1<!-- 2This document is derived from the file docs/cloudabi.md at revision 3af51ede669dbca0875d20893dae7f760b052b238 of the CloudABI repository 4hosted here: https://github.com/NuxiNL/cloudabi 5 6The upstream file bears the following notice, though note that the 7file is no longer generated, and contains significant edits: 8 9Copyright (c) 2016-2017 Nuxi (https://nuxi.nl/) and contributors. 10 11Redistribution and use in source and binary forms, with or without 12modification, are permitted provided that the following conditions 13are met: 141. Redistributions of source code must retain the above copyright 15 notice, this list of conditions and the following disclaimer. 162. Redistributions in binary form must reproduce the above copyright 17 notice, this list of conditions and the following disclaimer in the 18 documentation and/or other materials provided with the distribution. 19 20THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 21ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30SUCH DAMAGE. 31 32This file is automatically generated. Do not edit. 33 34Source: https://github.com/NuxiNL/cloudabi 35--> 36 37# WASI Core API 38 39This is the API-level documentation for WASI Core. The function names 40are prefixed with "\_\_wasi\_" to reflect how they are spelled in 41flat-namespace contexts, however at the wasm module level, they are 42unprefixed, because they're inside a module namespace (currently 43"wasi\_unstable"). 44 45Functions that start with `__wasi_fd_` operate on file descriptors, 46while functions that start with `__wasi_path_` operate on filesystem 47paths, which are relative to directory file descriptors. 48 49Much inspiration and content here is derived from [CloudABI] and [POSIX], 50though there are also several differences from CloudABI and POSIX. For 51example, WASI Core has no concept of processes in the traditional Unix 52sense. While wasm linear memories have some of the aspects of processes, 53and it's possible to *emulate* the full semantics of processes on top of 54them, this can sometimes be unnatural and inefficient. The goal for 55WASI Core is to be a WebAssembly-native API that exposes APIs that fit 56well into the underlying WebAssembly platform, rather than to directly 57emulate other platforms. 58 59This is also a work in progress, and the API here is still evolving. 60 61[CloudABI]: https://github.com/NuxiNL/cloudabi 62[POSIX]: http://pubs.opengroup.org/onlinepubs/9699919799/ 63 64## System calls 65 66- [`__wasi_args_get()`](#args_get) 67- [`__wasi_args_sizes_get()`](#args_sizes_get) 68- [`__wasi_clock_res_get()`](#clock_res_get) 69- [`__wasi_clock_time_get()`](#clock_time_get) 70- [`__wasi_environ_get()`](#environ_get) 71- [`__wasi_environ_sizes_get()`](#environ_sizes_get) 72- [`__wasi_fd_advise()`](#fd_advise) 73- [`__wasi_fd_allocate()`](#fd_allocate) 74- [`__wasi_fd_close()`](#fd_close) 75- [`__wasi_fd_datasync()`](#fd_datasync) 76- [`__wasi_fd_fdstat_get()`](#fd_fdstat_get) 77- [`__wasi_fd_fdstat_set_flags()`](#fd_fdstat_set_flags) 78- [`__wasi_fd_fdstat_set_rights()`](#fd_fdstat_set_rights) 79- [`__wasi_fd_filestat_get()`](#fd_filestat_get) 80- [`__wasi_fd_filestat_set_size()`](#fd_filestat_set_size) 81- [`__wasi_fd_filestat_set_times()`](#fd_filestat_set_times) 82- [`__wasi_fd_pread()`](#fd_pread) 83- [`__wasi_fd_prestat_get()`](#fd_prestat_get) 84- [`__wasi_fd_prestat_dir_name()`](#fd_prestat_dir_name) 85- [`__wasi_fd_pwrite()`](#fd_pwrite) 86- [`__wasi_fd_read()`](#fd_read) 87- [`__wasi_fd_readdir()`](#fd_readdir) 88- [`__wasi_fd_renumber()`](#fd_renumber) 89- [`__wasi_fd_seek()`](#fd_seek) 90- [`__wasi_fd_sync()`](#fd_sync) 91- [`__wasi_fd_tell()`](#fd_tell) 92- [`__wasi_fd_write()`](#fd_write) 93- [`__wasi_path_create_directory()`](#path_create_directory) 94- [`__wasi_path_filestat_get()`](#path_filestat_get) 95- [`__wasi_path_filestat_set_times()`](#path_filestat_set_times) 96- [`__wasi_path_link()`](#path_link) 97- [`__wasi_path_open()`](#path_open) 98- [`__wasi_path_readlink()`](#path_readlink) 99- [`__wasi_path_remove_directory()`](#path_remove_directory) 100- [`__wasi_path_rename()`](#path_rename) 101- [`__wasi_path_symlink()`](#path_symlink) 102- [`__wasi_path_unlink_file()`](#path_unlink_file) 103- [`__wasi_poll_oneoff()`](#poll_oneoff) 104- [`__wasi_proc_exit()`](#proc_exit) 105- [`__wasi_proc_raise()`](#proc_raise) 106- [`__wasi_random_get()`](#random_get) 107- [`__wasi_sched_yield()`](#sched_yield) 108- [`__wasi_sock_recv()`](#sock_recv) 109- [`__wasi_sock_send()`](#sock_send) 110- [`__wasi_sock_shutdown()`](#sock_shutdown) 111 112### <a href="#args_get" name="args_get"></a>`__wasi_args_get()` 113 114Read command-line argument data. 115 116The sizes of the buffers should match that returned by [`__wasi_args_sizes_get()`](#args_sizes_get). 117 118Inputs: 119 120- <a href="#args_get.argv" name="args_get.argv"></a><code>char \*\*<strong>argv</strong></code> 121 122 A pointer to a buffer to write the argument pointers. 123 124- <a href="#args_get.argv_buf" name="args_get.argv_buf"></a><code>char \*<strong>argv\_buf</strong></code> 125 126 A pointer to a buffer to write the argument string data. 127 128### <a href="#args_sizes_get" name="args_sizes_get"></a>`__wasi_args_sizes_get()` 129 130Return command-line argument data sizes. 131 132Outputs: 133 134- <a href="#args_sizes_get.argc" name="args_sizes_get.argc"></a><code>size\_t \*<strong>argc</strong></code> 135 136 The number of arguments. 137 138- <a href="#args_sizes_get.argv_buf_size" name="args_sizes_get.argv_buf_size"></a><code>size\_t \*<strong>argv\_buf\_size</strong></code> 139 140 The size of the argument string data. 141 142### <a href="#clock_res_get" name="clock_res_get"></a>`__wasi_clock_res_get()` 143 144Return the resolution of a clock. 145 146Implementations are required to provide a non-zero value for supported clocks. 147For unsupported clocks, return [`__WASI_EINVAL`](#errno.inval). 148 149Note: This is similar to `clock_getres` in POSIX. 150 151Inputs: 152 153- <a href="#clock_res_get.clock_id" name="clock_res_get.clock_id"></a><code>[\_\_wasi\_clockid\_t](#clockid) <strong>clock\_id</strong></code> 154 155 The clock for which to return the resolution. 156 157Outputs: 158 159- <a href="#clock_res_get.resolution" name="clock_res_get.resolution"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>resolution</strong></code> 160 161 The resolution of the clock. 162 163### <a href="#clock_time_get" name="clock_time_get"></a>`__wasi_clock_time_get()` 164 165Return the time value of a clock. 166 167Note: This is similar to `clock_gettime` in POSIX. 168 169Inputs: 170 171- <a href="#clock_time_get.clock_id" name="clock_time_get.clock_id"></a><code>[\_\_wasi\_clockid\_t](#clockid) <strong>clock\_id</strong></code> 172 173 The clock for which to return the time. 174 175- <a href="#clock_time_get.precision" name="clock_time_get.precision"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>precision</strong></code> 176 177 The maximum lag (exclusive) that the returned 178 time value may have, compared to its actual 179 value. 180 181Outputs: 182 183- <a href="#clock_time_get.time" name="clock_time_get.time"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>time</strong></code> 184 185 The time value of the clock. 186 187### <a href="#environ_get" name="environ_get"></a>`__wasi_environ_get()` 188 189Read environment variable data. 190 191The sizes of the buffers should match that returned by [`__wasi_environ_sizes_get()`](#environ_sizes_get). 192 193Inputs: 194 195- <a href="#environ_get.environ" name="environ_get.environ"></a><code>char \*\*<strong>environ</strong></code> 196 197 A pointer to a buffer to write the environment variable pointers. 198 199- <a href="#environ_get.environ_buf" name="environ_get.environ_buf"></a><code>char \*<strong>environ\_buf</strong></code> 200 201 A pointer to a buffer to write the environment variable string data. 202 203### <a href="#environ_sizes_get" name="environ_sizes_get"></a>`__wasi_environ_sizes_get()` 204 205Return command-line argument data sizes. 206 207Outputs: 208 209- <a href="#environ_sizes_get.environ_count" name="environ_sizes_get.environ_count"></a><code>size\_t \*<strong>environ\_count</strong></code> 210 211 The number of environment variables. 212 213- <a href="#environ_sizes_get.environ_buf_size" name="environ_sizes_get.environ_buf_size"></a><code>size\_t \*<strong>environ\_buf\_size</strong></code> 214 215 The size of the environment variable string data. 216 217### <a href="#fd_advise" name="fd_advise"></a>`__wasi_fd_advise()` 218 219Provide file advisory information on a file descriptor. 220 221Note: This is similar to `posix_fadvise` in POSIX. 222 223Inputs: 224 225- <a href="#fd_advise.fd" name="fd_advise.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 226 227 The file descriptor for the file for which to provide file advisory information. 228 229- <a href="#fd_advise.offset" name="fd_advise.offset"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>offset</strong></code> 230 231 The offset within the file to which the advisory applies. 232 233- <a href="#fd_advise.len" name="fd_advise.len"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>len</strong></code> 234 235 The length of the region to which the advisory applies. 236 237- <a href="#fd_advise.advice" name="fd_advise.advice"></a><code>[\_\_wasi\_advice\_t](#advice) <strong>advice</strong></code> 238 239 The advice. 240 241### <a href="#fd_allocate" name="fd_allocate"></a>`__wasi_fd_allocate()` 242 243Force the allocation of space in a file. 244 245Note: This is similar to `posix_fallocate` in POSIX. 246 247Inputs: 248 249- <a href="#fd_allocate.fd" name="fd_allocate.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 250 251 The file descriptor for the file in which to allocate space. 252 253- <a href="#fd_allocate.offset" name="fd_allocate.offset"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>offset</strong></code> 254 255 The offset at which to start the allocation. 256 257- <a href="#fd_allocate.len" name="fd_allocate.len"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>len</strong></code> 258 259 The length of the area that is allocated. 260 261### <a href="#fd_close" name="fd_close"></a>`__wasi_fd_close()` 262 263Close a file descriptor. 264 265Note: This is similar to `close` in POSIX. 266 267Inputs: 268 269- <a href="#fd_close.fd" name="fd_close.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 270 271 The file descriptor to close. 272 273### <a href="#fd_datasync" name="fd_datasync"></a>`__wasi_fd_datasync()` 274 275Synchronize the data of a file to disk. 276 277Note: This is similar to `fdatasync` in POSIX. 278 279Inputs: 280 281- <a href="#fd_datasync.fd" name="fd_datasync.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 282 283 The file descriptor of the file to synchronize to disk. 284 285### <a href="#fd_fdstat_get" name="fd_fdstat_get"></a>`__wasi_fd_fdstat_get()` 286 287Get the attributes of a file descriptor. 288 289Note: This returns similar flags to `fsync(fd, F_GETFL)` in POSIX, as well 290as additional fields. 