Fix At flags for real

The fix got reverted in the merge conflict but now properly fix `At`

Update posix `At` to use packed struct (I was holding back from touching
`posix` and `c` but I might as well just get this done instead of using
the deprecated constants since the diff is already big and At is worth
while)

Signed-off-by: Bernard Assan <mega.alpha100@gmail.com>

lib/std/Io/Dir.zig

@@ -24,7 +24,7 @@ pub fn cwd() Dir {
     return switch (native_os) {
         .windows => .{ .handle = std.os.windows.peb().ProcessParameters.CurrentDirectory.Handle },
         .wasi => .{ .handle = std.options.wasiCwd() },
-        else => .{ .handle = std.posix.AT.FDCWD },
+        else => .{ .handle = std.posix.At.fdcwd },
     };
 }
 

lib/std/Io/Threaded.zig

@@ -1339,12 +1339,12 @@ fn dirStatPathPosix(
     var path_buffer: [posix.PATH_MAX]u8 = undefined;
     const sub_path_posix = try pathToPosix(sub_path, &path_buffer);
 
-    const flags: u32 = if (!options.follow_symlinks) posix.AT.SYMLINK_NOFOLLOW else 0;
+    const flags: posix.At = .{ .symlink_nofollow = if (!options.follow_symlinks) true else false };
 
     while (true) {
         try t.checkCancel();
         var stat = std.mem.zeroes(posix.Stat);
-        switch (posix.errno(fstatat_sym(dir.handle, sub_path_posix, &stat, flags))) {
+        switch (posix.errno(fstatat_sym(dir.handle, sub_path_posix, &stat, @bitCast(flags)))) {
             .SUCCESS => return statFromPosix(&stat),
             .INTR => continue,
             .CANCELED => return error.Canceled,
@@ -1568,7 +1568,7 @@ fn dirAccessPosix(
     var path_buffer: [posix.PATH_MAX]u8 = undefined;
     const sub_path_posix = try pathToPosix(sub_path, &path_buffer);
 
-    const flags: u32 = @as(u32, if (!options.follow_symlinks) posix.AT.SYMLINK_NOFOLLOW else 0);
+    const flags: posix.At = .{ .symlink_nofollow = if (!options.follow_symlinks) true else false };
 
     const mode: u32 =
         @as(u32, if (options.read) posix.R_OK else 0) |
@@ -1577,7 +1577,7 @@ fn dirAccessPosix(
 
     while (true) {
         try t.checkCancel();
-        switch (posix.errno(posix.system.faccessat(dir.handle, sub_path_posix, mode, flags))) {
+        switch (posix.errno(posix.system.faccessat(dir.handle, sub_path_posix, mode, @bitCast(flags)))) {
             .SUCCESS => return,
             .INTR => continue,
             .CANCELED => return error.Canceled,
@@ -2837,7 +2837,7 @@ fn fileSeekTo(userdata: ?*anyopaque, file: Io.File, offset: u64) Io.File.SeekErr
 fn openSelfExe(userdata: ?*anyopaque, flags: Io.File.OpenFlags) Io.File.OpenSelfExeError!Io.File {
     const t: *Threaded = @ptrCast(@alignCast(userdata));
     switch (native_os) {
-        .linux, .serenity => return dirOpenFilePosix(t, .{ .handle = posix.AT.FDCWD }, "/proc/self/exe", flags),
+        .linux, .serenity => return dirOpenFilePosix(t, .{ .handle = posix.At.fdcwd }, "/proc/self/exe", flags),
         .windows => {
             // If ImagePathName is a symlink, then it will contain the path of the symlink,
             // not the path that the symlink points to. However, because we are opening

lib/std/c.zig

@@ -8375,128 +8375,267 @@ pub const port_event = switch (native_os) {
     else => void,
 };
 
