tiny.sys.errno

1const std = @import("std");2const builtin = @import("builtin");3const capabilities = @import("capabilities.zig");45threadlocal var local_errno: c_int = 0;67pub const required_capabilities = capabilities.noLibc(&.{.libc_interop});89pub const StoragePolicy = enum {10    local_thread,11    libc_thread,12};1314const LibcErrno = switch (builtin.os.tag) {15    .linux => switch (builtin.abi) {16        .android, .androideabi => Function("__errno", "c"),17        else => Function("__errno_location", "c"),18    },19    .emscripten, .serenity => Function("__errno_location", "c"),20    .wasi, .dragonfly => ThreadLocal,21    .windows => Function("_errno", "c"),22    .driverkit, .ios, .maccatalyst, .macos, .tvos, .visionos, .watchos, .freebsd => Function("__error", "c"),23    .illumos => Function("___errno", "c"),24    .openbsd, .netbsd => Function("__errno", "c"),25    .haiku => Function("_errnop", "root"),26    else => Local,27};2829pub fn set(value: c_int) void {30    localStorage().* = value;31}3233pub fn current() c_int {34    return localStorage().*;35}3637pub fn setHostInterop(value: c_int) void {38    hostInteropStorage().* = value;39}4041pub fn currentHostInterop() c_int {42    return hostInteropStorage().*;43}4445pub fn storagePolicy() StoragePolicy {46    return .local_thread;47}4849pub fn hostInteropStoragePolicy() StoragePolicy {50    if (comptime builtin.link_libc) return LibcErrno.storage_policy;51    return .local_thread;52}5354fn localStorage() *c_int {55    return &local_errno;56}5758fn hostInteropStorage() *c_int {59    if (comptime builtin.link_libc) return LibcErrno.storage();60    return localStorage();61}6263fn Function(comptime name: []const u8, comptime library_name: ?[]const u8) type {64    return struct {65        const storage_policy: StoragePolicy = .libc_thread;6667        fn storage() *c_int {68            return @extern(*const fn () callconv(.c) *c_int, .{69                .name = name,70                .library_name = library_name,71            })();72        }73    };74}7576const ThreadLocal = struct {77    const storage_policy: StoragePolicy = .libc_thread;7879    extern threadlocal var errno: c_int;8081    fn storage() *c_int {82        return &errno;83    }84};8586const Local = struct {87    const storage_policy: StoragePolicy = .local_thread;8889    fn storage() *c_int {90        return &local_errno;91    }92};9394test "errno access stores nonzero values" {95    set(123);96    try std.testing.expectEqual(@as(c_int, 123), current());97    set(0);98}99100test "errno access is explicit process policy" {101    set(0);102    try std.testing.expectEqual(@as(c_int, 0), current());103    try std.testing.expectEqual(StoragePolicy.local_thread, storagePolicy());104}105106test "errno host interop sharing is explicit" {107    set(0);108    setHostInterop(0);109110    set(77);111    try std.testing.expectEqual(@as(c_int, 77), current());112    if (comptime builtin.link_libc) {113        try std.testing.expectEqual(@as(c_int, 0), currentHostInterop());114    } else {115        try std.testing.expectEqual(@as(c_int, 77), currentHostInterop());116    }117118    setHostInterop(88);119    try std.testing.expectEqual(@as(c_int, 88), currentHostInterop());120    if (comptime builtin.link_libc and LibcErrno.storage_policy == .libc_thread) {121        try std.testing.expectEqual(@as(c_int, 77), current());122    } else {123        try std.testing.expectEqual(@as(c_int, 88), current());124    }125    const expected_policy = if (comptime builtin.link_libc) LibcErrno.storage_policy else StoragePolicy.local_thread;126    try std.testing.expectEqual(expected_policy, hostInteropStoragePolicy());127128    set(0);129    setHostInterop(0);130}

1pub const errno = @import("errno.zig");