291 292Inputs: 293 294- <a href="#fd_fdstat_get.fd" name="fd_fdstat_get.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 295 296 The file descriptor to inspect. 297 298- <a href="#fd_fdstat_get.buf" name="fd_fdstat_get.buf"></a><code>[\_\_wasi\_fdstat\_t](#fdstat) \*<strong>buf</strong></code> 299 300 The buffer where the file descriptor's attributes are stored. 301 302### <a href="#fd_fdstat_set_flags" name="fd_fdstat_set_flags"></a>`__wasi_fd_fdstat_set_flags()` 303 304Adjust the flags associated with a file descriptor. 305 306Note: This is similar to `fcntl(fd, F_SETFL, flags)` in POSIX. 307 308Inputs: 309 310- <a href="#fd_fdstat_set_flags.fd" name="fd_fdstat_set_flags.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 311 312 The file descriptor to operate on. 313 314- <a href="#fd_fdstat_set_flags.flags" name="fd_fdstat_set_flags.flags"></a><code>[\_\_wasi\_fdflags\_t](#fdflags) <strong>flags</strong></code> 315 316 The desired values of the file descriptor 317 flags. 318 319### <a href="#fd_fdstat_set_rights" name="fd_fdstat_set_rights"></a>`__wasi_fd_fdstat_set_rights()` 320 321Adjust the rights associated with a file descriptor. 322 323This can only be used to remove rights, and returns 324[`__WASI_ENOTCAPABLE`](#errno.notcapable) if called in a way that would attempt 325to add rights. 326 327Inputs: 328 329- <a href="#fd_fdstat_set_rights.fd" name="fd_fdstat_set_rights.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 330 331 The file descriptor to operate on. 332 333- <a href="#fd_fdstat_set_rights.fs_rights_base" name="fd_fdstat_set_rights.fs_rights_base"></a><code>[\_\_wasi\_rights\_t](#rights) <strong>fs\_rights\_base</strong></code> and <a href="#fd_fdstat_set_rights.fs_rights_inheriting" name="fd_fdstat_set_rights.fs_rights_inheriting"></a><code>[\_\_wasi\_rights\_t](#rights) <strong>fs\_rights\_inheriting</strong></code> 334 335 The desired rights of the file descriptor. 336 337### <a href="#fd_filestat_get" name="fd_filestat_get"></a>`__wasi_fd_filestat_get()` 338 339Return the attributes of an open file. 340 341Inputs: 342 343- <a href="#fd_filestat_get.fd" name="fd_filestat_get.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 344 345 The file descriptor to inspect. 346 347- <a href="#fd_filestat_get.buf" name="fd_filestat_get.buf"></a><code>[\_\_wasi\_filestat\_t](#filestat) \*<strong>buf</strong></code> 348 349 The buffer where the file's attributes are 350 stored. 351 352### <a href="#fd_filestat_set_size" name="fd_filestat_set_size"></a>`__wasi_fd_filestat_set_size()` 353 354Adjust the size of an open file. If this increases the file's size, the extra 355bytes are filled with zeros. 356 357Note: This is similar to `ftruncate` in POSIX. 358 359Inputs: 360 361- <a href="#fd_filestat_set_size.fd" name="fd_filestat_set_size.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 362 363 A file descriptor for the file to adjust. 364 365- <a href="#fd_filestat_set_size.st_size" name="fd_filestat_set_size.st_size"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>st\_size</strong></code> 366 367 The desired file size. 368 369### <a href="#fd_filestat_set_times" name="fd_filestat_set_times"></a>`__wasi_fd_filestat_set_times()` 370 371Adjust the timestamps of an open file or directory. 372 373Note: This is similar to `futimens` in POSIX. 374 375Inputs: 376 377- <a href="#fd_filestat_set_times.fd" name="fd_filestat_set_times.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 378 379 The file descriptor to operate on. 380 381- <a href="#fd_filestat_set_times.st_atim" name="fd_filestat_set_times.st_atim"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>st\_atim</strong></code> 382 383 The desired values of the data access timestamp. 384 385- <a href="#fd_filestat_set_times.st_mtim" name="fd_filestat_set_times.st_mtim"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>st\_mtim</strong></code> 386 387 The desired values of the data modification timestamp. 388 389- <a href="#fd_filestat_set_times.fst_flags" name="fd_filestat_set_times.fst_flags"></a><code>[\_\_wasi\_fstflags\_t](#fstflags) <strong>fst\_flags</strong></code> 390 391 A bitmask indicating which timestamps to adjust. 392 393### <a href="#fd_pread" name="fd_pread"></a>`__wasi_fd_pread()` 394 395Read from a file descriptor, without using and updating the 396file descriptor's offset. 397 398Note: This is similar to `preadv` in POSIX. 399 400Inputs: 401 402- <a href="#fd_pread.fd" name="fd_pread.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 403 404 The file descriptor from which to read data. 405 406- <a href="#fd_pread.iovs" name="fd_pread.iovs"></a><code>const [\_\_wasi\_iovec\_t](#iovec) \*<strong>iovs</strong></code> and <a href="#fd_pread.iovs_len" name="fd_pread.iovs_len"></a><code>size\_t <strong>iovs\_len</strong></code> 407 408 List of scatter/gather vectors in which to store data. 409 410- <a href="#fd_pread.offset" name="fd_pread.offset"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>offset</strong></code> 411 412 The offset within the file at which to read. 413 414Outputs: 415 416- <a href="#fd_pread.nread" name="fd_pread.nread"></a><code>size\_t <strong>nread</strong></code> 417 418 The number of bytes read. 419 420### <a href="#fd_prestat_get" name="fd_prestat_get"></a>`__wasi_fd_prestat_get()` 421 422Return a description of the given preopened file descriptor. 423 424Inputs: 425 426- <a href="#fd_prestat_get.fd" name="fd_prestat_get.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 427 428 The file descriptor about which to retrieve information. 429 430- <a href="#fd_prestat_get.buf" name="fd_prestat_get.buf"></a><code>[\_\_wasi\_prestat\_t](#prestat) \*<strong>buf</strong></code> 431 432 The buffer where the description is stored. 433 434### <a href="#fd_prestat_dir_name" name="fd_prestat_dir_name"></a>`__wasi_fd_prestat_dir_name()` 435 436Return a description of the given preopened file descriptor. 437 438Inputs: 439 440- <a href="#fd_prestat_dir_name.fd" name="fd_prestat_dir_name.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 441 442 The file descriptor about which to retrieve information. 443 444- <a href="#fd_prestat_dir_name.path" name="fd_prestat_dir_name.path"></a><code>const char \*<strong>path</strong></code> and <a href="#fd_prestat_dir_name.path_len" name="fd_prestat_dir_name.path_len"></a><code>size\_t <strong>path\_len</strong></code> 445 446 A buffer into which to write the preopened directory name. 447 448### <a href="#fd_pwrite" name="fd_pwrite"></a>`__wasi_fd_pwrite()` 449 450Write to a file descriptor, without using and updating the 451file descriptor's offset. 452 453Note: This is similar to `pwritev` in POSIX. 454 455Inputs: 456 457- <a href="#fd_pwrite.fd" name="fd_pwrite.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 458 459 The file descriptor to which to write data. 460 461- <a href="#fd_pwrite.iovs" name="fd_pwrite.iovs"></a><code>const [\_\_wasi\_ciovec\_t](#ciovec) \*<strong>iovs</strong></code> and <a href="#fd_pwrite.iovs_len" name="fd_pwrite.iovs_len"></a><code>size\_t <strong>iovs\_len</strong></code> 462 463 List of scatter/gather vectors from which to retrieve data. 464 465- <a href="#fd_pwrite.offset" name="fd_pwrite.offset"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>offset</strong></code> 466 467 The offset within the file at which to write. 468 469Outputs: 470 471- <a href="#fd_pwrite.nwritten" name="fd_pwrite.nwritten"></a><code>size\_t <strong>nwritten</strong></code> 472 473 The number of bytes written. 474 475### <a href="#fd_read" name="fd_read"></a>`__wasi_fd_read()` 476 477Read from a file descriptor. 478 479Note: This is similar to `readv` in POSIX. 480 481Inputs: 482 483- <a href="#fd_read.fd" name="fd_read.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 484 485 The file descriptor from which to read data. 486 487- <a href="#fd_read.iovs" name="fd_read.iovs"></a><code>const [\_\_wasi\_iovec\_t](#iovec) \*<strong>iovs</strong></code> and <a href="#fd_read.iovs_len" name="fd_read.iovs_len"></a><code>size\_t <strong>iovs\_len</strong></code> 488 489 List of scatter/gather vectors to which to store data. 490 491Outputs: 492 493- <a href="#fd_read.nread" name="fd_read.nread"></a><code>size\_t <strong>nread</strong></code> 494 495 The number of bytes read. 496 497### <a href="#fd_readdir" name="fd_readdir"></a>`__wasi_fd_readdir()` 498 499Read directory entries from a directory. 500 501When successful, the contents of the output buffer consist of 502a sequence of directory entries. Each directory entry consists 503of a [`__wasi_dirent_t`](#dirent) object, followed by [`__wasi_dirent_t::d_namlen`](#dirent.d_namlen) bytes 504holding the name of the directory entry. 505 506This function fills the output buffer as much as possible, 507potentially truncating the last directory entry. This allows 508the caller to grow its read buffer size in case it's too small 509to fit a single large directory entry, or skip the oversized 510directory entry. 511 512Inputs: 513 514- <a href="#fd_readdir.fd" name="fd_readdir.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 515 516 The directory from which to read the directory 517 entries. 518 519- <a href="#fd_readdir.buf" name="fd_readdir.buf"></a><code>void \*<strong>buf</strong></code> and <a href="#fd_readdir.buf_len" name="fd_readdir.buf_len"></a><code>size\_t <strong>buf\_len</strong></code> 520 521 The buffer where directory entries are stored. 522 523- <a href="#fd_readdir.cookie" name="fd_readdir.cookie"></a><code>[\_\_wasi\_dircookie\_t](#dircookie) <strong>cookie</strong></code> 524 525 The location within the directory to start 526 reading. 527 528Outputs: 529 530- <a href="#fd_readdir.bufused" name="fd_readdir.bufused"></a><code>size\_t <strong>bufused</strong></code> 531 532 The number of bytes stored in the read buffer. 533 If less than the size of the read buffer, the 534 end of the directory has been reached. 535 536### <a href="#fd_renumber" name="fd_renumber"></a>`__wasi_fd_renumber()` 537 538Atomically replace a file descriptor by renumbering another 539file descriptor. 540 541Due to the strong focus on thread safety, this environment 542does not provide a mechanism to duplicate or renumber a file 543descriptor to an arbitrary number, like dup2(). This would be 544prone to race conditions, as an actual file descriptor with the 545same number could be allocated by a different thread at the same 546time. 547 548This function provides a way to atomically renumber file 549descriptors, which would disappear if dup2() were to be 550removed entirely. 551 552Inputs: 553 554- <a href="#fd_renumber.from" name="fd_renumber.from"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>from</strong></code> 555 556 The file descriptor to renumber. 557 558- <a href="#fd_renumber.to" name="fd_renumber.to"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>to</strong></code> 559 560 The file descriptor to overwrite. 561 562### <a href="#fd_seek" name="fd_seek"></a>`__wasi_fd_seek()` 563 564Move the offset of a file descriptor. 565 566Note: This is similar to `lseek` in POSIX. 567 568Inputs: 569 570- <a href="#fd_seek.fd" name="fd_seek.