-pub const AT = switch (native_os) {
+/// Deprecated Alias to `At`
-    .linux => linux.AT,
+pub const AT = At;
-    .windows => struct {
+
+pub const At = switch (native_os) {
+    .emscripten, .linux => linux.At,
+    .windows => packed struct(u32) {
+        _: u9 = 0,
         /// Remove directory instead of unlinking file
-        pub const REMOVEDIR = 0x200;
+        removedir: bool = false,
+        _11: u22 = 0,
+
+        /// DEPRECATED aliase to `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
     },
-    .driverkit, .ios, .maccatalyst, .macos, .tvos, .visionos, .watchos => struct {
+    .driverkit, .ios, .maccatalyst, .macos, .tvos, .visionos, .watchos => packed struct(u32) {
-        pub const FDCWD = -2;
+        _: u4 = 0,
         /// Use effective ids in access check
-        pub const EACCESS = 0x0010;
+        eaccess: bool = false,
         /// Act on the symlink itself not the target
-        pub const SYMLINK_NOFOLLOW = 0x0020;
+        symlink_nofollow: bool = false,
         /// Act on target of symlink
-        pub const SYMLINK_FOLLOW = 0x0040;
+        symlink_follow: bool = false,
         /// Path refers to directory
-        pub const REMOVEDIR = 0x0080;
+        removedir: bool = false,
+        _9: u24 = 0,
+
+        pub const fdcwd: fd_t = -2;
+
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = @bitCast(At{ .eaccess = true });
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `symlink_follow`
+        pub const SYMLINK_FOLLOW: u32 = @bitCast(At{ .symlink_follow = true });
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+        /// DEPRECATED: use `fdcwd`
+        pub const FDCWD = fdcwd;
     },
-    .freebsd => struct {
+    .freebsd => packed struct(u32) {
-        /// Magic value that specify the use of the current working directory
+        _: u8 = 0,
-        /// to determine the target of relative file paths in the openat() and
-        /// similar syscalls.
-        pub const FDCWD = -100;
         /// Check access using effective user and group ID
-        pub const EACCESS = 0x0100;
+        eaccess: bool = false,
         /// Do not follow symbolic links
-        pub const SYMLINK_NOFOLLOW = 0x0200;
+        symlink_nofollow: bool = false,
         /// Follow symbolic link
-        pub const SYMLINK_FOLLOW = 0x0400;
+        symlink_follow: bool = false,
         /// Remove directory instead of file
-        pub const REMOVEDIR = 0x0800;
+        removedir: bool = false,
         /// Fail if not under dirfd
-        pub const BENEATH = 0x1000;
+        beneath: bool = false,
-    },
+        _14: u19 = 0,
-    .netbsd => struct {
+
         /// Magic value that specify the use of the current working directory
         /// to determine the target of relative file paths in the openat() and
         /// similar syscalls.
-        pub const FDCWD = -100;
+        pub const fdcwd: fd_t = -100;
+
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = @bitCast(At{ .eaccess = true });
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `symlink_follow`
+        pub const SYMLINK_FOLLOW: u32 = @bitCast(At{ .symlink_follow = true });
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+        /// DEPRECATED: use `beneath`
+        pub const BENEATH: u32 = @bitCast(At{ .beneath = true });
+
+        /// DEPRECATED: use `fdcwd`
+        pub const FDCWD = fdcwd;
+    },
+    .netbsd => packed struct(u32) {
+        _: u8 = 0,
         /// Check access using effective user and group ID
-        pub const EACCESS = 0x0100;
+        eaccess: bool = false,
         /// Do not follow symbolic links
-        pub const SYMLINK_NOFOLLOW = 0x0200;
+        symlink_nofollow: bool = false,
         /// Follow symbolic link
-        pub const SYMLINK_FOLLOW = 0x0400;
+        symlink_follow: bool = false,
         /// Remove directory instead of file
-        pub const REMOVEDIR = 0x0800;
+        removedir: bool = false,
-    },
+        _12: u20 = 0,
-    .dragonfly => struct {
+
-        pub const FDCWD = -328243;
-        pub const SYMLINK_NOFOLLOW = 1;
-        pub const REMOVEDIR = 2;
-        pub const EACCESS = 4;
-        pub const SYMLINK_FOLLOW = 8;
-    },
-    .openbsd => struct {
         /// Magic value that specify the use of the current working directory
