Mercurial
diff third_party/libuv/docs/src/fs.rst @ 160:948de3f54cea
[ThirdParty] Added libuv
| author | June Park <parkjune1995@gmail.com> |
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| date | Wed, 14 Jan 2026 19:39:52 -0800 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/third_party/libuv/docs/src/fs.rst Wed Jan 14 19:39:52 2026 -0800 @@ -0,0 +1,727 @@ + +.. _fs: + +File system operations +====================== + +libuv provides a wide variety of cross-platform sync and async file system +operations. All functions defined in this document take a callback, which is +allowed to be NULL. If the callback is NULL the request is completed synchronously, +otherwise it will be performed asynchronously. + +All file operations are run on the threadpool. See :ref:`threadpool` for information +on the threadpool size. + +Starting with libuv v1.45.0, some file operations on Linux are handed off to +`io_uring <https://en.wikipedia.org/wiki/Io_uring>` when possible. Apart from +a (sometimes significant) increase in throughput there should be no change in +observable behavior. Libuv reverts to using its threadpool when the necessary +kernel features are unavailable or unsuitable. Starting with libuv v1.49.0 this +behavior was reverted and Libuv on Linux by default will be using the threadpool +again. In order to enable io_uring the :c:type:`uv_loop_t` instance must be +configured with the :c:type:`UV_LOOP_ENABLE_IO_URING_SQPOLL` option. + +.. note:: + On Windows `uv_fs_*` functions use utf-8 encoding. + +Data types +---------- + +.. c:type:: uv_fs_t + + File system request type. + +.. c:type:: uv_timespec_t + + Y2K38-unsafe data type for storing times with nanosecond resolution. + Will be replaced with :c:type:`uv_timespec64_t` in libuv v2.0. + + :: + + typedef struct { + long tv_sec; + long tv_nsec; + } uv_timespec_t; + +.. c:type:: uv_stat_t + + Portable equivalent of ``struct stat``. + + :: + + typedef struct { + uint64_t st_dev; + uint64_t st_mode; + uint64_t st_nlink; + uint64_t st_uid; + uint64_t st_gid; + uint64_t st_rdev; + uint64_t st_ino; + uint64_t st_size; + uint64_t st_blksize; + uint64_t st_blocks; + uint64_t st_flags; + uint64_t st_gen; + uv_timespec_t st_atim; + uv_timespec_t st_mtim; + uv_timespec_t st_ctim; + uv_timespec_t st_birthtim; + } uv_stat_t; + +.. c:enum:: uv_fs_type + + File system request type. + + :: + + typedef enum { + UV_FS_UNKNOWN = -1, + UV_FS_CUSTOM, + UV_FS_OPEN, + UV_FS_CLOSE, + UV_FS_READ, + UV_FS_WRITE, + UV_FS_SENDFILE, + UV_FS_STAT, + UV_FS_LSTAT, + UV_FS_FSTAT, + UV_FS_FTRUNCATE, + UV_FS_UTIME, + UV_FS_FUTIME, + UV_FS_ACCESS, + UV_FS_CHMOD, + UV_FS_FCHMOD, + UV_FS_FSYNC, + UV_FS_FDATASYNC, + UV_FS_UNLINK, + UV_FS_RMDIR, + UV_FS_MKDIR, + UV_FS_MKDTEMP, + UV_FS_RENAME, + UV_FS_SCANDIR, + UV_FS_LINK, + UV_FS_SYMLINK, + UV_FS_READLINK, + UV_FS_CHOWN, + UV_FS_FCHOWN, + UV_FS_REALPATH, + UV_FS_COPYFILE, + UV_FS_LCHOWN, + UV_FS_OPENDIR, + UV_FS_READDIR, + UV_FS_CLOSEDIR, + UV_FS_MKSTEMP, + UV_FS_LUTIME + } uv_fs_type; + +.. c:type:: uv_statfs_t + + Reduced cross platform equivalent of ``struct statfs``. + Used in :c:func:`uv_fs_statfs`. + + :: + + typedef struct uv_statfs_s { + uint64_t f_type; + uint64_t f_bsize; + uint64_t f_blocks; + uint64_t f_bfree; + uint64_t f_bavail; + uint64_t f_files; + uint64_t f_ffree; + uint64_t f_spare[4]; + } uv_statfs_t; + +.. c:enum:: uv_dirent_type_t + + Type of dirent. + + :: + + typedef enum { + UV_DIRENT_UNKNOWN, + UV_DIRENT_FILE, + UV_DIRENT_DIR, + UV_DIRENT_LINK, + UV_DIRENT_FIFO, + UV_DIRENT_SOCKET, + UV_DIRENT_CHAR, + UV_DIRENT_BLOCK + } uv_dirent_type_t; + + +.. c:type:: uv_dirent_t + + Cross platform (reduced) equivalent of ``struct dirent``. + Used in :c:func:`uv_fs_scandir_next`. + + :: + + typedef struct uv_dirent_s { + const char* name; + uv_dirent_type_t type; + } uv_dirent_t; + +.. c:type:: uv_dir_t + + Data type used for streaming directory iteration. + Used by :c:func:`uv_fs_opendir()`, :c:func:`uv_fs_readdir()`, and + :c:func:`uv_fs_closedir()`. `dirents` represents a user provided array of + `uv_dirent_t`s used to hold results. `nentries` is the user provided maximum + array size of `dirents`. + + :: + + typedef struct uv_dir_s { + uv_dirent_t* dirents; + size_t nentries; + } uv_dir_t; + +.. c:type:: void (*uv_fs_cb)(uv_fs_t* req) + + Callback called when a request is completed asynchronously. + + +Public members +^^^^^^^^^^^^^^ + +.. c:member:: uv_loop_t* uv_fs_t.loop + + Loop that started this request and where completion will be reported. + Readonly. + +.. c:member:: uv_fs_type uv_fs_t.fs_type + + FS request type. + +.. c:member:: const char* uv_fs_t.path + + Path affecting the request. + +.. c:member:: ssize_t uv_fs_t.result + + Result of the request. < 0 means error, success otherwise. On requests such + as :c:func:`uv_fs_read` or :c:func:`uv_fs_write` it indicates the amount of + data that was read or written, respectively. + +.. c:member:: uv_stat_t uv_fs_t.statbuf + + Stores the result of :c:func:`uv_fs_stat` and other stat requests. + +.. c:member:: void* uv_fs_t.ptr + + Stores the result of :c:func:`uv_fs_readlink` and + :c:func:`uv_fs_realpath` and serves as an alias to `statbuf`. + +.. seealso:: The :c:type:`uv_req_t` members also apply. + + +API +--- + +.. c:function:: void uv_fs_req_cleanup(uv_fs_t* req) + + Cleanup request. Must be called after a request is finished to deallocate + any memory libuv might have allocated. + +.. c:function:: int uv_fs_close(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_fs_cb cb) + + Equivalent to :man:`close(2)`. + +.. c:function:: int uv_fs_open(uv_loop_t* loop, uv_fs_t* req, const char* path, int flags, int mode, uv_fs_cb cb) + + Equivalent to :man:`open(2)`. + + .. note:: + On Windows libuv uses `CreateFileW` and thus the file is always opened + in binary mode. Because of this the O_BINARY and O_TEXT flags are not + supported. + +.. c:function:: int uv_fs_read(uv_loop_t* loop, uv_fs_t* req, uv_file file, const uv_buf_t bufs[], unsigned int nbufs, int64_t offset, uv_fs_cb cb) + + Equivalent to :man:`preadv(2)`. If the `offset` argument is `-1`, then + the current file offset is used and updated. + + .. warning:: + On Windows, under non-MSVC environments (e.g. when GCC or Clang is used + to build libuv), files opened using ``UV_FS_O_FILEMAP`` may cause a fatal + crash if the memory mapped read operation fails. + +.. c:function:: int uv_fs_unlink(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) + + Equivalent to :man:`unlink(2)`. + +.. c:function:: int uv_fs_write(uv_loop_t* loop, uv_fs_t* req, uv_file file, const uv_buf_t bufs[], unsigned int nbufs, int64_t offset, uv_fs_cb cb) + + Equivalent to :man:`pwritev(2)`. If the `offset` argument is `-1`, then + the current file offset is used and updated. + + .. warning:: + On Windows, under non-MSVC environments (e.g. when GCC or Clang is used + to build libuv), files opened