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 571 572 The file descriptor to operate on. 573 574- <a href="#fd_seek.offset" name="fd_seek.offset"></a><code>[\_\_wasi\_filedelta\_t](#filedelta) <strong>offset</strong></code> 575 576 The number of bytes to move. 577 578- <a href="#fd_seek.whence" name="fd_seek.whence"></a><code>[\_\_wasi\_whence\_t](#whence) <strong>whence</strong></code> 579 580 The base from which the offset is relative. 581 582Outputs: 583 584- <a href="#fd_seek.newoffset" name="fd_seek.newoffset"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>newoffset</strong></code> 585 586 The new offset of the file descriptor, 587 relative to the start of the file. 588 589### <a href="#fd_sync" name="fd_sync"></a>`__wasi_fd_sync()` 590 591Synchronize the data and metadata of a file to disk. 592 593Note: This is similar to `fsync` in POSIX. 594 595Inputs: 596 597- <a href="#fd_sync.fd" name="fd_sync.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 598 599 The file descriptor of the file containing the data 600 and metadata to synchronize to disk. 601 602### <a href="#fd_tell" name="fd_tell"></a>`__wasi_fd_tell()` 603 604Return the current offset of a file descriptor. 605 606Note: This is similar to `lseek(fd, 0, SEEK_CUR)` in POSIX. 607 608Inputs: 609 610- <a href="#fd_tell.fd" name="fd_tell.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 611 612 The file descriptor to inspect. 613 614Outputs: 615 616- <a href="#fd_tell.offset" name="fd_tell.offset"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>offset</strong></code> 617 618 The current offset of the file descriptor, relative to the start of the file. 619 620### <a href="#fd_write" name="fd_write"></a>`__wasi_fd_write()` 621 622Write to a file descriptor. 623 624Note: This is similar to `writev` in POSIX. 625 626Inputs: 627 628- <a href="#fd_write.fd" name="fd_write.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 629 630 The file descriptor to which to write data. 631 632- <a href="#fd_write.iovs" name="fd_write.iovs"></a><code>const [\_\_wasi\_ciovec\_t](#ciovec) \*<strong>iovs</strong></code> and <a href="#fd_write.iovs_len" name="fd_write.iovs_len"></a><code>size\_t <strong>iovs\_len</strong></code> 633 634 List of scatter/gather vectors from which to retrieve data. 635 636Outputs: 637 638- <a href="#fd_write.nwritten" name="fd_write.nwritten"></a><code>size\_t <strong>nwritten</strong></code> 639 640 The number of bytes written. 641 642### <a href="#path_create_directory" name="path_create_directory"></a>`__wasi_path_create_directory()` 643 644Create a directory. 645 646Note: This is similar to `mkdirat` in POSIX. 647 648Inputs: 649 650- <a href="#path_create_directory.fd" name="path_create_directory.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 651 652 The working directory at which the resolution of the path starts. 653 654- <a href="#path_create_directory.path" name="path_create_directory.path"></a><code>const char \*<strong>path</strong></code> and <a href="#path_create_directory.path_len" name="path_create_directory.path_len"></a><code>size\_t <strong>path\_len</strong></code> 655 656 The path at which to create the directory. 657 658### <a href="#path_filestat_get" name="path_filestat_get"></a>`__wasi_path_filestat_get()` 659 660Return the attributes of a file or directory. 661 662Note: This is similar to `stat` in POSIX. 663 664Inputs: 665 666- <a href="#path_filestat_get.fd" name="path_filestat_get.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 667 668 The working directory at which the resolution of the path starts. 669 670- <a href="#path_filestat_get.flags" name="path_filestat_get.flags"></a><code>[\_\_wasi\_lookupflags\_t](#lookupflags) <strong>flags</strong></code> 671 672 Flags determining the method of how the path is resolved. 673 674- <a href="#path_filestat_get.path" name="path_filestat_get.path"></a><code>const char \*<strong>path</strong></code> and <a href="#path_filestat_get.path_len" name="path_filestat_get.path_len"></a><code>size\_t <strong>path\_len</strong></code> 675 676 The path of the file or directory to inspect. 677 678- <a href="#path_filestat_get.buf" name="path_filestat_get.buf"></a><code>[\_\_wasi\_filestat\_t](#filestat) \*<strong>buf</strong></code> 679 680 The buffer where the file's attributes are 681 stored. 682 683### <a href="#path_filestat_set_times" name="path_filestat_set_times"></a>`__wasi_path_filestat_set_times()` 684 685Adjust the timestamps of a file or directory. 686 687Note: This is similar to `utimensat` in POSIX. 688 689Inputs: 690 691- <a href="#path_filestat_set_times.fd" name="path_filestat_set_times.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 692 693 The working directory at which the resolution of the path starts. 694 695- <a href="#path_filestat_set_times.flags" name="path_filestat_set_times.flags"></a><code>[\_\_wasi\_lookupflags\_t](#lookupflags) <strong>flags</strong></code> 696 697 Flags determining the method of how the path is resolved. 698 699- <a href="#path_filestat_set_times.path" name="path_filestat_set_times.path"></a><code>const char \*<strong>path</strong></code> and <a href="#path_filestat_set_times.path_len" name="path_filestat_set_times.path_len"></a><code>size\_t <strong>path\_len</strong></code> 700 701 The path of the file or directory to operate on. 702 703- <a href="#path_filestat_set_times.st_atim" name="path_filestat_set_times.st_atim"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>st\_atim</strong></code> 704 705 The desired values of the data access timestamp. 706 707- <a href="#path_filestat_set_times.st_mtim" name="path_filestat_set_times.st_mtim"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>st\_mtim</strong></code> 708 709 The desired values of the data modification timestamp. 710 711- <a href="#path_filestat_set_times.fst_flags" name="path_filestat_set_times.fst_flags"></a><code>[\_\_wasi\_fstflags\_t](#fstflags) <strong>fst\_flags</strong></code> 712 713 A bitmask indicating which timestamps to adjust. 714 715### <a href="#path_link" name="path_link"></a>`__wasi_path_link()` 716 717Create a hard link. 718 719Note: This is similar to `linkat` in POSIX. 720 721Inputs: 722 723- <a href="#path_link.old_fd" name="path_link.old_fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>old\_fd</strong></code> 724 725 The working directory at which the resolution of the old path starts. 726 727- <a href="#path_link.old_flags" name="path_link.old_flags"></a><code>[\_\_wasi\_lookupflags\_t](#lookupflags) <strong>old\_flags</strong></code> 728 729 Flags determining the method of how the path is resolved. 730 731- <a href="#path_link.old_path" name="path_link.old_path"></a><code>const char \*<strong>old\_path</strong></code> and <a href="#path_link.old_path_len" name="path_link.old_path_len"></a><code>size\_t <strong>old\_path\_len</strong></code> 732 733 The source path from which to link. 734 735- <a href="#path_link.new_fd" name="path_link.new_fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>new\_fd</strong></code> 736 737 The working directory at which the resolution of the new path starts. 738 739- <a href="#path_link.new_path" name="path_link.new_path"></a><code>const char \*<strong>new\_path</strong></code> and <a href="#path_link.new_path_len" name="path_link.new_path_len"></a><code>size\_t <strong>new\_path\_len</strong></code> 740 741 The destination path at which to create the hard link. 742 743### <a href="#path_open" name="path_open"></a>`__wasi_path_open()` 744 745Open a file or directory. 746 747Note: This is similar to `openat` in POSIX. 748 749Inputs: 750 751- <a href="#path_open.dirfd" name="path_open.dirfd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>dirfd</strong></code> 752 753 The working directory at which the resolution of the path starts. 754 755- <a href="#path_open.dirflags" name="path_open.dirflags"></a><code>[\_\_wasi\_lookupflags\_t](#lookupflags) <strong>dirflags</strong></code> 756 757 Flags determining the method of how the path is resolved. 758 759- <a href="#path_open.path" name="path_open.path"></a><code>const char \*<strong>path</strong></code> and <a href="#path_open.path_len" name="path_open.path_len"></a><code>size\_t <strong>path\_len</strong></code> 760 761 The path of the file or directory to open. 762 763- <a href="#path_open.o_flags" name="path_open.o_flags"></a><code>[\_\_wasi\_oflags\_t](#oflags) <strong>o_flags</strong></code> 764 765 The method by which to open the file. 766 767- <a href="#path_open.fs_rights_base" name="path_open.fs_rights_base"></a><code>[\_\_wasi\_rights\_t](#rights) <strong>fs\_rights\_base</strong></code> and <a href="#path_open.fs_rights_inheriting" name="path_open.fs_rights_inheriting"></a><code>[\_\_wasi\_rights\_t](#rights) <strong>fs\_rights\_inheriting</strong></code> 768 769 The initial rights of the newly created file descriptor. The 770 implementation is allowed to return a file descriptor with fewer 771 rights than specified, if and only if those rights do not apply 772 to the type of file being opened. 773 774 The *base* rights are rights that will apply to operations using 775 the file descriptor itself, while the *inheriting* rights are 776 rights that apply to file descriptors derived from it. 777 778- <a href="#path_open.fs_flags" name="path_open.fs_flags"></a><code>[\_\_wasi\_fdflags\_t](#fdflags) <strong>fs\_flags</strong></code> 779 780 The initial flags of the file descriptor. 781 782Outputs: 783 784- <a href="#path_open.fd" name="path_open.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 785 786 The file descriptor of the file that has been 787 opened. 788 789### <a href="#path_readlink" name="path_readlink"></a>`__wasi_path_readlink()` 790 791Read the contents of a symbolic link. 792 793Note: This is similar to `readlinkat` in POSIX. 794 795Inputs: 796 797- <a href="#path_readlink.fd" name="path_readlink.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 798 799 The working directory at which the resolution of the path starts. 800 801- <a href="#path_readlink.path" name="path_readlink.path"></a><code>const char \*<strong>path</strong></code> and <a href="#path_readlink.path_len" name="path_readlink.path_len"></a><code>size\_t <strong>path\_len</strong></code> 802 803 The path of the symbolic link from which to read. 804 805- <a href="#path_readlink.buf" name="path_readlink.buf"></a><code>char \*<strong>buf</strong></code> and <a href="#path_readlink.buf_len" name="path_readlink.buf_len"></a><code>size\_t <strong>buf\_len</strong></code> 806 807 The buffer to which to write the contents of the symbolic link. 808 809Outputs: 810 811- <a href="#path_readlink.bufused" name="path_readlink.bufused"></a><code>size\_t <strong>bufused</strong></code> 812 813 The number of bytes placed in the buffer. 814 815### <a href="#path_remove_directory" name="path_remove_directory"></a>`__wasi_path_remove_directory()` 816 817Remove a directory. 818 819Return [`__WASI_ENOTEMPTY`](#errno.notempty) if the directory is not empty. 820 821Note: This is similar to `unlinkat(fd, path, AT_REMOVEDIR)` in POSIX. 