         /// to determine the target of relative file paths in the openat() and
         /// similar syscalls.
-        pub const FDCWD = -100;
+        pub const fdcwd: fd_t = -100;
-        /// Check access using effective user and group ID
+
-        pub const EACCESS = 0x01;
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = @bitCast(At{ .eaccess = true });
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `symlink_follow`
+        pub const SYMLINK_FOLLOW: u32 = @bitCast(At{ .symlink_follow = true });
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+
+        /// DEPRECATED: use `fdcwd`
+        pub const FDCWD = fdcwd;
+    },
+    .dragonfly => packed struct(u32) {
         /// Do not follow symbolic links
-        pub const SYMLINK_NOFOLLOW = 0x02;
+        symlink_nofollow: bool = false,
-        /// Follow symbolic link
-        pub const SYMLINK_FOLLOW = 0x04;
         /// Remove directory instead of file
-        pub const REMOVEDIR = 0x08;
+        removedir: bool = false,
+        /// Check access using effective user and group ID
+        eaccess: bool = false,
+        /// Follow symbolic link
+        symlink_follow: bool = false,
+        _: u28 = 0,
+
+        pub const fdcwd: fd_t = -328243;
+
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = @bitCast(At{ .eaccess = true });
+        /// DEPRECATED: use `symlink_follow`
+        pub const SYMLINK_FOLLOW: u32 = @bitCast(At{ .symlink_follow = true });
+
+        /// DEPRECATED: use `fdcwd`
+        pub const FDCWD = fdcwd;
     },
-    .haiku => struct {
+    .openbsd => packed struct(u32) {
-        pub const FDCWD = -1;
+        /// Check access using effective user and group ID
-        pub const SYMLINK_NOFOLLOW = 0x01;
+        eaccess: bool = false,
-        pub const SYMLINK_FOLLOW = 0x02;
+        /// Do not follow symbolic links
-        pub const REMOVEDIR = 0x04;
+        symlink_nofollow: bool = false,
-        pub const EACCESS = 0x08;
+        /// Follow symbolic link
-    },
+        symlink_follow: bool = false,
-    .illumos => struct {
+        /// Remove directory instead of file
+        removedir: bool = false,
+        _: u28 = 0,
+
         /// Magic value that specify the use of the current working directory
         /// to determine the target of relative file paths in the openat() and
         /// similar syscalls.
-        pub const FDCWD: fd_t = @bitCast(@as(u32, 0xffd19553));
+        pub const fdcwd: fd_t = -100;
+
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = @bitCast(At{ .eaccess = true });
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `symlink_follow`
+        pub const SYMLINK_FOLLOW: u32 = @bitCast(At{ .symlink_follow = true });
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+
+        pub const FDCWD = fdcwd;
+    },
+    .haiku => packed struct(u32) {
         /// Do not follow symbolic links
-        pub const SYMLINK_NOFOLLOW = 0x1000;
+        symlink_nofollow: bool = false,
         /// Follow symbolic link
-        pub const SYMLINK_FOLLOW = 0x2000;
+        symlink_follow: bool = false,
         /// Remove directory instead of file
-        pub const REMOVEDIR = 0x1;
+        removedir: bool = false,
-        pub const TRIGGER = 0x2;
         /// Check access using effective user and group ID
-        pub const EACCESS = 0x4;
+        eaccess: bool = false,
+        _: u28 = 0,
+
+        pub const fdcwd: fd_t = -1;
+
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `symlink_follow`
+        pub const SYMLINK_FOLLOW: u32 = @bitCast(At{ .symlink_follow = true });
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = @bitCast(At{ .eaccess = true });
+
+        /// DEPRECATED: use `fdcwd`
+        pub const FDCWD = fdcwd;
     },
-    .emscripten => struct {
+    .illumos => packed struct(u32) {
-        pub const FDCWD = -100;
+        /// Remove directory instead of file
-        pub const SYMLINK_NOFOLLOW = 0x100;
+        removedir: bool = false,
-        pub const REMOVEDIR = 0x200;
+        trigger: bool = false,
-        pub const SYMLINK_FOLLOW = 0x400;
+        /// Check access using effective user and group ID
-        pub const NO_AUTOMOUNT = 0x800;
+        eaccess: bool = false,
-        pub const EMPTY_PATH = 0x1000;
+        _4: u9 = 0,
-        pub const STATX_SYNC_TYPE = 0x6000;
