiers for preopened capabilities.
+(typename $preopentype
+  (enum (@witx tag u8)
+    ;;; A pre-opened directory.
+    $dir
+  )
+)
+
+;;; The contents of a `prestat` when its type is `preopentype::dir`.
+(typename $prestat_dir
+  (record
+    ;;; The length of the directory name for use with `fd_prestat_dir_name`.
+    (field $pr_name_len $size)
+  )
+)
+
+;;; Information about a pre-opened capability.
+(typename $prestat
+  (union (@witx tag $preopentype)
+    ;;; When type is `preopentype::dir`:
+    $prestat_dir
+  )
+)
diff --git a/tools/repo_docs.sh b/tools/repo_docs.sh
index e0187bc..76d1462 100755
--- a/tools/repo_docs.sh
+++ b/tools/repo_docs.sh
@@ -15,3 +15,8 @@ cargo run -p witx-cli -- docs $1 \
   ../../phases/ephemeral/witx/wasi_ephemeral_sched.witx \
   ../../phases/ephemeral/witx/wasi_ephemeral_sock.witx \
   --output ../../phases/ephemeral/docs.md
+
+for dir in ../../standard/*/witx; do
+  cargo run -p witx-cli -- docs $1 "$dir"/*.witx \
+    --output "$dir"/../docs.md
+done