822 823Inputs: 824 825- <a href="#path_remove_directory.fd" name="path_remove_directory.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 826 827 The working directory at which the resolution of the path starts. 828 829- <a href="#path_remove_directory.path" name="path_remove_directory.path"></a><code>const char \*<strong>path</strong></code> and <a href="#path_remove_directory.path_len" name="path_remove_directory.path_len"></a><code>size\_t <strong>path\_len</strong></code> 830 831 The path to a directory to remove. 832 833### <a href="#path_rename" name="path_rename"></a>`__wasi_path_rename()` 834 835Rename a file or directory. 836 837Note: This is similar to `renameat` in POSIX. 838 839Inputs: 840 841- <a href="#path_rename.old_fd" name="path_rename.old_fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>old\_fd</strong></code> 842 843 The working directory at which the resolution of the old path starts. 844 845- <a href="#path_rename.old_path" name="path_rename.old_path"></a><code>const char \*<strong>old\_path</strong></code> and <a href="#path_rename.old_path_len" name="path_rename.old_path_len"></a><code>size\_t <strong>old\_path\_len</strong></code> 846 847 The source path of the file or directory to rename. 848 849- <a href="#path_rename.new_fd" name="path_rename.new_fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>new\_fd</strong></code> 850 851 The working directory at which the resolution of the new path starts. 852 853- <a href="#path_rename.new_path" name="path_rename.new_path"></a><code>const char \*<strong>new\_path</strong></code> and <a href="#path_rename.new_path_len" name="path_rename.new_path_len"></a><code>size\_t <strong>new\_path\_len</strong></code> 854 855 The destination path to which to rename the file or directory. 856 857### <a href="#path_symlink" name="path_symlink"></a>`__wasi_path_symlink()` 858 859Create a symbolic link. 860 861Note: This is similar to `symlinkat` in POSIX. 862 863Inputs: 864 865- <a href="#path_symlink.old_path" name="path_symlink.old_path"></a><code>const char \*<strong>old\_path</strong></code> and <a href="#path_symlink.old_path_len" name="path_symlink.old_path_len"></a><code>size\_t <strong>old_path\_len</strong></code> 866 867 The contents of the symbolic link. 868 869- <a href="#path_symlink.fd" name="path_symlink.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 870 871 The working directory at which the resolution of the path starts. 872 873- <a href="#path_symlink.new_path" name="path_symlink.new_path"></a><code>const char \*<strong>new\_path</strong></code> and <a href="#path_symlink.new_path_len" name="path_symlink.new_path_len"></a><code>size\_t <strong>new\_path\_len</strong></code> 874 875 The destination path at which to create the symbolic link. 876 877### <a href="#path_unlink_file" name="path_unlink_file"></a>`__wasi_path_unlink_file()` 878 879Unlink a file. 880 881Return [`__WASI_EISDIR`](#errno.isdir) if the path refers to a directory. 882 883Note: This is similar to `unlinkat(fd, path, 0)` in POSIX. 884 885Inputs: 886 887- <a href="#path_unlink_file.fd" name="path_unlink_file.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 888 889 The working directory at which the resolution of the path starts. 890 891- <a href="#path_unlink_file.path" name="path_unlink_file.path"></a><code>const char \*<strong>path</strong></code> and <a href="#path_unlink_file.path_len" name="path_unlink_file.path_len"></a><code>size\_t <strong>path\_len</strong></code> 892 893 The path to a file to unlink. 894 895### <a href="#poll_oneoff" name="poll_oneoff"></a>`__wasi_poll_oneoff()` 896 897Concurrently poll for the occurrence of a set of events. 898 899Inputs: 900 901- <a href="#poll_oneoff.in" name="poll_oneoff.in"></a><code>const [\_\_wasi\_subscription\_t](#subscription) \*<strong>in</strong></code> 902 903 The events to which to subscribe. 904 905- <a href="#poll_oneoff.out" name="poll_oneoff.out"></a><code>[\_\_wasi\_event\_t](#event) \*<strong>out</strong></code> 906 907 The events that have occurred. 908 909- <a href="#poll_oneoff.nsubscriptions" name="poll_oneoff.nsubscriptions"></a><code>size\_t <strong>nsubscriptions</strong></code> 910 911 Both the number of subscriptions and events. 912 913Outputs: 914 915- <a href="#poll_oneoff.nevents" name="poll_oneoff.nevents"></a><code>size\_t <strong>nevents</strong></code> 916 917 The number of events stored. 918 919### <a href="#proc_exit" name="proc_exit"></a>`__wasi_proc_exit()` 920 921Terminate the process normally. An exit code of 0 indicates successful 922termination of the program. The meanings of other values is dependent on 923the environment. 924 925Note: This is similar to `_Exit` in POSIX. 926 927Inputs: 928 929- <a href="#proc_exit.rval" name="proc_exit.rval"></a><code>[\_\_wasi\_exitcode\_t](#exitcode) <strong>rval</strong></code> 930 931 The exit code returned by the process. 932 933Does not return. 934 935### <a href="#proc_raise" name="proc_raise"></a>`__wasi_proc_raise()` 936 937Send a signal to the process of the calling thread. 938 939Note: This is similar to `raise` in POSIX. 940 941Inputs: 942 943- <a href="#proc_raise.sig" name="proc_raise.sig"></a><code>[\_\_wasi\_signal\_t](#signal) <strong>sig</strong></code> 944 945 The signal condition to trigger. 946 947### <a href="#random_get" name="random_get"></a>`__wasi_random_get()` 948 949Write high-quality random data into a buffer. 950 951This function may execute slowly, so when large mounts of random 952data are required, it's advisable to use this function to seed a 953pseudo-random number generator, rather than to provide the 954random data directly. 955 956Inputs: 957 958- <a href="#random_get.buf" name="random_get.buf"></a><code>void \*<strong>buf</strong></code> and <a href="#random_get.buf_len" name="random_get.buf_len"></a><code>size\_t <strong>buf\_len</strong></code> 959 960 The buffer to fill with random data. 961 962### <a href="#sched_yield" name="sched_yield"></a>`__wasi_sched_yield()` 963 964Temporarily yield execution of the calling thread. 965 966Note: This is similar to `sched_yield` in POSIX. 967 968### <a href="#sock_recv" name="sock_recv"></a>`__wasi_sock_recv()` 969 970Receive a message from a socket. 971 972Note: This is similar to `recv` in POSIX, though it also supports reading 973the data into multiple buffers in the manner of `readv`. 974 975Inputs: 976 977- <a href="#sock_recv.sock" name="sock_recv.sock"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>sock</strong></code> 978 979 The socket on which to receive data. 980 981- <a href="#sock_recv.ri_data" name="sock_recv.ri_data"></a><code>const [\_\_wasi\_iovec\_t](#iovec) \*<strong>ri\_data</strong></code> and <a href="#sock_recv.ri_data_len" name="sock_recv.ri_data_len"></a><code>size\_t <strong>ri\_data\_len</strong></code> 982 983 List of scatter/gather vectors to which to store data. 984 985- <a href="#sock_recv.ri_flags" name="sock_recv.ri_flags"></a><code>[\_\_wasi\_riflags\_t](#riflags) <strong>ri\_flags</strong></code> 986 987 Message flags. 988 989Outputs: 990 991- <a href="#sock_recv.ro_datalen" name="sock_recv.ro_datalen"></a><code>size\_t <strong>ro\_datalen</strong></code> 992 993 Number of bytes stored in [`ri_data`](#sock_recv.ri_data). 994 995- <a href="#sock_recv.ro_flags" name="sock_recv.ro_flags"></a><code>[\_\_wasi\_roflags\_t](#roflags) <strong>ro\_flags</strong></code> 996 997 Message flags. 998 999### <a href="#sock_send" name="sock_send"></a>`__wasi_sock_send()` 1000 1001Send a message on a socket. 1002 1003Note: This is similar to `send` in POSIX, though it also supports writing 1004the data from multiple buffers in the manner of `writev`. 1005 1006Inputs: 1007 1008- <a href="#sock_send.sock" name="sock_send.sock"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>sock</strong></code> 1009 1010 The socket on which to send data. 1011 1012- <a href="#sock_send.si_data" name="sock_send.si_data"></a><code>const [\_\_wasi\_ciovec\_t](#ciovec) \*<strong>si\_data</strong></code> and <a href="#sock_send.si_data_len" name="sock_send.si_data_len"></a><code>size\_t <strong>si\_data\_len</strong></code> 1013 1014 List of scatter/gather vectors to which to retrieve data 1015 1016- <a href="#sock_send.si_flags" name="sock_send.si_flags"></a><code>[\_\_wasi\_siflags\_t](#siflags) <strong>si\_flags</strong></code> 1017 1018 Message flags. 1019 1020Outputs: 1021 1022- <a href="#sock_send.so_datalen" name="sock_send.so_datalen"></a><code>size\_t <strong>so\_datalen</strong></code> 1023 1024 Number of bytes transmitted. 1025 1026### <a href="#sock_shutdown" name="sock_shutdown"></a>`__wasi_sock_shutdown()` 1027 1028Shut down socket send and receive channels. 1029 1030Note: This is similar to `shutdown` in POSIX. 1031 1032Inputs: 1033 1034- <a href="#sock_shutdown.sock" name="sock_shutdown.sock"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>sock</strong></code> 1035 1036 The socket on which to shutdown channels. 1037 1038- <a href="#sock_shutdown.how" name="sock_shutdown.how"></a><code>[\_\_wasi\_sdflags\_t](#sdflags) <strong>how</strong></code> 1039 1040 Which channels on the socket to shut down. 1041 1042## Types 1043 1044### <a href="#advice" name="advice"></a>`__wasi_advice_t` (`uint8_t`) 1045 1046File or memory access pattern advisory information. 1047 1048Used by [`__wasi_fd_advise()`](#fd_advise). 1049 1050Possible values: 1051 1052- <a href="#advice.dontneed" name="advice.dontneed"></a>**`__WASI_ADVICE_DONTNEED`** 1053 1054 The application expects that it will not access the 1055 specified data in the near future. 1056 1057- <a href="#advice.noreuse" name="advice.noreuse"></a>**`__WASI_ADVICE_NOREUSE`** 1058 1059 The application expects to access the specified data 1060 once and then not reuse it thereafter. 1061 1062- <a href="#advice.normal" name="advice.normal"></a>**`__WASI_ADVICE_NORMAL`** 1063 1064 The application has no advice to give on its behavior 1065 with respect to the specified data. 1066 1067- <a href="#advice.random" name="advice.random"></a>**`__WASI_ADVICE_RANDOM`** 1068 1069 The application expects to access the specified data 1070 in a random order. 1071 1072- <a href="#advice.sequential" name="advice.sequential"></a>**`__WASI_ADVICE_SEQUENTIAL`** 1073 1074 The application expects to access the specified data 1075 sequentially from lower offsets to higher offsets. 1076 1077- <a href="#advice.willneed" name="advice.willneed"></a>**`__WASI_ADVICE_WILLNEED`** 1078 1079 The application expects to access the specified data 1080 in the near future. 1081 1082### <a href="#ciovec" name="ciovec"></a>`__wasi_ciovec_t` (`struct`) 1083 1084A region of memory for scatter/gather writes. 1085 1086Used by [`__wasi_fd_pwrite()`](#fd_pwrite), [`__wasi_fd_write()`](#fd_write), and [`__wasi_sock_send()`](#sock_send). 1087 1088Members: 1089 1090- <a href="#ciovec.buf" name="ciovec.buf"></a><code>const void \*<strong>buf</strong></code> and <a href="#ciovec.buf_len" name="ciovec.buf_len"></a><code>size\_t <strong>buf\_len</strong></code> 1091 1092 The address and length of the buffer to be written. 