+        /// Do not follow symbolic links
-        pub const STATX_SYNC_AS_STAT = 0x0000;
+        symlink_nofollow: bool = false,
-        pub const STATX_FORCE_SYNC = 0x2000;
+        /// Follow symbolic link
-        pub const STATX_DONT_SYNC = 0x4000;
+        symlink_follow: bool = false,
-        pub const RECURSIVE = 0x8000;
+        _15: u18 = 0,
+
+        /// Magic value that specify the use of the current working directory
+        /// to determine the target of relative file paths in the openat() and
+        /// similar syscalls.
+        pub const fdcwd: fd_t = @bitCast(@as(u32, 0xffd19553));
+
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+        /// DEPRECATED: use `trigger`
+        pub const TRIGGER: u32 = @bitCast(At{ .trigger = true });
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = @bitCast(At{ .eaccess = true });
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `symlink_follow`
+        pub const SYMLINK_FOLLOW: u32 = @bitCast(At{ .symlink_follow = true });
+
+        /// DEPRECATED: use `fdcwd`
+        pub const FDCWD = fdcwd;
     },
-    .wasi => struct {
+    // Match `AT_*` constants in lib/libc/include/wasm-wasi-musl/__header_fcntl.h
-        // Match `AT_*` constants in lib/libc/include/wasm-wasi-musl/__header_fcntl.h
+    .wasi => packed struct(u32) {
-        pub const EACCESS = 0x0;
+        /// Do not follow symbolic links
-        pub const SYMLINK_NOFOLLOW = 0x1;
+        symlink_nofollow: bool = false,
-        pub const SYMLINK_FOLLOW = 0x2;
+        /// Follow symbolic link
-        pub const REMOVEDIR = 0x4;
+        symlink_follow: bool = false,
-        /// When linking libc, we follow their convention and use -2 for current working directory.
+        /// Remove directory instead of file
-        /// However, without libc, Zig does a different convention: it assumes the
+        removedir: bool = false,
-        /// current working directory is the first preopen. This behavior can be
+        _: u29 = 0,
-        /// overridden with a public function called `wasi_cwd` in the root source
+
-        /// file.
+        pub const eaccess: u32 = @bitCast(At{});
-        pub const FDCWD: fd_t = if (builtin.link_libc) -2 else 3;
+
+        /// When linking libc, we follow their convention and use -2 for
+        /// current working directory. However, without libc, Zig does a
+        /// different convention: it assumes the current working directory is
+        /// the first preopen. This behavior can be overridden with a public
+        /// function called `wasi_cwd` in the root source file.
+        pub const fdcwd: fd_t = if (builtin.link_libc) -2 else 3;
+
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `symlink_follow`
+        pub const SYMLINK_FOLLOW: u32 = @bitCast(At{ .symlink_follow = true });
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+        /// DEPRECATED: use `fdcwd`
+        pub const FDCWD = fdcwd;
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = eaccess;
     },
     // https://github.com/SerenityOS/serenity/blob/2808b0376406a40e31293bb3bcb9170374e90506/Kernel/API/POSIX/fcntl.h#L49-L52
-    .serenity => struct {
+    .serenity => packed struct(u32) {
-        pub const FDCWD = -100;
+        _: u8 = 0,
-        pub const SYMLINK_NOFOLLOW = 0x100;
+        /// Do not follow symbolic links
-        pub const REMOVEDIR = 0x200;
+        symlink_nofollow: bool = false,
-        pub const EACCESS = 0x400;
+        /// Remove directory instead of file
+        removedir: bool = false,
+        /// Check access using effective user and group ID
+        eaccess: bool = false,
+        _11: u21 = 0,
+
+        pub const fdcwd: fd_t = -100;
+
+        /// DEPRECATED: use `symlink_nofollow`
+        pub const SYMLINK_NOFOLLOW: u32 = @bitCast(At{ .symlink_nofollow = true });
+        /// DEPRECATED: use `removedir`
+        pub const REMOVEDIR: u32 = @bitCast(At{ .removedir = true });
+        /// DEPRECATED: use `eaccess`
+        pub const EACCESS: u32 = @bitCast(At{ .eaccess = true });
+        /// DEPRECATED: use `fdcwd`
+        pub const FDCWD = fdcwd;
     },
     else => void,
 };
@@ -10485,7 +10624,7 @@ pub extern "c" fn inotify_add_watch(fd: fd_t, pathname: [*:0]const u8, mask: u32
 pub extern "c" fn inotify_rm_watch(fd: fd_t, wd: c_int) c_int;
 