using ``UV_FS_O_FILEMAP`` may cause a fatal + crash if the memory mapped write operation fails. + +.. c:function:: int uv_fs_mkdir(uv_loop_t* loop, uv_fs_t* req, const char* path, int mode, uv_fs_cb cb) + + Equivalent to :man:`mkdir(2)`. + + .. note:: + `mode` is currently not implemented on Windows. + +.. c:function:: int uv_fs_mkdtemp(uv_loop_t* loop, uv_fs_t* req, const char* tpl, uv_fs_cb cb) + + Equivalent to :man:`mkdtemp(3)`. The result can be found as a null terminated string at `req->path`. + +.. c:function:: int uv_fs_mkstemp(uv_loop_t* loop, uv_fs_t* req, const char* tpl, uv_fs_cb cb) + + Equivalent to :man:`mkstemp(3)`. The created file path can be found as a null terminated string at `req->path`. + The file descriptor can be found as an integer at `req->result`. + + .. versionadded:: 1.34.0 + +.. c:function:: int uv_fs_rmdir(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) + + Equivalent to :man:`rmdir(2)`. + +.. c:function:: int uv_fs_opendir(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) + + Opens `path` as a directory stream. On success, a `uv_dir_t` is allocated + and returned via `req->ptr`. This memory is not freed by + `uv_fs_req_cleanup()`, although `req->ptr` is set to `NULL`. The allocated + memory must be freed by calling `uv_fs_closedir()`. On failure, no memory + is allocated. + + The contents of the directory can be iterated over by passing the resulting + `uv_dir_t` to `uv_fs_readdir()`. + + .. versionadded:: 1.28.0 + +.. c:function:: int uv_fs_closedir(uv_loop_t* loop, uv_fs_t* req, uv_dir_t* dir, uv_fs_cb cb) + + Closes the directory stream represented by `dir` and frees the memory + allocated by `uv_fs_opendir()`. + + .. versionadded:: 1.28.0 + +.. c:function:: int uv_fs_readdir(uv_loop_t* loop, uv_fs_t* req, uv_dir_t* dir, uv_fs_cb cb) + + Iterates over the directory stream, `dir`, returned by a successful + `uv_fs_opendir()` call. Prior to invoking `uv_fs_readdir()`, the caller + must set `dir->dirents` and `dir->nentries`, representing the array of + :c:type:`uv_dirent_t` elements used to hold the read directory entries and + its size. + + On success, the result is an integer >= 0 representing the number of entries + read from the stream. + + .. versionadded:: 1.28.0 + + .. warning:: + `uv_fs_readdir()` is not thread safe. + + .. note:: + This function does not return the "." and ".." entries. + + .. note:: + On success this function allocates memory that must be freed using + `uv_fs_req_cleanup()`. `uv_fs_req_cleanup()` must be called before + closing the directory with `uv_fs_closedir()`. + +.. c:function:: int uv_fs_scandir(uv_loop_t* loop, uv_fs_t* req, const char* path, int flags, uv_fs_cb cb) +.. c:function:: int uv_fs_scandir_next(uv_fs_t* req, uv_dirent_t* ent) + + Equivalent to :man:`scandir(3)`, with a slightly different API. Once the callback + for the request is called, the user can use :c:func:`uv_fs_scandir_next` to + get `ent` populated with the next directory entry data. When there are no + more entries ``UV_EOF`` will be returned. + + .. note:: + Unlike `scandir(3)`, this function does not return the "." and ".." entries. + + .. note:: + On Linux, getting the type of an entry is only supported by some file systems (btrfs, ext2, + ext3 and ext4 at the time of this writing), check the :man:`getdents(2)` man page. + +.. c:function:: int uv_fs_stat(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) +.. c:function:: int