1093 1094### <a href="#clockid" name="clockid"></a>`__wasi_clockid_t` (`uint32_t`) 1095 1096Identifiers for clocks. 1097 1098Used by [`__wasi_subscription_t`](#subscription), [`__wasi_clock_res_get()`](#clock_res_get), and [`__wasi_clock_time_get()`](#clock_time_get). 1099 1100Possible values: 1101 1102- <a href="#clockid.monotonic" name="clockid.monotonic"></a>**`__WASI_CLOCK_MONOTONIC`** 1103 1104 The store-wide monotonic clock, which is defined as a 1105 clock measuring real time, whose value cannot be 1106 adjusted and which cannot have negative clock jumps. 1107 1108 The epoch of this clock is undefined. The absolute 1109 time value of this clock therefore has no meaning. 1110 1111- <a href="#clockid.process_cputime_id" name="clockid.process_cputime_id"></a>**`__WASI_CLOCK_PROCESS_CPUTIME_ID`** 1112 1113 The CPU-time clock associated with the current 1114 process. 1115 1116- <a href="#clockid.realtime" name="clockid.realtime"></a>**`__WASI_CLOCK_REALTIME`** 1117 1118 The clock measuring real time. Time value 1119 zero corresponds with 1970-01-01T00:00:00Z. 1120 1121- <a href="#clockid.thread_cputime_id" name="clockid.thread_cputime_id"></a>**`__WASI_CLOCK_THREAD_CPUTIME_ID`** 1122 1123 The CPU-time clock associated with the current thread. 1124 1125### <a href="#device" name="device"></a>`__wasi_device_t` (`uint64_t`) 1126 1127Identifier for a device containing a file system. Can be used 1128in combination with [`__wasi_inode_t`](#inode) to uniquely identify a file or 1129directory in the filesystem. 1130 1131Used by [`__wasi_filestat_t`](#filestat). 1132 1133### <a href="#dircookie" name="dircookie"></a>`__wasi_dircookie_t` (`uint64_t`) 1134 1135A reference to the offset of a directory entry. 1136 1137Used by [`__wasi_dirent_t`](#dirent) and [`__wasi_fd_readdir()`](#fd_readdir). 1138 1139Special values: 1140 1141- <a href="#dircookie.start" name="dircookie.start"></a>**`__WASI_DIRCOOKIE_START`** 1142 1143 Permanent reference to the first directory entry 1144 within a directory. 1145 1146### <a href="#dirent" name="dirent"></a>`__wasi_dirent_t` (`struct`) 1147 1148A directory entry. 1149 1150Members: 1151 1152- <a href="#dirent.d_next" name="dirent.d_next"></a><code>[\_\_wasi\_dircookie\_t](#dircookie) <strong>d\_next</strong></code> 1153 1154 The offset of the next directory entry stored in this 1155 directory. 1156 1157- <a href="#dirent.d_ino" name="dirent.d_ino"></a><code>[\_\_wasi\_inode\_t](#inode) <strong>d\_ino</strong></code> 1158 1159 The serial number of the file referred to by this 1160 directory entry. 1161 1162- <a href="#dirent.d_namlen" name="dirent.d_namlen"></a><code>uint32\_t <strong>d\_namlen</strong></code> 1163 1164 The length of the name of the directory entry. 1165 1166- <a href="#dirent.d_type" name="dirent.d_type"></a><code>[\_\_wasi\_filetype\_t](#filetype) <strong>d\_type</strong></code> 1167 1168 The type of the file referred to by this directory 1169 entry. 1170 1171### <a href="#errno" name="errno"></a>`__wasi_errno_t` (`uint16_t`) 1172 1173Error codes returned by functions. 1174 1175Not all of these error codes are returned by the functions 1176provided by this API; some are used in higher-level library layers, 1177and others are provided merely for alignment with POSIX. 1178 1179Used by [`__wasi_event_t`](#event). 1180 1181Possible values: 1182 1183- <a href="#errno.success" name="errno.success"></a>**`__WASI_ESUCCESS`** 1184 1185 No error occurred. System call completed successfully. 1186 1187- <a href="#errno.2big" name="errno.2big"></a>**`__WASI_E2BIG`** 1188 1189 Argument list too long. 1190 1191- <a href="#errno.acces" name="errno.acces"></a>**`__WASI_EACCES`** 1192 1193 Permission denied. 1194 1195- <a href="#errno.addrinuse" name="errno.addrinuse"></a>**`__WASI_EADDRINUSE`** 1196 1197 Address in use. 1198 1199- <a href="#errno.addrnotavail" name="errno.addrnotavail"></a>**`__WASI_EADDRNOTAVAIL`** 1200 1201 Address not available. 1202 1203- <a href="#errno.afnosupport" name="errno.afnosupport"></a>**`__WASI_EAFNOSUPPORT`** 1204 1205 Address family not supported. 1206 1207- <a href="#errno.again" name="errno.again"></a>**`__WASI_EAGAIN`** 1208 1209 Resource unavailable, or operation would block. 1210 1211- <a href="#errno.already" name="errno.already"></a>**`__WASI_EALREADY`** 1212 1213 Connection already in progress. 1214 1215- <a href="#errno.badf" name="errno.badf"></a>**`__WASI_EBADF`** 1216 1217 Bad file descriptor. 1218 1219- <a href="#errno.badmsg" name="errno.badmsg"></a>**`__WASI_EBADMSG`** 1220 1221 Bad message. 1222 1223- <a href="#errno.busy" name="errno.busy"></a>**`__WASI_EBUSY`** 1224 1225 Device or resource busy. 1226 1227- <a href="#errno.canceled" name="errno.canceled"></a>**`__WASI_ECANCELED`** 1228 1229 Operation canceled. 1230 1231- <a href="#errno.child" name="errno.child"></a>**`__WASI_ECHILD`** 1232 1233 No child processes. 1234 1235- <a href="#errno.connaborted" name="errno.connaborted"></a>**`__WASI_ECONNABORTED`** 1236 1237 Connection aborted. 1238 1239- <a href="#errno.connrefused" name="errno.connrefused"></a>**`__WASI_ECONNREFUSED`** 1240 1241 Connection refused. 1242 1243- <a href="#errno.connreset" name="errno.connreset"></a>**`__WASI_ECONNRESET`** 1244 1245 Connection reset. 1246 1247- <a href="#errno.deadlk" name="errno.deadlk"></a>**`__WASI_EDEADLK`** 1248 1249 Resource deadlock would occur. 1250 1251- <a href="#errno.destaddrreq" name="errno.destaddrreq"></a>**`__WASI_EDESTADDRREQ`** 1252 1253 Destination address required. 1254 1255- <a href="#errno.dom" name="errno.dom"></a>**`__WASI_EDOM`** 1256 1257 Mathematics argument out of domain of function. 1258 1259- <a href="#errno.dquot" name="errno.dquot"></a>**`__WASI_EDQUOT`** 1260 1261 Reserved. 1262 1263- <a href="#errno.exist" name="errno.exist"></a>**`__WASI_EEXIST`** 1264 1265 File exists. 1266 1267- <a href="#errno.fault" name="errno.fault"></a>**`__WASI_EFAULT`** 1268 1269 Bad address. 1270 1271- <a href="#errno.fbig" name="errno.fbig"></a>**`__WASI_EFBIG`** 1272 1273 File too large. 1274 1275- <a href="#errno.hostunreach" name="errno.hostunreach"></a>**`__WASI_EHOSTUNREACH`** 1276 1277 Host is unreachable. 1278 1279- <a href="#errno.idrm" name="errno.idrm"></a>**`__WASI_EIDRM`** 1280 1281 Identifier removed. 1282 1283- <a href="#errno.ilseq" name="errno.ilseq"></a>**`__WASI_EILSEQ`** 1284 1285 Illegal byte sequence. 1286 1287- <a href="#errno.inprogress" name="errno.inprogress"></a>**`__WASI_EINPROGRESS`** 1288 1289 Operation in progress. 1290 1291- <a href="#errno.intr" name="errno.intr"></a>**`__WASI_EINTR`** 1292 1293 Interrupted function. 1294 1295- <a href="#errno.inval" name="errno.inval"></a>**`__WASI_EINVAL`** 1296 1297 Invalid argument. 1298 1299- <a href="#errno.io" name="errno.io"></a>**`__WASI_EIO`** 1300 1301 I/O error. 1302 1303- <a href="#errno.isconn" name="errno.isconn"></a>**`__WASI_EISCONN`** 1304 1305 Socket is connected. 1306 1307- <a href="#errno.isdir" name="errno.isdir"></a>**`__WASI_EISDIR`** 1308 1309 Is a directory. 1310 1311- <a href="#errno.loop" name="errno.loop"></a>**`__WASI_ELOOP`** 1312 1313 Too many levels of symbolic links. 1314 1315- <a href="#errno.mfile" name="errno.mfile"></a>**`__WASI_EMFILE`** 1316 1317 File descriptor value too large. 1318 1319- <a href="#errno.mlink" name="errno.mlink"></a>**`__WASI_EMLINK`** 1320 1321 Too many links. 1322 1323- <a href="#errno.msgsize" name="errno.msgsize"></a>**`__WASI_EMSGSIZE`** 1324 1325 Message too large. 1326 1327- <a href="#errno.multihop" name="errno.multihop"></a>**`__WASI_EMULTIHOP`** 1328 1329 Reserved. 1330 1331- <a href="#errno.nametoolong" name="errno.nametoolong"></a>**`__WASI_ENAMETOOLONG`** 1332 1333 Filename too long. 1334 1335- <a href="#errno.netdown" name="errno.netdown"></a>**`__WASI_ENETDOWN`** 1336 1337 Network is down. 1338 1339- <a href="#errno.netreset" name="errno.netreset"></a>**`__WASI_ENETRESET`** 1340 1341 Connection aborted by network. 1342 1343- <a href="#errno.netunreach" name="errno.netunreach"></a>**`__WASI_ENETUNREACH`** 1344 1345 Network unreachable. 1346 1347- <a href="#errno.nfile" name="errno.nfile"></a>**`__WASI_ENFILE`** 1348 1349 Too many files open in system. 1350 1351- <a href="#errno.nobufs" name="errno.nobufs"></a>**`__WASI_ENOBUFS`** 1352 1353 No buffer space available. 1354 1355- <a href="#errno.nodev" name="errno.nodev"></a>**`__WASI_ENODEV`** 1356 1357 No such device. 1358 1359- <a href="#errno.noent" name="errno.noent"></a>**`__WASI_ENOENT`** 1360 1361 No such file or directory. 1362 1363- <a href="#errno.noexec" name="errno.noexec"></a>**`__WASI_ENOEXEC`** 1364 1365 Executable file format error. 1366 1367- <a href="#errno.nolck" name="errno.nolck"></a>**`__WASI_ENOLCK`** 1368 1369 No locks available. 1370 1371- <a href="#errno.nolink" name="errno.nolink"></a>**`__WASI_ENOLINK`** 1372 1373 Reserved. 1374 1375- <a href="#errno.nomem" name="errno.nomem"></a>**`__WASI_ENOMEM`** 1376 1377 Not enough space. 1378 1379- <a href="#errno.nomsg" name="errno.nomsg"></a>**`__WASI_ENOMSG`** 1380 1381 No message of the desired type. 1382 1383- <a href="#errno.noprotoopt" name="errno.noprotoopt"></a>**`__WASI_ENOPROTOOPT`** 1384 1385 Protocol not available. 1386 1387- <a href="#errno.nospc" name="errno.nospc"></a>**`__WASI_ENOSPC`** 1388 1389 No space left on device. 1390 1391- <a href="#errno.nosys" name="errno.nosys"></a>**`__WASI_ENOSYS`** 1392 1393 Function not supported. 1394 1395- <a href="#errno.notconn" name="errno.notconn"></a>**`__WASI_ENOTCONN`** 1396 1397 The socket is not connected. 1398 1399- <a href="#errno.notdir" name="errno.notdir"></a>**`__WASI_ENOTDIR`** 1400 1401 Not a directory or a symbolic link to a directory. 1402 1403- <a href="#errno.notempty" name="errno.notempty"></a>**`__WASI_ENOTEMPTY`** 1404 1405 Directory not empty. 1406 1407- <a href="#errno.notrecoverable" name="errno.notrecoverable"></a>**`__WASI_ENOTRECOVERABLE`** 1408 1409 State not recoverable. 1410 1411- <a href="#errno.notsock" name="errno.notsock"></a>**`__WASI_ENOTSOCK`** 1412 1413 Not a socket. 1414 1415- <a href="#errno.notsup" name="errno.notsup"></a>**`__WASI_ENOTSUP`** 1416 1417 Not supported, or operation not supported on socket. 1418 1419- <a href="#errno.notty" name="errno.notty"></a>**`__WASI_ENOTTY`** 1420 1421 Inappropriate I/O control operation. 1422 1423- <a href="#errno.nxio" name="errno.nxio"></a>**`__WASI_ENXIO`** 1424 1425 No such device or address. 1426 1427- <a href="#errno.overflow" name="errno.overflow"></a>**`__WASI_EOVERFLOW`** 1428 1429 Value too large to be stored in data type. 1430 1431- <a href="#errno.ownerdead" name="errno.ownerdead"></a>**`__WASI_EOWNERDEAD`** 1432 1433 Previous owner died. 1434 1435- <a href="#errno.perm" name="errno.perm"></a>**`__WASI_EPERM`** 1436 1437 Operation not permitted. 1438 1439- <a href="#errno.pipe" name="errno.pipe"></a>**`__WASI_EPIPE`** 1440 1441 Broken pipe. 1442 1443- <a href="#errno.proto" name="errno.proto"></a>**`__WASI_EPROTO`** 1444 1445 Protocol error. 1446 1447- <a href="#errno.protonosupport" name="errno.protonosupport"></a>**`__WASI_EPROTONOSUPPORT`** 1448 1449 Protocol not supported. 