 pub extern "c" fn fstat64(fd: fd_t, buf: *Stat) c_int;
-pub extern "c" fn fstatat64(dirfd: fd_t, noalias path: [*:0]const u8, noalias stat_buf: *Stat, flags: u32) c_int;
+pub extern "c" fn fstatat64(dirfd: fd_t, noalias path: [*:0]const u8, noalias stat_buf: *Stat, flags: At) c_int;
 pub extern "c" fn fallocate64(fd: fd_t, mode: c_int, offset: off_t, len: off_t) c_int;
 pub extern "c" fn fopen64(noalias filename: [*:0]const u8, noalias modes: [*:0]const u8) ?*FILE;
 pub extern "c" fn ftruncate64(fd: c_int, length: off_t) c_int;

lib/std/fs.zig

@@ -187,7 +187,7 @@ pub fn cwd() Dir {
     } else if (native_os == .wasi) {
         return .{ .fd = std.options.wasiCwd() };
     } else {
-        return .{ .fd = posix.AT.fdcwd };
+        return .{ .fd = posix.At.fdcwd };
     }
 }
 

lib/std/fs/Dir.zig

@@ -148,7 +148,7 @@ pub const Iterator = switch (native_os) {
                 const stat_info = posix.fstatat(
                     self.dir.fd,
                     name,
-                    posix.AT.SYMLINK_NOFOLLOW,
+                    .{ .symlink_nofollow = true },
                 ) catch |err| switch (err) {
                     error.NameTooLong => unreachable,
                     error.SymLinkLoop => unreachable,
@@ -1112,7 +1112,7 @@ pub fn deleteFileZ(self: Dir, sub_path_c: [*:0]const u8) DeleteFileError!void {
             // directory, so we need to handle that case specifically and translate the error
             .driverkit, .ios, .maccatalyst, .macos, .tvos, .visionos, .watchos, .freebsd, .netbsd, .dragonfly, .openbsd, .illumos => {
                 // Don't follow symlinks to match unlinkat (which acts on symlinks rather than follows them)
-                const fstat = posix.fstatatZ(self.fd, sub_path_c, posix.AT.SYMLINK_NOFOLLOW) catch return e;
+                const fstat = posix.fstatatZ(self.fd, sub_path_c, .{ .symlink_nofollow = true }) catch return e;
                 const is_dir = fstat.mode & posix.S.IFMT == posix.S.IFDIR;
                 return if (is_dir) error.IsDir else e;
             },
@@ -1163,7 +1163,7 @@ pub fn deleteDir(self: Dir, sub_path: []const u8) DeleteDirError!void {
         const sub_path_w = try windows.sliceToPrefixedFileW(self.fd, sub_path);
         return self.deleteDirW(sub_path_w.span());
     } else if (native_os == .wasi and !builtin.link_libc) {
-        posix.unlinkat(self.fd, sub_path, posix.AT.REMOVEDIR) catch |err| switch (err) {
+        posix.unlinkat(self.fd, sub_path, posix.At.REMOVEDIR) catch |err| switch (err) {
             error.IsDir => unreachable, // not possible since we pass AT.REMOVEDIR
             else => |e| return e,
         };
@@ -1175,7 +1175,7 @@ pub fn deleteDir(self: Dir, sub_path: []const u8) DeleteDirError!void {
 
 /// Same as `deleteDir` except the parameter is null-terminated.
 pub fn deleteDirZ(self: Dir, sub_path_c: [*:0]const u8) DeleteDirError!void {
-    posix.unlinkatZ(self.fd, sub_path_c, posix.AT.REMOVEDIR) catch |err| switch (err) {
+    posix.unlinkatZ(self.fd, sub_path_c, posix.At.REMOVEDIR) catch |err| switch (err) {
         error.IsDir => unreachable, // not possible since we pass AT.REMOVEDIR
         else => |e| return e,
     };
@@ -1184,7 +1184,7 @@ pub fn deleteDirZ(self: Dir, sub_path_c: [*:0]const u8) DeleteDirError!void {
 /// Same as `deleteDir` except the parameter is WTF16LE, NT prefixed.
 /// This function is Windows-only.
 pub fn deleteDirW(self: Dir, sub_path_w: []const u16) DeleteDirError!void {
-    posix.unlinkatW(self.fd, sub_path_w, posix.AT.REMOVEDIR) catch |err| switch (err) {
+    posix.unlinkatW(self.fd, sub_path_w, posix.At.REMOVEDIR) catch |err| switch (err) {
         error.IsDir => unreachable, // not possible since we pass AT.REMOVEDIR
         else => |e| return e,
     };

lib/std/os/linux.zig

@@ -1253,7 +1253,7 @@ pub fn rmdir(path: [*:0]const u8) usize {
     if (@hasField(SYS, "rmdir")) {
         return syscall1(.rmdir, @intFromPtr(path));
     } else {
-        return syscall3(.unlinkat, @as(usize, @bitCast(@as(isize, At.fdcwd))), @intFromPtr(path), @as(u32, @bitCast(At{ .removedir_or_handle_fid = .{ .removedir = true } })));
+        return syscall3(.unlinkat, @as(usize, @bitCast(@as(isize, At.fdcwd))), @intFromPtr(path), @as(u32, @bitCast(At{ .removedir = true })));
     }
 }
 