uv_fs_fstat(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_fs_cb cb) +.. c:function:: int uv_fs_lstat(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) + + Equivalent to :man:`stat(2)`, :man:`fstat(2)` and :man:`lstat(2)` respectively. + +.. c:function:: int uv_fs_statfs(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) + + Equivalent to :man:`statfs(2)`. On success, a `uv_statfs_t` is allocated + and returned via `req->ptr`. This memory is freed by `uv_fs_req_cleanup()`. + + .. note:: + Any fields in the resulting `uv_statfs_t` that are not supported by the + underlying operating system are set to zero. + + .. versionadded:: 1.31.0 + +.. c:function:: int uv_fs_rename(uv_loop_t* loop, uv_fs_t* req, const char* path, const char* new_path, uv_fs_cb cb) + + Equivalent to :man:`rename(2)`. + +.. c:function:: int uv_fs_fsync(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_fs_cb cb) + + Equivalent to :man:`fsync(2)`. + + .. note:: + For AIX, `uv_fs_fsync` returns `UV_EBADF` on file descriptors referencing + non regular files. + +.. c:function:: int uv_fs_fdatasync(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_fs_cb cb) + + Equivalent to :man:`fdatasync(2)`. + +.. c:function:: int uv_fs_ftruncate(uv_loop_t* loop, uv_fs_t* req, uv_file file, int64_t offset, uv_fs_cb cb) + + Equivalent to :man:`ftruncate(2)`. + +.. c:function:: int uv_fs_copyfile(uv_loop_t* loop, uv_fs_t* req, const char* path, const char* new_path, int flags, uv_fs_cb cb) + + Copies a file from `path` to `new_path`. Supported `flags` are described below. + + - `UV_FS_COPYFILE_EXCL`: If present, `uv_fs_copyfile()` will fail with + `UV_EEXIST` if the destination path already exists. The default behavior + is to overwrite the destination if it exists. + - `UV_FS_COPYFILE_FICLONE`: If present, `uv_fs_copyfile()` will attempt to + create a copy-on-write reflink. If the underlying platform does not + support copy-on-write, or an error occurs while attempting to use + copy-on-write, a fallback copy mechanism based on + :c:func:`uv_fs_sendfile()` is used. + - `UV_FS_COPYFILE_FICLONE_FORCE`: If present, `uv_fs_copyfile()` will + attempt to create a copy-on-write reflink. If the underlying platform does + not support copy-on-write, or an error occurs while attempting to use + copy-on-write, then an error is returned. + + .. warning:: + If the destination path is created, but an error occurs while copying + the data, then the destination path is removed. There is a brief window + of time between closing and removing the file where another process + could access the file. + + .. versionadded:: 1.14.0 + + .. versionchanged:: 1.20.0 `UV_FS_COPYFILE_FICLONE` and + `UV_FS_COPYFILE_FICLONE_FORCE` are supported. + + .. versionchanged:: 1.33.0 If an error occurs while using + `UV_FS_COPYFILE_FICLONE_FORCE`, that error is returned. Previously, + all errors were mapped to `UV_ENOTSUP`. + +.. c:function:: int uv_fs_sendfile(uv_loop_t* loop, uv_fs_t* req, uv_file out_fd, uv_file in_fd, int64_t in_offset, size_t length, uv_fs_cb cb) + + Limited equivalent to :man:`sendfile(2)`. + +.. c:function:: int uv_fs_access(uv_loop_t* loop, uv_fs_t* req, const char* path, int mode, uv_fs_cb cb) + + Equivalent to :man:`access(2)` on Unix. Windows uses ``GetFileAttributesW()``. + +.. c:function:: int uv_fs_chmod(uv_loop_t* loop, uv_fs_t* req, const char* path, int mode, uv_fs_cb cb) +.. c:function:: int uv_fs_fchmod(uv_loop_t* loop, uv_fs_t* req, uv_file