1450 1451- <a href="#errno.prototype" name="errno.prototype"></a>**`__WASI_EPROTOTYPE`** 1452 1453 Protocol wrong type for socket. 1454 1455- <a href="#errno.range" name="errno.range"></a>**`__WASI_ERANGE`** 1456 1457 Result too large. 1458 1459- <a href="#errno.rofs" name="errno.rofs"></a>**`__WASI_EROFS`** 1460 1461 Read-only file system. 1462 1463- <a href="#errno.spipe" name="errno.spipe"></a>**`__WASI_ESPIPE`** 1464 1465 Invalid seek. 1466 1467- <a href="#errno.srch" name="errno.srch"></a>**`__WASI_ESRCH`** 1468 1469 No such process. 1470 1471- <a href="#errno.stale" name="errno.stale"></a>**`__WASI_ESTALE`** 1472 1473 Reserved. 1474 1475- <a href="#errno.timedout" name="errno.timedout"></a>**`__WASI_ETIMEDOUT`** 1476 1477 Connection timed out. 1478 1479- <a href="#errno.txtbsy" name="errno.txtbsy"></a>**`__WASI_ETXTBSY`** 1480 1481 Text file busy. 1482 1483- <a href="#errno.xdev" name="errno.xdev"></a>**`__WASI_EXDEV`** 1484 1485 Cross-device link. 1486 1487- <a href="#errno.notcapable" name="errno.notcapable"></a>**`__WASI_ENOTCAPABLE`** 1488 1489 Extension: Capabilities insufficient. 1490 1491### <a href="#event" name="event"></a>`__wasi_event_t` (`struct`) 1492 1493An event that occurred. 1494 1495Used by [`__wasi_poll_oneoff()`](#poll_oneoff). 1496 1497Members: 1498 1499- <a href="#event.userdata" name="event.userdata"></a><code>[\_\_wasi\_userdata\_t](#userdata) <strong>userdata</strong></code> 1500 1501 User-provided value that got attached to 1502 [`__wasi_subscription_t::userdata`](#subscription.userdata). 1503 1504- <a href="#event.error" name="event.error"></a><code>[\_\_wasi\_errno\_t](#errno) <strong>error</strong></code> 1505 1506 If non-zero, an error that occurred while processing 1507 the subscription request. 1508 1509- <a href="#event.type" name="event.type"></a><code>[\_\_wasi\_eventtype\_t](#eventtype) <strong>type</strong></code> 1510 1511 The type of the event that occurred. 1512 1513- When `type` is [`__WASI_EVENTTYPE_FD_READ`](#eventtype.fd_read) or [`__WASI_EVENTTYPE_FD_WRITE`](#eventtype.fd_write): 1514 1515 - <a href="#event.u.fd_readwrite" name="event.u.fd_readwrite"></a>**`u.fd_readwrite`** 1516 1517 - <a href="#event.u.fd_readwrite.nbytes" name="event.u.fd_readwrite.nbytes"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>nbytes</strong></code> 1518 1519 The number of bytes available for reading or writing. 1520 1521 - <a href="#event.u.fd_readwrite.flags" name="event.u.fd_readwrite.flags"></a><code>[\_\_wasi\_eventrwflags\_t](#eventrwflags) <strong>flags</strong></code> 1522 1523 The state of the file descriptor. 1524 1525### <a href="#eventrwflags" name="eventrwflags"></a>`__wasi_eventrwflags_t` (`uint16_t` bitfield) 1526 1527The state of the file descriptor subscribed to with 1528[`__WASI_EVENTTYPE_FD_READ`](#eventtype.fd_read) or [`__WASI_EVENTTYPE_FD_WRITE`](#eventtype.fd_write). 1529 1530Used by [`__wasi_event_t`](#event). 1531 1532Possible values: 1533 1534- <a href="#eventrwflags.hangup" name="eventrwflags.hangup"></a>**`__WASI_EVENT_FD_READWRITE_HANGUP`** 1535 1536 The peer of this socket has closed or disconnected. 1537 1538### <a href="#eventtype" name="eventtype"></a>`__wasi_eventtype_t` (`uint8_t`) 1539 1540Type of a subscription to an event or its occurrence. 1541 1542Used by [`__wasi_event_t`](#event) and [`__wasi_subscription_t`](#subscription). 1543 1544Possible values: 1545 1546- <a href="#eventtype.u.clock" name="eventtype.u.clock"></a>**`__WASI_EVENTTYPE_CLOCK`** 1547 1548 The time value of clock [`__wasi_subscription_t::u.clock.clock_id`](#subscription.u.clock.clock_id) 1549 has reached timestamp [`__wasi_subscription_t::u.clock.timeout`](#subscription.u.clock.timeout). 1550 1551- <a href="#eventtype.fd_read" name="eventtype.fd_read"></a>**`__WASI_EVENTTYPE_FD_READ`** 1552 1553 File descriptor [`__wasi_subscription_t::u.fd_readwrite.fd`](#subscription.u.fd_readwrite.fd) has 1554 data available for reading. This event always triggers 1555 for regular files. 1556 1557- <a href="#eventtype.fd_write" name="eventtype.fd_write"></a>**`__WASI_EVENTTYPE_FD_WRITE`** 1558 1559 File descriptor [`__wasi_subscription_t::u.fd_readwrite.fd`](#subscription.u.fd_readwrite.fd) has 1560 capacity available for writing. This event always 1561 triggers for regular files. 1562 1563### <a href="#exitcode" name="exitcode"></a>`__wasi_exitcode_t` (`uint32_t`) 1564 1565Exit code generated by a process when exiting. 1566 1567Used by [`__wasi_proc_exit()`](#proc_exit). 1568 1569### <a href="#fd" name="fd"></a>`__wasi_fd_t` (`uint32_t`) 1570 1571A file descriptor number. 1572 1573Used by many functions in this API. 1574 1575As in POSIX, three file descriptor numbers are provided to instances 1576on startup -- 0, 1, and 2, (a.k.a. `STDIN_FILENO`, `STDOUT_FILENO`, 1577and `STDERR_FILENO`). 1578 1579Other than these, WASI implementations are not required to allocate 1580new file descriptors in ascending order. 1581 1582### <a href="#fdflags" name="fdflags"></a>`__wasi_fdflags_t` (`uint16_t` bitfield) 1583 1584File descriptor flags. 1585 1586Used by [`__wasi_fdstat_t`](#fdstat), [`__wasi_fd_fdstat_set_flags()`](#fd_fdstat_set_flags), and [`__wasi_path_open()`](#path_open). 1587 1588Possible values: 1589 1590- <a href="#fdflags.append" name="fdflags.append"></a>**`__WASI_FDFLAG_APPEND`** 1591 1592 Append mode: Data written to the file is always 1593 appended to the file's end. 1594 1595- <a href="#fdflags.dsync" name="fdflags.dsync"></a>**`__WASI_FDFLAG_DSYNC`** 1596 1597 Write according to synchronized I/O data integrity 1598 completion. Only the data stored in the file is 1599 synchronized. 1600 1601- <a href="#fdflags.nonblock" name="fdflags.nonblock"></a>**`__WASI_FDFLAG_NONBLOCK`** 1602 1603 Non-blocking mode. 1604 1605- <a href="#fdflags.rsync" name="fdflags.rsync"></a>**`__WASI_FDFLAG_RSYNC`** 1606 1607 Synchronized read I/O operations. 1608 1609- <a href="#fdflags.sync" name="fdflags.sync"></a>**`__WASI_FDFLAG_SYNC`** 1610 1611 Write according to synchronized I/O file integrity completion. 1612 In addition to synchronizing the data stored in the file, the 1613 implementation may also synchronously update the file's metadata. 1614 1615### <a href="#fdstat" name="fdstat"></a>`__wasi_fdstat_t` (`struct`) 1616 1617File descriptor attributes. 1618 1619Used by [`__wasi_fd_fdstat_get()`](#fd_fdstat_get). 1620 1621Members: 1622 1623- <a href="#fdstat.fs_filetype" name="fdstat.fs_filetype"></a><code>[\_\_wasi\_filetype\_t](#filetype) <strong>fs\_filetype</strong></code> 1624 1625 File type. 1626 1627- <a href="#fdstat.fs_flags" name="fdstat.fs_flags"></a><code>[\_\_wasi\_fdflags\_t](#fdflags) <strong>fs\_flags</strong></code> 1628 1629 File descriptor flags. 1630 1631- <a href="#fdstat.fs_rights_base" name="fdstat.fs_rights_base"></a><code>[\_\_wasi\_rights\_t](#rights) <strong>fs\_rights\_base</strong></code> 1632 1633 Rights that apply to this file descriptor. 1634 1635- <a href="#fdstat.fs_rights_inheriting" name="fdstat.fs_rights_inheriting"></a><code>[\_\_wasi\_rights\_t](#rights) <strong>fs\_rights\_inheriting</strong></code> 1636 1637 Maximum set of rights that may be installed on new 1638 file descriptors that are created through this file 1639 descriptor, e.g., through [`__wasi_path_open()`](#path_open). 1640 1641### <a href="#filedelta" name="filedelta"></a>`__wasi_filedelta_t` (`int64_t`) 1642 1643Relative offset within a file. 1644 1645Used by [`__wasi_fd_seek()`](#fd_seek). 1646 1647### <a href="#filesize" name="filesize"></a>`__wasi_filesize_t` (`uint64_t`) 1648 1649Non-negative file size or length of a region within a file. 1650 1651Used by [`__wasi_event_t`](#event), [`__wasi_filestat_t`](#filestat), [`__wasi_fd_pread()`](#fd_pread), [`__wasi_fd_pwrite()`](#fd_pwrite), [`__wasi_fd_seek()`](#fd_seek), [`__wasi_path_tell()`](#path_tell), [`__wasi_fd_advise()`](#fd_advise), [`__wasi_fd_allocate()`](#fd_allocate), and [`__wasi_fd_filestat_set_size()`](#fd_filestat_set_size). 1652 1653### <a href="#filestat" name="filestat"></a>`__wasi_filestat_t` (`struct`) 1654 1655File attributes. 1656 1657Used by [`__wasi_fd_filestat_get()`](#fd_filestat_get) and [`__wasi_path_filestat_get()`](#path_filestat_get). 1658 1659Members: 1660 1661- <a href="#filestat.st_dev" name="filestat.st_dev"></a><code>[\_\_wasi\_device\_t](#device) <strong>st\_dev</strong></code> 1662 1663 Device ID of device containing the file. 1664 1665- <a href="#filestat.st_ino" name="filestat.st_ino"></a><code>[\_\_wasi\_inode\_t](#inode) <strong>st\_ino</strong></code> 1666 1667 File serial number. 1668 1669- <a href="#filestat.st_filetype" name="filestat.st_filetype"></a><code>[\_\_wasi\_filetype\_t](#filetype) <strong>st\_filetype</strong></code> 1670 1671 File type. 1672 1673- <a href="#filestat.st_nlink" name="filestat.st_nlink"></a><code>[\_\_wasi\_linkcount\_t](#linkcount) <strong>st\_nlink</strong></code> 1674 1675 Number of hard links to the file. 1676 1677- <a href="#filestat.st_size" name="filestat.st_size"></a><code>[\_\_wasi\_filesize\_t](#filesize) <strong>st\_size</strong></code> 1678 1679 For regular files, the file size in bytes. For 1680 symbolic links, the length in bytes of the pathname 1681 contained in the symbolic link. 1682 1683- <a href="#filestat.st_atim" name="filestat.st_atim"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>st\_atim</strong></code> 1684 1685 Last data access timestamp. 1686 1687- <a href="#filestat.st_mtim" name="filestat.st_mtim"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>st\_mtim</strong></code> 1688 1689 Last data modification timestamp. 1690 1691- <a href="#filestat.st_ctim" name="filestat.st_ctim"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>st\_ctim</strong></code> 1692 1693 Last file status change timestamp. 1694 1695### <a href="#filetype" name="filetype"></a>`__wasi_filetype_t` (`uint8_t`) 1696 1697The type of a file descriptor or file. 1698 1699Used by [`__wasi_dirent_t`](#dirent), [`__wasi_fdstat_t`](#fdstat), and [`__wasi_filestat_t`](#filestat). 1700 1701Possible values: 1702 1703- <a href="#filetype.unknown" name="filetype.unknown"></a>**`__WASI_FILETYPE_UNKNOWN`** 1704 1705 The type of the file descriptor or file is unknown or 1706 is different from any of the other types specified. 1707 1708- <a href="#filetype.block_device" name="filetype.block_device"></a>**`__WASI_FILETYPE_BLOCK_DEVICE`** 1709 1710 The file descriptor or file refers to a block device 1711 inode. 1712 1713- <a href="#filetype.character_device" name="filetype.character_device"></a>**`__WASI_FILETYPE_CHARACTER_DEVICE`** 1714 1715 The file descriptor or file refers to a character 1716 device inode. 1717 1718- <a href="#filetype.directory" name="filetype.directory"></a>**`__WASI_FILETYPE_DIRECTORY`** 1719 1720 The file descriptor or file refers to a directory 1721 inode. 1722 1723- <a href="#filetype.regular_file" name="filetype.regular_file"></a>**`__WASI_FILETYPE_REGULAR_FILE`** 1724 1725 The file descriptor or file refers to a regular file 1726 inode. 1727 1728- <a href="#filetype.socket_dgram" name="filetype.socket_dgram"></a>**`__WASI_FILETYPE_SOCKET_DGRAM`** 1729 1730 The file descriptor or file refers to a datagram 1731 socket. 