@@ -3573,7 +3573,7 @@ pub const STDERR_FILENO = 2;
 pub const AT = At;
 /// matches AT_* and AT_STATX_*
 pub const At = packed struct(u32) {
-    _u1: u8 = 0,
+    _1: u8 = 0,
     /// Do not follow symbolic links
     symlink_nofollow: bool = false,
     /// Remove directory instead of unlinking file

lib/std/posix.zig

@@ -63,7 +63,9 @@ pub const AF = system.AF;
 pub const AF_SUN = system.AF_SUN;
 pub const AI = system.AI;
 pub const ARCH = system.ARCH;
-pub const AT = system.AT;
+/// DEPRECATED: use `At`
+pub const AT = At;
+pub const At = system.At;
 pub const AT_SUN = system.AT_SUN;
 pub const CLOCK = system.CLOCK;
 pub const CPU_COUNT = system.CPU_COUNT;
@@ -480,7 +482,7 @@ fn fchmodat2(dirfd: fd_t, path: []const u8, mode: mode_t, flags: u32) FChmodAtEr
     }
     defer close(pathfd);
 
-    const stat = fstatatZ(pathfd, "", AT.EMPTY_PATH) catch |err| switch (err) {
+    const stat = fstatatZ(pathfd, "", .{ .empty_path = true }) catch |err| switch (err) {
         error.NameTooLong => unreachable,
         error.FileNotFound => unreachable,
         error.Streaming => unreachable,
@@ -1553,7 +1555,7 @@ pub fn open(file_path: []const u8, flags: O, perm: mode_t) OpenError!fd_t {
     if (native_os == .windows) {
         @compileError("Windows does not support POSIX; use Windows-specific API or cross-platform std.fs API");
     } else if (native_os == .wasi and !builtin.link_libc) {
-        return openat(AT.FDCWD, file_path, flags, perm);
+        return openat(At.fdcwd, file_path, flags, perm);
     }
     const file_path_c = try toPosixPath(file_path);
     return openZ(&file_path_c, flags, perm);
@@ -1943,7 +1945,7 @@ pub fn symlink(target_path: []const u8, sym_link_path: []const u8) SymLinkError!
     if (native_os == .windows) {
         @compileError("symlink is not supported on Windows; use std.os.windows.CreateSymbolicLink instead");
     } else if (native_os == .wasi and !builtin.link_libc) {
-        return symlinkat(target_path, AT.FDCWD, sym_link_path);
+        return symlinkat(target_path, At.fdcwd, sym_link_path);
     }
     const target_path_c = try toPosixPath(target_path);
     const sym_link_path_c = try toPosixPath(sym_link_path);
@@ -2103,7 +2105,7 @@ pub fn linkZ(oldpath: [*:0]const u8, newpath: [*:0]const u8) LinkError!void {
 /// On other platforms, both paths are an opaque sequence of bytes with no particular encoding.
 pub fn link(oldpath: []const u8, newpath: []const u8) LinkError!void {
     if (native_os == .wasi and !builtin.link_libc) {
-        return linkat(AT.FDCWD, oldpath, AT.FDCWD, newpath, 0) catch |err| switch (err) {
+        return linkat(At.fdcwd, oldpath, At.fdcwd, newpath, 0) catch |err| switch (err) {
             error.NotDir => unreachable, // link() does not support directories
             else => |e| return e,
         };
@@ -2163,7 +2165,7 @@ pub fn linkat(
         const old: RelativePathWasi = .{ .dir_fd = olddir, .relative_path = oldpath };
         const new: RelativePathWasi = .{ .dir_fd = newdir, .relative_path = newpath };
         const old_flags: wasi.lookupflags_t = .{
-            .SYMLINK_FOLLOW = (flags & AT.SYMLINK_FOLLOW) != 0,
+            .SYMLINK_FOLLOW = (flags & At.SYMLINK_FOLLOW) != 0,
         };
         switch (wasi.path_link(
             old.dir_fd,
@@ -2234,7 +2236,7 @@ pub const UnlinkError = error{
 /// See also `unlinkZ`.
 pub fn unlink(file_path: []const u8) UnlinkError!void {
     if (native_os == .wasi and !builtin.link_libc) {
-        return unlinkat(AT.FDCWD, file_path, 0) catch |err| switch (err) {
+        return unlinkat(At.fdcwd, file_path, 0) catch |err| switch (err) {
             error.DirNotEmpty => unreachable, // only occurs when targeting directories
             else => |e| return e,
         };
@@ -2308,7 +2310,7 @@ pub fn unlinkat(dirfd: fd_t, file_path: []const u8, flags: u32) UnlinkatError!vo
 /// WASI-only. Same as `unlinkat` but targeting WASI.
 /// See also `unlinkat`.
 pub fn unlinkatWasi(dirfd: fd_t, file_path: []const u8, flags: u32) UnlinkatError!void {
-    const remove_dir = (flags & AT.REMOVEDIR) != 0;
+    const remove_dir = (flags & At.REMOVEDIR) != 0;
     const res = if (remove_dir)
         wasi.path_remove_directory(dirfd, file_path.ptr, file_path.len)
     else
@@ -2373,7 +2375,7 @@ pub fn unlinkatZ(dirfd: fd_t, file_path_c: [*:0]const u8, flags: u32) UnlinkatEr
 
