pub const E = enum(u16) {
    SUCCESS = 0,
    DOM = 1000,
    RANGE = 1001,
    PLAN9 = 1002,

    @"2BIG" = 1,
    ACCES = 2,
    AGAIN = 3,
    // WOULDBLOCK = 3, // TODO errno.h has 2 names for 3
    BADF = 4,
    BUSY = 5,
    CHILD = 6,
    DEADLK = 7,
    EXIST = 8,
    FAULT = 9,
    FBIG = 10,
    INTR = 11,
    INVAL = 12,
    IO = 13,
    ISDIR = 14,
    MFILE = 15,
    MLINK = 16,
    NAMETOOLONG = 17,
    NFILE = 18,
    NODEV = 19,
    NOENT = 20,
    NOEXEC = 21,
    NOLCK = 22,
    NOMEM = 23,
    NOSPC = 24,
    NOSYS = 25,
    NOTDIR = 26,
    NOTEMPTY = 27,
    NOTTY = 28,
    NXIO = 29,
    PERM = 30,
    PIPE = 31,
    ROFS = 32,
    SPIPE = 33,
    SRCH = 34,
    XDEV = 35,

    // bsd networking software
    NOTSOCK = 36,
    PROTONOSUPPORT = 37,
    // PROTOTYPE = 37, // TODO errno.h has two names for 37
    CONNREFUSED = 38,
    AFNOSUPPORT = 39,
    NOBUFS = 40,
    OPNOTSUPP = 41,
    ADDRINUSE = 42,
    DESTADDRREQ = 43,
    MSGSIZE = 44,
    NOPROTOOPT = 45,
    SOCKTNOSUPPORT = 46,
    PFNOSUPPORT = 47,
    ADDRNOTAVAIL = 48,
    NETDOWN = 49,
    NETUNREACH = 50,
    NETRESET = 51,
    CONNABORTED = 52,
    ISCONN = 53,
    NOTCONN = 54,
    SHUTDOWN = 55,
    TOOMANYREFS = 56,
    TIMEDOUT = 57,
    HOSTDOWN = 58,
    HOSTUNREACH = 59,
    GREG = 60,

    // These added in 1003.1b-1993
    CANCELED = 61,
    INPROGRESS = 62,

    // We just add these to be compatible with std.os, which uses them,
    // They should never get used.
    DQUOT,
    CONNRESET,
    OVERFLOW,
    LOOP,
    TXTBSY,

    pub fn init(r: usize) E {
        const signed_r: isize = @bitCast(r);
        const int = if (signed_r > -4096 and signed_r < 0) -signed_r else 0;
        return @enumFromInt(int);
    }
}