1732 1733- <a href="#filetype.socket_stream" name="filetype.socket_stream"></a>**`__WASI_FILETYPE_SOCKET_STREAM`** 1734 1735 The file descriptor or file refers to a byte-stream 1736 socket. 1737 1738- <a href="#filetype.symbolic_link" name="filetype.symbolic_link"></a>**`__WASI_FILETYPE_SYMBOLIC_LINK`** 1739 1740 The file refers to a symbolic link inode. 1741 1742### <a href="#fstflags" name="fstflags"></a>`__wasi_fstflags_t` (`uint16_t` bitfield) 1743 1744Which file time attributes to adjust. 1745 1746Used by [`__wasi_fd_filestat_set_times()`](#fd_filestat_set_times) and [`__wasi_path_filestat_set_times()`](#path_filestat_set_times). 1747 1748Possible values: 1749 1750- <a href="#fstflags.atim" name="fstflags.atim"></a>**`__WASI_FILESTAT_SET_ATIM`** 1751 1752 Adjust the last data access timestamp to the value 1753 stored in [`__wasi_filestat_t::st_atim`](#filestat.st_atim). 1754 1755- <a href="#fstflags.atim_now" name="fstflags.atim_now"></a>**`__WASI_FILESTAT_SET_ATIM_NOW`** 1756 1757 Adjust the last data access timestamp to the time 1758 of clock [`__WASI_CLOCK_REALTIME`](#clockid.realtime). 1759 1760- <a href="#fstflags.mtim" name="fstflags.mtim"></a>**`__WASI_FILESTAT_SET_MTIM`** 1761 1762 Adjust the last data modification timestamp to the 1763 value stored in [`__wasi_filestat_t::st_mtim`](#filestat.st_mtim). 1764 1765- <a href="#fstflags.mtim_now" name="fstflags.mtim_now"></a>**`__WASI_FILESTAT_SET_MTIM_NOW`** 1766 1767 Adjust the last data modification timestamp to the 1768 time of clock [`__WASI_CLOCK_REALTIME`](#clockid.realtime). 1769 1770### <a href="#inode" name="inode"></a>`__wasi_inode_t` (`uint64_t`) 1771 1772File serial number that is unique within its file system. 1773 1774Used by [`__wasi_dirent_t`](#dirent) and [`__wasi_filestat_t`](#filestat). 1775 1776### <a href="#iovec" name="iovec"></a>`__wasi_iovec_t` (`struct`) 1777 1778A region of memory for scatter/gather reads. 1779 1780Used by [`__wasi_fd_pread()`](#fd_pread), [`__wasi_fd_read()`](#fd_read), and [`__wasi_sock_recv()`](#sock_recv). 1781 1782Members: 1783 1784- <a href="#iovec.buf" name="iovec.buf"></a><code>void \*<strong>buf</strong></code> and <a href="#iovec.buf_len" name="iovec.buf_len"></a><code>size\_t <strong>buf\_len</strong></code> 1785 1786 The address and length of the buffer to be filled. 1787 1788### <a href="#linkcount" name="linkcount"></a>`__wasi_linkcount_t` (`uint32_t`) 1789 1790Number of hard links to an inode. 1791 1792Used by [`__wasi_filestat_t`](#filestat). 1793 1794### <a href="#lookupflags" name="lookupflags"></a>`__wasi_lookupflags_t` (`uint32_t` bitfield) 1795 1796Flags determining the method of how paths are resolved. 1797 1798Used by [`__wasi_path_filestat_get()`](#path_filestat_get), [`__wasi_path_filestat_set_times()`](#path_filestat_set_times), [`__wasi_path_link()`](#path_link), and [`__wasi_path_open()`](#path_open). 1799 1800Possible values: 1801 1802- <a href="#lookupflags.symlink_follow" name="lookupflags.symlink_follow"></a>**`__WASI_LOOKUP_SYMLINK_FOLLOW`** 1803 1804 As long as the resolved path corresponds to a symbolic 1805 link, it is expanded. 1806 1807### <a href="#oflags" name="oflags"></a>`__wasi_oflags_t` (`uint16_t` bitfield) 1808 1809Open flags used by [`__wasi_path_open()`](#path_open). 1810 1811Used by [`__wasi_path_open()`](#path_open). 1812 1813Possible values: 1814 1815- <a href="#oflags.creat" name="oflags.creat"></a>**`__WASI_O_CREAT`** 1816 1817 Create file if it does not exist. 1818 1819- <a href="#oflags.directory" name="oflags.directory"></a>**`__WASI_O_DIRECTORY`** 1820 1821 Fail if not a directory. 1822 1823- <a href="#oflags.excl" name="oflags.excl"></a>**`__WASI_O_EXCL`** 1824 1825 Fail if file already exists. 1826 1827- <a href="#oflags.trunc" name="oflags.trunc"></a>**`__WASI_O_TRUNC`** 1828 1829 Truncate file to size 0. 1830 1831### <a href="#riflags" name="riflags"></a>`__wasi_riflags_t` (`uint16_t` bitfield) 1832 1833Flags provided to [`__wasi_sock_recv()`](#sock_recv). 1834 1835Used by [`__wasi_sock_recv()`](#sock_recv). 1836 1837Possible values: 1838 1839- <a href="#riflags.peek" name="riflags.peek"></a>**`__WASI_SOCK_RECV_PEEK`** 1840 1841 Returns the message without removing it from the 1842 socket's receive queue. 1843 1844- <a href="#riflags.waitall" name="riflags.waitall"></a>**`__WASI_SOCK_RECV_WAITALL`** 1845 1846 On byte-stream sockets, block until the full amount 1847 of data can be returned. 1848 1849### <a href="#rights" name="rights"></a>`__wasi_rights_t` (`uint64_t` bitfield) 1850 1851File descriptor rights, determining which actions may be 1852performed. 1853 1854Used by [`__wasi_fdstat_t`](#fdstat), [`__wasi_fd_fdstat_set_rights()`](#fd_fdstat_set_rights), and [`__wasi_path_open()`](#path_open). 1855 1856Possible values: 1857 1858- <a href="#rights.fd_datasync" name="rights.fd_datasync"></a>**`__WASI_RIGHT_FD_DATASYNC`** 1859 1860 The right to invoke [`__wasi_fd_datasync()`](#fd_datasync). 1861 1862 If [`__WASI_RIGHT_PATH_OPEN`](#rights.path_open) is set, includes the right to 1863 invoke [`__wasi_path_open()`](#path_open) with [`__WASI_FDFLAG_DSYNC`](#fdflags.dsync). 1864 1865- <a href="#rights.fd_read" name="rights.fd_read"></a>**`__WASI_RIGHT_FD_READ`** 1866 1867 The right to invoke [`__wasi_fd_read()`](#fd_read) and [`__wasi_sock_recv()`](#sock_recv). 1868 1869 If [`__WASI_RIGHT_FD_SEEK`](#rights.fd_seek) is set, includes the right to invoke 1870 [`__wasi_fd_pread()`](#fd_pread). 1871 1872- <a href="#rights.fd_seek" name="rights.fd_seek"></a>**`__WASI_RIGHT_FD_SEEK`** 1873 1874 The right to invoke [`__wasi_fd_seek()`](#fd_seek). This flag implies 1875 [`__WASI_RIGHT_FD_TELL`](#rights.fd_tell). 1876 1877- <a href="#rights.fd_fdstat_set_flags" name="rights.fd_fdstat_set_flags"></a>**`__WASI_RIGHT_FD_FDSTAT_SET_FLAGS`** 1878 1879 The right to invoke [`__wasi_fd_fdstat_set_flags()`](#fd_fdstat_set_flags). 1880 1881- <a href="#rights.fd_sync" name="rights.fd_sync"></a>**`__WASI_RIGHT_FD_SYNC`** 1882 1883 The right to invoke [`__wasi_fd_sync()`](#fd_sync). 1884 1885 If [`__WASI_RIGHT_PATH_OPEN`](#rights.path_open) is set, includes the right to 1886 invoke [`__wasi_path_open()`](#path_open) with [`__WASI_FDFLAG_RSYNC`](#fdflags.rsync) and 1887 [`__WASI_FDFLAG_DSYNC`](#fdflags.dsync). 1888 1889- <a href="#rights.fd_tell" name="rights.fd_tell"></a>**`__WASI_RIGHT_FD_TELL`** 1890 1891 The right to invoke [`__wasi_fd_seek()`](#fd_seek) in such a way that the 1892 file offset remains unaltered (i.e., [`__WASI_WHENCE_CUR`](#whence.cur) with 1893 offset zero), or to invoke [`__wasi_fd_tell()`](#fd_tell). 1894 1895- <a href="#rights.fd_write" name="rights.fd_write"></a>**`__WASI_RIGHT_FD_WRITE`** 1896 1897 The right to invoke [`__wasi_fd_write()`](#fd_write) and [`__wasi_sock_send()`](#sock_send). 1898 1899 If [`__WASI_RIGHT_FD_SEEK`](#rights.fd_seek) is set, includes the right to 1900 invoke [`__wasi_fd_pwrite()`](#fd_pwrite). 1901 1902- <a href="#rights.fd_advise" name="rights.fd_advise"></a>**`__WASI_RIGHT_FD_ADVISE`** 1903 1904 The right to invoke [`__wasi_fd_advise()`](#fd_advise). 1905 1906- <a href="#rights.fd_allocate" name="rights.fd_allocate"></a>**`__WASI_RIGHT_FD_ALLOCATE`** 1907 1908 The right to invoke [`__wasi_fd_allocate()`](#fd_allocate). 1909 1910- <a href="#rights.path_create_directory" name="rights.path_create_directory"></a>**`__WASI_RIGHT_PATH_CREATE_DIRECTORY`** 1911 1912 The right to invoke [`__wasi_path_create_directory()`](#path_create_directory). 1913 1914- <a href="#rights.path_create_file" name="rights.path_create_file"></a>**`__WASI_RIGHT_PATH_CREATE_FILE`** 1915 1916 If [`__WASI_RIGHT_PATH_OPEN`](#rights.path_open) is set, the right to invoke 1917 [`__wasi_path_open()`](#path_open) with [`__WASI_O_CREAT`](#oflags.creat). 1918 1919- <a href="#rights.path_link_source" name="rights.path_link_source"></a>**`__WASI_RIGHT_PATH_LINK_SOURCE`** 1920 1921 The right to invoke [`__wasi_path_link()`](#path_link) with the file 1922 descriptor as the source directory. 1923 1924- <a href="#rights.path_link_target" name="rights.path_link_target"></a>**`__WASI_RIGHT_PATH_LINK_TARGET`** 1925 1926 The right to invoke [`__wasi_path_link()`](#path_link) with the file 1927 descriptor as the target directory. 1928 1929- <a href="#rights.path_open" name="rights.path_open"></a>**`__WASI_RIGHT_PATH_OPEN`** 1930 1931 The right to invoke [`__wasi_path_open()`](#path_open). 1932 1933- <a href="#rights.fd_readdir" name="rights.fd_readdir"></a>**`__WASI_RIGHT_FD_READDIR`** 1934 1935 The right to invoke [`__wasi_fd_readdir()`](#fd_readdir). 1936 1937- <a href="#rights.path_readlink" name="rights.path_readlink"></a>**`__WASI_RIGHT_PATH_READLINK`** 1938 1939 The right to invoke [`__wasi_path_readlink()`](#path_readlink). 1940 1941- <a href="#rights.path_rename_source" name="rights.path_rename_source"></a>**`__WASI_RIGHT_PATH_RENAME_SOURCE`** 1942 1943 The right to invoke [`__wasi_path_rename()`](#path_rename) with the file 1944 descriptor as the source directory. 1945 1946- <a href="#rights.path_rename_target" name="rights.path_rename_target"></a>**`__WASI_RIGHT_PATH_RENAME_TARGET`** 1947 1948 The right to invoke [`__wasi_path_rename()`](#path_rename) with the file 1949 descriptor as the target directory. 1950 1951- <a href="#rights.path_filestat_get" name="rights.path_filestat_get"></a>**`__WASI_RIGHT_PATH_FILESTAT_GET`** 1952 1953 The right to invoke [`__wasi_path_filestat_get()`](#path_filestat_get). 1954 1955- <a href="#rights.path_filestat_set_size" name="rights.path_filestat_set_size"></a>**`__WASI_RIGHT_PATH_FILESTAT_SET_SIZE`** 1956 1957 The right to change a file's size (there is no `__wasi_path_filestat_set_size()`). 1958 1959 If [`__WASI_RIGHT_PATH_OPEN`](#rights.path_open) is set, includes the right to 1960 invoke [`__wasi_path_open()`](#path_open) with [`__WASI_O_TRUNC`](#oflags.trunc). 1961 1962- <a href="#rights.path_filestat_set_times" name="rights.path_filestat_set_times"></a>**`__WASI_RIGHT_PATH_FILESTAT_SET_TIMES`** 1963 1964 The right to invoke [`__wasi_path_filestat_set_times()`](#path_filestat_set_times). 1965 1966- <a href="#rights.fd_filestat_get" name="rights.fd_filestat_get"></a>**`__WASI_RIGHT_FD_FILESTAT_GET`** 1967 1968 The right to invoke [`__wasi_fd_filestat_get()`](#fd_filestat_get). 1969 1970- <a href="#rights.fd_filestat_set_size" name="rights.fd_filestat_set_size"></a>**`__WASI_RIGHT_FD_FILESTAT_SET_SIZE`** 1971 1972 The right to invoke [`__wasi_fd_filestat_set_size()`](#fd_filestat_set_size). 1973 1974- <a href="#rights.fd_filestat_set_times" name="rights.fd_filestat_set_times"></a>**`__WASI_RIGHT_FD_FILESTAT_SET_TIMES`** 1975 1976 The right to invoke [`__wasi_fd_filestat_set_times()`](#fd_filestat_set_times). 1977 1978- <a href="#rights.path_symlink" name="rights.path_symlink"></a>**`__WASI_RIGHT_PATH_SYMLINK`** 1979 1980 The right to invoke [`__wasi_path_symlink()`](#path_symlink). 1981 1982- <a href="#rights.path_unlink_file" name="rights.path_unlink_file"></a>**`__WASI_RIGHT_PATH_UNLINK_FILE`** 1983 1984 The right to invoke [`__wasi_path_unlink_file()`](#path_unlink_file). 