 /// Same as `unlinkat` but `sub_path_w` is WTF16LE, NT prefixed. Windows only.
 pub fn unlinkatW(dirfd: fd_t, sub_path_w: []const u16, flags: u32) UnlinkatError!void {
-    const remove_dir = (flags & AT.REMOVEDIR) != 0;
+    const remove_dir = (flags & At.REMOVEDIR) != 0;
     return windows.DeleteFile(sub_path_w, .{ .dir = dirfd, .remove_dir = remove_dir });
 }
 
@@ -2421,7 +2423,7 @@ pub const RenameError = error{
 /// On other platforms, both paths are an opaque sequence of bytes with no particular encoding.
 pub fn rename(old_path: []const u8, new_path: []const u8) RenameError!void {
     if (native_os == .wasi and !builtin.link_libc) {
-        return renameat(AT.FDCWD, old_path, AT.FDCWD, new_path);
+        return renameat(At.fdcwd, old_path, At.FDCWD, new_path);
     } else if (native_os == .windows) {
         const old_path_w = try windows.sliceToPrefixedFileW(null, old_path);
         const new_path_w = try windows.sliceToPrefixedFileW(null, new_path);
@@ -2747,7 +2749,7 @@ pub const MakeDirError = std.Io.Dir.MakeError;
 /// On other platforms, `dir_path` is an opaque sequence of bytes with no particular encoding.
 pub fn mkdir(dir_path: []const u8, mode: mode_t) MakeDirError!void {
     if (native_os == .wasi and !builtin.link_libc) {
-        return mkdirat(AT.FDCWD, dir_path, mode);
+        return mkdirat(At.fdcwd, dir_path, mode);
     } else if (native_os == .windows) {
         const dir_path_w = try windows.sliceToPrefixedFileW(null, dir_path);
         return mkdirW(dir_path_w.span(), mode);
@@ -2832,7 +2834,7 @@ pub const DeleteDirError = error{
 /// On other platforms, `dir_path` is an opaque sequence of bytes with no particular encoding.
 pub fn rmdir(dir_path: []const u8) DeleteDirError!void {
     if (native_os == .wasi and !builtin.link_libc) {
-        return unlinkat(AT.FDCWD, dir_path, AT.REMOVEDIR) catch |err| switch (err) {
+        return unlinkat(At.fdcwd, dir_path, At.REMOVEDIR) catch |err| switch (err) {
             error.FileSystem => unreachable, // only occurs when targeting files
             error.IsDir => unreachable, // only occurs when targeting files
             else => |e| return e,
@@ -2959,7 +2961,7 @@ pub const FchdirError = error{
 } || UnexpectedError;
 