file, int mode, uv_fs_cb cb) + + Equivalent to :man:`chmod(2)` and :man:`fchmod(2)` respectively. + +.. c:function:: int uv_fs_utime(uv_loop_t* loop, uv_fs_t* req, const char* path, double atime, double mtime, uv_fs_cb cb) +.. c:function:: int uv_fs_futime(uv_loop_t* loop, uv_fs_t* req, uv_file file, double atime, double mtime, uv_fs_cb cb) +.. c:function:: int uv_fs_lutime(uv_loop_t* loop, uv_fs_t* req, const char* path, double atime, double mtime, uv_fs_cb cb) + + Equivalent to :man:`utime(2)`, :man:`futimes(3)` and :man:`lutimes(3)` respectively. + + Passing `UV_FS_UTIME_NOW` as the atime or mtime sets the timestamp to the + current time. + + Passing `UV_FS_UTIME_OMIT` as the atime or mtime leaves the timestamp + untouched. + + .. note:: + z/OS: `uv_fs_lutime()` is not implemented for z/OS. It can still be called but will return + ``UV_ENOSYS``. + + .. note:: + AIX: `uv_fs_futime()` and `uv_fs_lutime()` functions only work for AIX 7.1 and newer. + They can still be called on older versions but will return ``UV_ENOSYS``. + + .. versionchanged:: 1.10.0 sub-second precission is supported on Windows + +.. c:function:: int uv_fs_link(uv_loop_t* loop, uv_fs_t* req, const char* path, const char* new_path, uv_fs_cb cb) + + Equivalent to :man:`link(2)`. + +.. c:function:: int uv_fs_symlink(uv_loop_t* loop, uv_fs_t* req, const char* path, const char* new_path, int flags, uv_fs_cb cb) + + Equivalent to :man:`symlink(2)`. + + .. note:: + On Windows the `flags` parameter can be specified to control how the symlink will + be created: + + * ``UV_FS_SYMLINK_DIR``: indicates that `path` points to a directory. + + * ``UV_FS_SYMLINK_JUNCTION``: request that the symlink is created + using junction points. + +.. c:function:: int uv_fs_readlink(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) + + Equivalent to :man:`readlink(2)`. + The resulting string is stored in `req->ptr`. + +.. c:function:: int uv_fs_realpath(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_fs_cb cb) + + Equivalent to :man:`realpath(3)` on Unix. Windows uses `GetFinalPathNameByHandleW <https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getfinalpathnamebyhandlew>`_. + The resulting string is stored in `req->ptr`. + + .. warning:: + This function has certain platform-specific caveats that were discovered when used in Node. + + * macOS and other BSDs: this function will fail with UV_ELOOP if more than 32 symlinks are + found while resolving the given path. This limit is hardcoded and cannot be sidestepped. + * Windows: while this function works in the common case, there are a number of corner cases + where it doesn't: + + - Paths in ramdisk volumes created by tools which sidestep the Volume Manager (such as ImDisk) + cannot be resolved. + - Inconsistent casing when using drive letters. + - Resolved path bypasses subst'd drives. + + While this function can still be used, it's not recommended if scenarios such as the + above need to be supported. + + The background story and some more details on these issues can be checked + `here <https://github.com/nodejs/node/issues/7726>`_. + + .. versionadded:: 1.8.0 + +.. c:function:: int uv_fs_chown(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_uid_t uid, uv_gid_t gid, uv_fs_cb cb) +.. c:function:: int uv_fs_fchown(uv_loop_t* loop, uv_fs_t* req, uv_file file, uv_uid_t uid, uv_gid_t gid, uv_fs_cb cb) +.. c:function:: int uv_fs_lchown(uv_loop_t* loop, uv_fs_t* req, const