1985 1986- <a href="#rights.path_remove_directory" name="rights.path_remove_directory"></a>**`__WASI_RIGHT_PATH_REMOVE_DIRECTORY`** 1987 1988 The right to invoke [`__wasi_path_remove_directory()`](#path_remove_directory). 1989 1990- <a href="#rights.poll_fd_readwrite" name="rights.poll_fd_readwrite"></a>**`__WASI_RIGHT_POLL_FD_READWRITE`** 1991 1992 If [`__WASI_RIGHT_FD_READ`](#rights.fd_read) is set, includes the right to 1993 invoke [`__wasi_poll_oneoff()`](#poll_oneoff) to subscribe to [`__WASI_EVENTTYPE_FD_READ`](#eventtype.fd_read). 1994 1995 If [`__WASI_RIGHT_FD_WRITE`](#rights.fd_write) is set, includes the right to 1996 invoke [`__wasi_poll_oneoff()`](#poll_oneoff) to subscribe to [`__WASI_EVENTTYPE_FD_WRITE`](#eventtype.fd_write). 1997 1998- <a href="#rights.sock_shutdown" name="rights.sock_shutdown"></a>**`__WASI_RIGHT_SOCK_SHUTDOWN`** 1999 2000 The right to invoke [`__wasi_sock_shutdown()`](#sock_shutdown). 2001 2002### <a href="#roflags" name="roflags"></a>`__wasi_roflags_t` (`uint16_t` bitfield) 2003 2004Flags returned by [`__wasi_sock_recv()`](#sock_recv). 2005 2006Used by [`__wasi_sock_recv()`](#sock_recv). 2007 2008Possible values: 2009 2010- <a href="#roflags.data_truncated" name="roflags.data_truncated"></a>**`__WASI_SOCK_RECV_DATA_TRUNCATED`** 2011 2012 Returned by [`__wasi_sock_recv()`](#sock_recv): Message data has been 2013 truncated. 2014 2015### <a href="#sdflags" name="sdflags"></a>`__wasi_sdflags_t` (`uint8_t` bitfield) 2016 2017Which channels on a socket to shut down. 2018 2019Used by [`__wasi_sock_shutdown()`](#sock_shutdown). 2020 2021Possible values: 2022 2023- <a href="#sdflags.rd" name="sdflags.rd"></a>**`__WASI_SHUT_RD`** 2024 2025 Disables further receive operations. 2026 2027- <a href="#sdflags.wr" name="sdflags.wr"></a>**`__WASI_SHUT_WR`** 2028 2029 Disables further send operations. 2030 2031### <a href="#siflags" name="siflags"></a>`__wasi_siflags_t` (`uint16_t` bitfield) 2032 2033Flags provided to [`__wasi_sock_send()`](#sock_send). As there are currently no flags 2034defined, it must be set to zero. 2035 2036Used by [`__wasi_sock_send()`](#sock_send). 2037 2038### <a href="#signal" name="signal"></a>`__wasi_signal_t` (`uint8_t`) 2039 2040Signal condition. 2041 2042Used by [`__wasi_proc_raise()`](#proc_raise). 2043 2044Possible values: 2045 2046- <a href="#signal.abrt" name="signal.abrt"></a>**`__WASI_SIGABRT`** 2047 2048 Process abort signal. 2049 2050 Action: Terminates the process. 2051 2052- <a href="#signal.alrm" name="signal.alrm"></a>**`__WASI_SIGALRM`** 2053 2054 Alarm clock. 2055 2056 Action: Terminates the process. 2057 2058- <a href="#signal.bus" name="signal.bus"></a>**`__WASI_SIGBUS`** 2059 2060 Access to an undefined portion of a memory object. 2061 2062 Action: Terminates the process. 2063 2064- <a href="#signal.chld" name="signal.chld"></a>**`__WASI_SIGCHLD`** 2065 2066 Child process terminated, stopped, or continued. 2067 2068 Action: Ignored. 2069 2070- <a href="#signal.cont" name="signal.cont"></a>**`__WASI_SIGCONT`** 2071 2072 Continue executing, if stopped. 2073 2074 Action: Continues executing, if stopped. 2075 2076- <a href="#signal.fpe" name="signal.fpe"></a>**`__WASI_SIGFPE`** 2077 2078 Erroneous arithmetic operation. 2079 2080 Action: Terminates the process. 2081 2082- <a href="#signal.hup" name="signal.hup"></a>**`__WASI_SIGHUP`** 2083 2084 Hangup. 2085 2086 Action: Terminates the process. 2087 2088- <a href="#signal.ill" name="signal.ill"></a>**`__WASI_SIGILL`** 2089 2090 Illegal instruction. 2091 2092 Action: Terminates the process. 2093 2094- <a href="#signal.int" name="signal.int"></a>**`__WASI_SIGINT`** 2095 2096 Terminate interrupt signal. 2097 2098 Action: Terminates the process. 2099 2100- <a href="#signal.kill" name="signal.kill"></a>**`__WASI_SIGKILL`** 2101 2102 Kill. 2103 2104 Action: Terminates the process. 2105 2106- <a href="#signal.pipe" name="signal.pipe"></a>**`__WASI_SIGPIPE`** 2107 2108 Write on a pipe with no one to read it. 2109 2110 Action: Ignored. 2111 2112- <a href="#signal.quit" name="signal.quit"></a>**`__WASI_SIGQUIT`** 2113 2114 Terminal quit signal. 2115 2116 Action: Terminates the process. 2117 2118- <a href="#signal.segv" name="signal.segv"></a>**`__WASI_SIGSEGV`** 2119 2120 Invalid memory reference. 2121 2122 Action: Terminates the process. 2123 2124- <a href="#signal.stop" name="signal.stop"></a>**`__WASI_SIGSTOP`** 2125 2126 Stop executing. 2127 2128 Action: Stops executing. 2129 2130- <a href="#signal.sys" name="signal.sys"></a>**`__WASI_SIGSYS`** 2131 2132 Bad system call. 2133 2134 Action: Terminates the process. 2135 2136- <a href="#signal.term" name="signal.term"></a>**`__WASI_SIGTERM`** 2137 2138 Termination signal. 2139 2140 Action: Terminates the process. 2141 2142- <a href="#signal.trap" name="signal.trap"></a>**`__WASI_SIGTRAP`** 2143 2144 Trace/breakpoint trap. 2145 2146 Action: Terminates the process. 2147 2148- <a href="#signal.tstp" name="signal.tstp"></a>**`__WASI_SIGTSTP`** 2149 2150 Terminal stop signal. 2151 2152 Action: Stops executing. 2153 2154- <a href="#signal.ttin" name="signal.ttin"></a>**`__WASI_SIGTTIN`** 2155 2156 Background process attempting read. 2157 2158 Action: Stops executing. 2159 2160- <a href="#signal.ttou" name="signal.ttou"></a>**`__WASI_SIGTTOU`** 2161 2162 Background process attempting write. 2163 2164 Action: Stops executing. 2165 2166- <a href="#signal.urg" name="signal.urg"></a>**`__WASI_SIGURG`** 2167 2168 High bandwidth data is available at a socket. 2169 2170 Action: Ignored. 2171 2172- <a href="#signal.usr1" name="signal.usr1"></a>**`__WASI_SIGUSR1`** 2173 2174 User-defined signal 1. 2175 2176 Action: Terminates the process. 2177 2178- <a href="#signal.usr2" name="signal.usr2"></a>**`__WASI_SIGUSR2`** 2179 2180 User-defined signal 2. 2181 2182 Action: Terminates the process. 2183 2184- <a href="#signal.vtalrm" name="signal.vtalrm"></a>**`__WASI_SIGVTALRM`** 2185 2186 Virtual timer expired. 2187 2188 Action: Terminates the process. 2189 2190- <a href="#signal.xcpu" name="signal.xcpu"></a>**`__WASI_SIGXCPU`** 2191 2192 CPU time limit exceeded. 2193 2194 Action: Terminates the process. 2195 2196- <a href="#signal.xfsz" name="signal.xfsz"></a>**`__WASI_SIGXFSZ`** 2197 2198 File size limit exceeded. 2199 2200 Action: Terminates the process. 2201 2202### <a href="#subclockflags" name="subclockflags"></a>`__wasi_subclockflags_t` (`uint16_t` bitfield) 2203 2204Flags determining how to interpret the timestamp provided in 2205[`__wasi_subscription_t::u.clock.timeout`](#subscription.u.clock.timeout). 2206 2207Used by [`__wasi_subscription_t`](#subscription). 2208 2209Possible values: 2210 2211- <a href="#subclockflags.abstime" name="subclockflags.abstime"></a>**`__WASI_SUBSCRIPTION_CLOCK_ABSTIME`** 2212 2213 If set, treat the timestamp provided in 2214 [`__wasi_subscription_t::u.clock.timeout`](#subscription.u.clock.timeout) as an absolute timestamp 2215 of clock [`__wasi_subscription_t::u.clock.clock_id`](#subscription.u.clock.clock_id). 2216 2217 If clear, treat the timestamp provided in 2218 [`__wasi_subscription_t::u.clock.timeout`](#subscription.u.clock.timeout) relative to the current 2219 time value of clock [`__wasi_subscription_t::u.clock.clock_id`](#subscription.u.clock.clock_id). 2220 2221### <a href="#subscription" name="subscription"></a>`__wasi_subscription_t` (`struct`) 2222 2223Subscription to an event. 2224 2225Used by [`__wasi_poll_oneoff()`](#poll_oneoff). 2226 2227Members: 2228 2229- <a href="#subscription.userdata" name="subscription.userdata"></a><code>[\_\_wasi\_userdata\_t](#userdata) <strong>userdata</strong></code> 2230 2231 User-provided value that is attached to the subscription in the 2232 implementation and returned through 2233 [`__wasi_event_t::userdata`](#event.userdata). 2234 2235- <a href="#subscription.type" name="subscription.type"></a><code>[\_\_wasi\_eventtype\_t](#eventtype) <strong>type</strong></code> 2236 2237 The type of the event to which to subscribe. 2238 2239- When `type` is [`__WASI_EVENTTYPE_CLOCK`](#eventtype.u.clock): 2240 2241 - <a href="#subscription.u.clock" name="subscription.u.clock"></a>**`u.clock`** 2242 2243 - <a href="#subscription.u.clock.identifier" name="subscription.u.clock.identifier"></a><code>[\_\_wasi\_userdata\_t](#userdata) <strong>identifier</strong></code> 2244 2245 The user-defined unique identifier of the clock. 2246 2247 - <a href="#subscription.u.clock.clock_id" name="subscription.u.clock.clock_id"></a><code>[\_\_wasi\_clockid\_t](#clockid) <strong>clock\_id</strong></code> 2248 2249 The clock against which to compare the timestamp. 2250 2251 - <a href="#subscription.u.clock.timeout" name="subscription.u.clock.timeout"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>timeout</strong></code> 2252 2253 The absolute or relative timestamp. 2254 2255 - <a href="#subscription.u.clock.precision" name="subscription.u.clock.precision"></a><code>[\_\_wasi\_timestamp\_t](#timestamp) <strong>precision</strong></code> 2256 2257 The amount of time that the implementation may wait additionally 2258 to coalesce with other events. 2259 2260 - <a href="#subscription.u.clock.flags" name="subscription.u.clock.flags"></a><code>[\_\_wasi\_subclockflags\_t](#subclockflags) <strong>flags</strong></code> 2261 2262 Flags specifying whether the timeout is absolute or relative. 2263 2264- When `type` is [`__WASI_EVENTTYPE_FD_READ`](#eventtype.fd_read) or [`__WASI_EVENTTYPE_FD_WRITE`](#eventtype.fd_write): 2265 2266 - <a href="#subscription.u.fd_readwrite" name="subscription.u.fd_readwrite"></a>**`u.fd_readwrite`** 2267 2268 - <a href="#subscription.u.fd_readwrite.fd" name="subscription.u.fd_readwrite.fd"></a><code>[\_\_wasi\_fd\_t](#fd) <strong>fd</strong></code> 2269 2270 The file descriptor on which to wait for it to become ready 2271 for reading or writing. 2272 2273### <a href="#timestamp" name="timestamp"></a>`__wasi_timestamp_t` (`uint64_t`) 2274 2275Timestamp in nanoseconds. 2276 2277Used by [`__wasi_filestat_t`](#filestat), [`__wasi_subscription_t`](#subscription), [`__wasi_clock_res_get()`](#clock_res_get), [`__wasi_clock_time_get()`](#clock_time_get), [`__wasi_fd_filestat_set_times()`](#fd_filestat_set_times), and [`__wasi_path_filestat_set_times()`](#path_filestat_set_times). 2278 2279### <a href="#userdata" name="userdata"></a>`__wasi_userdata_t` (`uint64_t`) 2280 2281User-provided value that may be attached to objects that is 2282retained when extracted from the implementation. 2283 2284Used by [`__wasi_event_t`](#event) and [`__wasi_subscription_t`](#subscription). 2285 2286### <a href="#whence" name="whence"></a>`__wasi_whence_t` (`uint8_t`) 2287 2288The position relative to which to set the offset of the file descriptor. 2289 2290Used by [`__wasi_fd_seek()`](#fd_seek). 2291 2292Possible values: 2293 2294- <a href="#whence.cur" name="whence.cur"></a>**`__WASI_WHENCE_CUR`** 2295 2296 Seek relative to current position. 2297 2298- <a href="#whence.end" name="whence.end"></a>**`__WASI_WHENCE_END`** 2299 2300 Seek relative to end-of-file. 2301 2302- <a href="#whence.set" name="whence.set"></a>**`__WASI_WHENCE_SET`** 2303 2304 Seek relative to start-of-file. 2305 2306