 pub fn fchdir(dirfd: fd_t) FchdirError!void {
-    if (dirfd == AT.FDCWD) return;
+    if (dirfd == At.fdcwd) return;
     while (true) {
         switch (errno(system.fchdir(dirfd))) {
             .SUCCESS => return,
@@ -3012,7 +3014,7 @@ pub const ReadLinkError = error{
 /// On other platforms, the result is an opaque sequence of bytes with no particular encoding.
 pub fn readlink(file_path: []const u8, out_buffer: []u8) ReadLinkError![]u8 {
     if (native_os == .wasi and !builtin.link_libc) {
-        return readlinkat(AT.FDCWD, file_path, out_buffer);
+        return readlinkat(At.fdcwd, file_path, out_buffer);
     } else if (native_os == .windows) {
         var file_path_w = try windows.sliceToPrefixedFileW(null, file_path);
         const result_w = try readlinkW(file_path_w.span(), &file_path_w.data);
@@ -3972,7 +3974,7 @@ pub const FStatAtError = FStatError || error{
 /// On WASI, `pathname` should be encoded as valid UTF-8.
 /// On other platforms, `pathname` is an opaque sequence of bytes with no particular encoding.
 /// See also `fstatatZ`.
-pub fn fstatat(dirfd: fd_t, pathname: []const u8, flags: u32) FStatAtError!Stat {
+pub fn fstatat(dirfd: fd_t, pathname: []const u8, flags: At) FStatAtError!Stat {
     if (native_os == .wasi and !builtin.link_libc) {
         @compileError("use std.Io instead");
     } else if (native_os == .windows) {
@@ -3985,7 +3987,7 @@ pub fn fstatat(dirfd: fd_t, pathname: []const u8, flags: u32) FStatAtError!Stat
 
 /// Same as `fstatat` but `pathname` is null-terminated.
 /// See also `fstatat`.
-pub fn fstatatZ(dirfd: fd_t, pathname: [*:0]const u8, flags: u32) FStatAtError!Stat {
+pub fn fstatatZ(dirfd: fd_t, pathname: [*:0]const u8, flags: At) FStatAtError!Stat {
     if (native_os == .wasi and !builtin.link_libc) {
         @compileError("use std.Io instead");
     }

lib/std/posix/test.zig

@@ -37,7 +37,7 @@ test "check WASI CWD" {
 
         if (!builtin.link_libc) {
             // WASI without-libc hardcodes fd 3 as the FDCWD token so it can be passed directly to WASI calls
-            try expectEqual(3, posix.AT.FDCWD);
+            try expectEqual(3, posix.At.fdcwd);
         }
     }
 }
@@ -907,7 +907,7 @@ test "pwrite with empty buffer" {
 }
 
 fn expectMode(dir: posix.fd_t, file: []const u8, mode: posix.mode_t) !void {
-    const st = try posix.fstatat(dir, file, posix.AT.SYMLINK_NOFOLLOW);
+    const st = try posix.fstatat(dir, file, .{ .symlink_nofollow = true });
     try expectEqual(mode, st.mode & 0b111_111_111);
 }
 
@@ -932,13 +932,13 @@ test "fchmodat smoke test" {
 
     try posix.symlinkat("regfile", tmp.dir.fd, "symlink");
     const sym_mode = blk: {
-        const st = try posix.fstatat(tmp.dir.fd, "symlink", posix.AT.SYMLINK_NOFOLLOW);
+        const st = try posix.fstatat(tmp.dir.fd, "symlink", .{ .symlink_nofollow = true });
         break :blk st.mode & 0b111_111_111;
     };
 
     try posix.fchmodat(tmp.dir.fd, "regfile", 0o640, 0);
     try expectMode(tmp.dir.fd, "regfile", 0o640);
-    try posix.fchmodat(tmp.dir.fd, "regfile", 0o600, posix.AT.SYMLINK_NOFOLLOW);
+    try posix.fchmodat(tmp.dir.fd, "regfile", 0o600, posix.At.SYMLINK_NOFOLLOW);
     try expectMode(tmp.dir.fd, "regfile", 0o600);
 
     try posix.fchmodat(tmp.dir.fd, "symlink", 0o640, 0);
@@ -946,7 +946,7 @@ test "fchmodat smoke test" {
     try expectMode(tmp.dir.fd, "symlink", sym_mode);
 
     var test_link = true;
-    posix.fchmodat(tmp.dir.fd, "symlink", 0o600, posix.AT.SYMLINK_NOFOLLOW) catch |err| switch (err) {
+    posix.fchmodat(tmp.dir.fd, "symlink", 0o600, posix.At.SYMLINK_NOFOLLOW) catch |err| switch (err) {
         error.OperationNotSupported => test_link = false,
         else => |e| return e,
     };