char* path, uv_uid_t uid, uv_gid_t gid, uv_fs_cb cb) + + Equivalent to :man:`chown(2)`, :man:`fchown(2)` and :man:`lchown(2)` respectively. + + .. note:: + These functions are not implemented on Windows. + + .. versionchanged:: 1.21.0 implemented uv_fs_lchown + +.. c:function:: uv_fs_type uv_fs_get_type(const uv_fs_t* req) + + Returns `req->fs_type`. + + .. versionadded:: 1.19.0 + +.. c:function:: ssize_t uv_fs_get_result(const uv_fs_t* req) + + Returns `req->result`. + + .. versionadded:: 1.19.0 + +.. c:function:: int uv_fs_get_system_error(const uv_fs_t* req) + + Returns the platform specific error code - `GetLastError()` value on Windows + and `-(req->result)` on other platforms. + + .. versionadded:: 1.38.0 + +.. c:function:: void* uv_fs_get_ptr(const uv_fs_t* req) + + Returns `req->ptr`. + + .. versionadded:: 1.19.0 + +.. c:function:: const char* uv_fs_get_path(const uv_fs_t* req) + + Returns `req->path`. + + .. versionadded:: 1.19.0 + +.. c:function:: uv_stat_t* uv_fs_get_statbuf(uv_fs_t* req) + + Returns `&req->statbuf`. + + .. versionadded:: 1.19.0 + +.. seealso:: The :c:type:`uv_req_t` API functions also apply. + +Helper functions +---------------- + +.. c:function:: uv_os_fd_t uv_get_osfhandle(int fd) + + For a file descriptor in the C runtime, get the OS-dependent handle. + On UNIX, returns the ``fd`` intact. On Windows, this calls `_get_osfhandle <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/get-osfhandle?view=vs-2019>`_. + Note that the return value is still owned by the C runtime, + any attempts to close it or to use it after closing the fd may lead to malfunction. + + .. versionadded:: 1.12.0 + +.. c:function:: int uv_open_osfhandle(uv_os_fd_t os_fd) + + For a OS-dependent handle, get the file descriptor in the C runtime. + On UNIX, returns the ``os_fd`` intact. On Windows, this calls `_open_osfhandle <https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/open-osfhandle?view=vs-2019>`_. + Note that this consumes the argument, any attempts to close it or to use it + after closing the return value may lead to malfunction. + + .. versionadded:: 1.23.0 + +File open constants +------------------- + +.. c:macro:: UV_FS_O_APPEND + + The file is opened in append mode. Before each write, the file offset is + positioned at the end of the file. + +.. c:macro:: UV_FS_O_CREAT + + The file is created if it does not already exist. + +.. c:macro:: UV_FS_O_DIRECT + + File I/O is done directly to and from user-space buffers, which must be + aligned. Buffer size and address should be a multiple of the physical sector + size of the block device. + + .. note:: + `UV_FS_O_DIRECT` is supported on Linux, and on Windows via + `FILE_FLAG_NO_BUFFERING <https://docs.microsoft.com/en-us/windows/win32/fileio/file-buffering>`_. + `UV_FS_O_DIRECT` is not supported on macOS. + +.. c:macro:: UV_FS_O_DIRECTORY + + If the path is not a directory, fail the open. + + .. note:: + `UV_FS_O_DIRECTORY` is not supported on Windows. + +.. c:macro:: UV_FS_O_DSYNC + + The file is opened for synchronous I/O. Write operations will complete once + all data and a minimum of metadata are flushed to disk. + + .. note:: + `UV_FS_O_DSYNC` is supported on Windows via + `FILE_FLAG_WRITE_THROUGH <https://docs.microsoft.com/en-us/windows/win32/fileio/file-buffering>`_. + +.. c:macro:: UV_FS_O_EXCL + + If the `O_CREAT` flag is set and the file already exists, fail the open. + + .. note:: + In