Errno {.pure.} = enum
  E_SUCCESS = "success",    ## inner. unstable.
  E2BIG = "Argument list too long", EACCES = "Permission denied",
  EADDRINUSE = "Address already in use",
  EADDRNOTAVAIL = "Cannot assign requested address", EADV = "Advertise error",
  EAFNOSUPPORT = "Address family not supported by protocol",
  EAGAIN = "Resource temporarily unavailable",
  EALREADY = "Operation already in progress", EBADE = "Invalid exchange",
  EBADF = "Bad file descriptor", EBADFD = "File descriptor in bad state",
  EBADMSG = "Bad message", EBADR = "Invalid request descriptor",
  EBADRQC = "Invalid request code", EBADSLT = "Invalid slot",
  EBFONT = "Bad font file format", EBUSY = "Device or resource busy",
  ECANCELED = "Operation canceled", ECHILD = "No child processes",
  ECHRNG = "Channel number out of range", ECOMM = "Communication error on send",
  ECONNABORTED = "Software caused connection abort",
  ECONNREFUSED = "Connection refused", ECONNRESET = "Connection reset by peer",
  EDEADLK = "Resource deadlock avoided",
  EDEADLOCK = "Resource deadlock avoided",
  EDESTADDRREQ = "Destination address required",
  EDOM = "Numerical argument out of domain", EDOTDOT = "RFS specific error",
  EDQUOT = "Disk quota exceeded", EEXIST = "File exists",
  EFAULT = "Bad address", EFBIG = "File too large", EHOSTDOWN = "Host is down",
  EHOSTUNREACH = "No route to host", EIDRM = "Identifier removed",
  EILSEQ = "Invalid or incomplete multibyte or wide character",
  EINPROGRESS = "Operation now in progress", EINTR = "Interrupted system call",
  EINVAL = "Invalid argument", EIO = "Input/output error",
  EISCONN = "Transport endpoint is already connected",
  EISDIR = "Is a directory", EISNAM = "Is a named type file",
  EKEYEXPIRED = "Key has expired", EKEYREJECTED = "Key was rejected by service",
  EKEYREVOKED = "Key has been revoked", EL2HLT = "Level 2 halted",
  EL2NSYNC = "Level 2 not synchronized", EL3HLT = "Level 3 halted",
  EL3RST = "Level 3 reset", ELIBACC = "Can not access a needed shared library",
  ELIBBAD = "Accessing a corrupted shared library",
  ELIBEXEC = "Cannot exec a shared library directly",
  ELIBMAX = "Attempting to link in too many shared libraries",
  ELIBSCN = ".lib section in a.out corrupted",
  ELNRNG = "Link number out of range",
  ELOOP = "Too many levels of symbolic links",
  EMEDIUMTYPE = "Wrong medium type", EMFILE = "Too many open files",
  EMLINK = "Too many links", EMSGSIZE = "Message too long",
  EMULTIHOP = "Multihop attempted", ENAMETOOLONG = "File name too long",
  ENAVAIL = "No XENIX semaphores available", ENETDOWN = "Network is down",
  ENETRESET = "Network dropped connection on reset",
  ENETUNREACH = "Network is unreachable",
  ENFILE = "Too many open files in system", ENOANO = "No anode",
  ENOBUFS = "No buffer space available", ENOCSI = "No CSI structure available",
  ENODATA = "No data available", ENODEV = "No such device",
  ENOENT = "No such file or directory", ENOEXEC = "Exec format error",
  ENOKEY = "Required key not available", ENOLCK = "No locks available",
  ENOLINK = "Link has been severed", ENOMEDIUM = "No medium found",
  ENOMEM = "Cannot allocate memory", ENOMSG = "No message of desired type",
  ENONET = "Machine is not on the network", ENOPKG = "Package not installed",
  ENOPROTOOPT = "Protocol not available", ENOSPC = "No space left on device",
  ENOSR = "Out of streams resources", ENOSTR = "Device not a stream",
  ENOSYS = "Function not implemented", ENOTBLK = "Block device required",
  ENOTCONN = "Transport endpoint is not connected", ENOTDIR = "Not a directory",
  ENOTEMPTY = "Directory not empty", ENOTNAM = "Not a XENIX named type file",
  ENOTRECOVERABLE = "State not recoverable",
  ENOTSOCK = "Socket operation on non-socket",
  ENOTSUP = "Operation not supported",
  ENOTTY = "Inappropriate ioctl for device",
  ENOTUNIQ = "Name not unique on network", ENXIO = "No such device or address",
  EOPNOTSUPP = "Operation not supported",
  EOVERFLOW = "Value too large for defined data type",
  EOWNERDEAD = "Owner died", EPERM = "Operation not permitted",
  EPFNOSUPPORT = "Protocol family not supported", EPIPE = "Broken pipe",
  EPROTO = "Protocol error", EPROTONOSUPPORT = "Protocol not supported",
  EPROTOTYPE = "Protocol wrong type for socket",
  ERANGE = "Numerical result out of range", EREMCHG = "Remote address changed",
  EREMOTE = "Object is remote", EREMOTEIO = "Remote I/O error",
  ERESTART = "Interrupted system call should be restarted",
  ERFKILL = "Operation not possible due to RF-kill",
  EROFS = "Read-only file system",
  ESHUTDOWN = "Cannot send after transport endpoint shutdown",
  ESOCKTNOSUPPORT = "Socket type not supported", ESPIPE = "Illegal seek",
  ESRCH = "No such process", ESRMNT = "Srmount error",
  ESTALE = "Stale file handle", ESTRPIPE = "Streams pipe error",
  ETIME = "Timer expired", ETIMEDOUT = "Connection timed out",
  ETOOMANYREFS = "Too many references: cannot splice",
  ETXTBSY = "Text file busy", EUCLEAN = "Structure needs cleaning",
  EUNATCH = "Protocol driver not attached", EUSERS = "Too many users",
  EWOULDBLOCK = "Resource temporarily unavailable",
  EXDEV = "Invalid cross-device link", EXFULL = "Exchange full"

ErrnoCount = 133