general, the behavior of `O_EXCL` is undefined if it is used without + `O_CREAT`. There is one exception: on Linux 2.6 and later, `O_EXCL` can + be used without `O_CREAT` if pathname refers to a block device. If the + block device is in use by the system (e.g., mounted), the open will fail + with the error `EBUSY`. + +.. c:macro:: UV_FS_O_EXLOCK + + Atomically obtain an exclusive lock. + + .. note:: + `UV_FS_O_EXLOCK` is only supported on macOS and Windows. + + .. versionchanged:: 1.17.0 support is added for Windows. + +.. c:macro:: UV_FS_O_FILEMAP + + Use a memory file mapping to access the file. When using this flag, the + file cannot be open multiple times concurrently. + + .. note:: + `UV_FS_O_FILEMAP` is only supported on Windows. + +.. c:macro:: UV_FS_O_NOATIME + + Do not update the file access time when the file is read. + + .. note:: + `UV_FS_O_NOATIME` is not supported on Windows. + +.. c:macro:: UV_FS_O_NOCTTY + + If the path identifies a terminal device, opening the path will not cause + that terminal to become the controlling terminal for the process (if the + process does not already have one). + + .. note:: + `UV_FS_O_NOCTTY` is not supported on Windows. + +.. c:macro:: UV_FS_O_NOFOLLOW + + If the path is a symbolic link, fail the open. + + .. note:: + `UV_FS_O_NOFOLLOW` is not supported on Windows. + +.. c:macro:: UV_FS_O_NONBLOCK + + Open the file in nonblocking mode if possible. + + .. note:: + `UV_FS_O_NONBLOCK` is not supported on Windows. + +.. c:macro:: UV_FS_O_RANDOM + + Access is intended to be random. The system can use this as a hint to + optimize file caching. + + .. note:: + `UV_FS_O_RANDOM` is only supported on Windows via + `FILE_FLAG_RANDOM_ACCESS <https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew>`_. + +.. c:macro:: UV_FS_O_RDONLY + + Open the file for read-only access. + +.. c:macro:: UV_FS_O_RDWR + + Open the file for read-write access. + +.. c:macro:: UV_FS_O_SEQUENTIAL + + Access is intended to be sequential from beginning to end. The system can + use this as a hint to optimize file caching. + + .. note:: + `UV_FS_O_SEQUENTIAL` is only supported on Windows via + `FILE_FLAG_SEQUENTIAL_SCAN <https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew>`_. + +.. c:macro:: UV_FS_O_SHORT_LIVED + + The file is temporary and should not be flushed to disk if possible. + + .. note:: + `UV_FS_O_SHORT_LIVED` is only supported on Windows via + `FILE_ATTRIBUTE_TEMPORARY <https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew>`_. + +.. c:macro:: UV_FS_O_SYMLINK + + Open the symbolic link itself rather than the resource it points to. + +.. c:macro:: UV_FS_O_SYNC + + The file is opened for synchronous I/O. Write operations will complete once + all data and all metadata are flushed to disk. + + .. note:: + `UV_FS_O_SYNC` is supported on Windows via + `FILE_FLAG_WRITE_THROUGH <https://docs.microsoft.com/en-us/windows/win32/fileio/file-buffering>`_. + +.. c:macro:: UV_FS_O_TEMPORARY + + The file is temporary and should not be flushed to disk if possible. + + .. note:: + `UV_FS_O_TEMPORARY` is only supported on Windows via + `FILE_ATTRIBUTE_TEMPORARY <https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew>`_. + +.. c:macro:: UV_FS_O_TRUNC + + If the file exists and is a regular file, and the file is opened + successfully for write access, its length shall be truncated to zero. + +.. c:macro:: UV_FS_O_WRONLY + + Open the file for write-only access.