"errno" --- 标准 errno 系统符号
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本模块提供标准的 "errno" 系统符号。每个符号的值是其对应的整数值。符号
的名称和描述来自 "linux/include/errno.h"，应该是非常全面的。

errno.errorcode

   提供从 errno 值到底层系统中字符串名称的映射的字典。例如，
   "errno.errorcode[errno.EPERM]" 映射为 "'EPERM'" 。

如果要将数字的错误代码转换为错误信息，请使用 "os.strerror()"。

在下面的列表中，当前平台上没有使用的符号没有被本模块定义。 已定义的符
号的具体列表可参见 "errno.errorcode.keys()"。 可用的符号包括：

errno.EPERM

   Operation not permitted

errno.ENOENT

   No such file or directory

errno.ESRCH

   No such process

errno.EINTR

   Interrupted system call.

   参见: This error is mapped to the exception "InterruptedError".

errno.EIO

   I/O error

errno.ENXIO

   No such device or address

errno.E2BIG

   Arg list too long

errno.ENOEXEC

   Exec format error

errno.EBADF

   Bad file number

errno.ECHILD

   No child processes

errno.EAGAIN

   Try again

errno.ENOMEM

   Out of memory

errno.EACCES

   Permission denied

errno.EFAULT

   Bad address

errno.ENOTBLK

   Block device required

errno.EBUSY

   Device or resource busy

errno.EEXIST

   File exists

errno.EXDEV

   Cross-device link

errno.ENODEV

   No such device

errno.ENOTDIR

   Not a directory

errno.EISDIR

   Is a directory

errno.EINVAL

   Invalid argument

errno.ENFILE

   File table overflow

errno.EMFILE

   Too many open files

errno.ENOTTY

   Not a typewriter

errno.ETXTBSY

   Text file busy

errno.EFBIG

   File too large

errno.ENOSPC

   No space left on device

errno.ESPIPE

   Illegal seek

errno.EROFS

   Read-only file system

errno.EMLINK

   Too many links

errno.EPIPE

   Broken pipe

errno.EDOM

   Math argument out of domain of func

errno.ERANGE

   Math result not representable

errno.EDEADLK

   Resource deadlock would occur

errno.ENAMETOOLONG

   File name too long

errno.ENOLCK

   No record locks available

errno.ENOSYS

   Function not implemented

errno.ENOTEMPTY

   Directory not empty

errno.ELOOP

   Too many symbolic links encountered

errno.EWOULDBLOCK

   Operation would block

errno.ENOMSG

   No message of desired type

errno.EIDRM

   Identifier removed

errno.ECHRNG

   Channel number out of range

errno.EL2NSYNC

   Level 2 not synchronized

errno.EL3HLT

   Level 3 halted

errno.EL3RST

   Level 3 reset

errno.ELNRNG

   Link number out of range

errno.EUNATCH

   Protocol driver not attached

errno.ENOCSI

   No CSI structure available

errno.EL2HLT

   Level 2 halted

errno.EBADE

   Invalid exchange

errno.EBADR

   Invalid request descriptor

errno.EXFULL

   Exchange full

errno.ENOANO

   No anode

errno.EBADRQC

   Invalid request code

errno.EBADSLT

   Invalid slot

errno.EDEADLOCK

   File locking deadlock error

errno.EBFONT

   Bad font file format

errno.ENOSTR

   Device not a stream

errno.ENODATA

   No data available

errno.ETIME

   Timer expired

errno.ENOSR

   Out of streams resources

errno.ENONET

   Machine is not on the network

errno.ENOPKG

   Package not installed

errno.EREMOTE

   Object is remote

errno.ENOLINK

   Link has been severed

errno.EADV

   Advertise error

errno.ESRMNT

   Srmount error

errno.ECOMM

   Communication error on send

errno.EPROTO

   Protocol error

errno.EMULTIHOP

   Multihop attempted

errno.EDOTDOT

   RFS specific error

errno.EBADMSG

   Not a data message

errno.EOVERFLOW

   Value too large for defined data type

errno.ENOTUNIQ

   Name not unique on network

errno.EBADFD

   File descriptor in bad state

errno.EREMCHG

   Remote address changed

errno.ELIBACC

   Can not access a needed shared library

errno.ELIBBAD

   Accessing a corrupted shared library

errno.ELIBSCN

   .lib section in a.out corrupted

errno.ELIBMAX

   Attempting to link in too many shared libraries

errno.ELIBEXEC

   Cannot exec a shared library directly

errno.EILSEQ

   Illegal byte sequence

errno.ERESTART

   Interrupted system call should be restarted

errno.ESTRPIPE

   Streams pipe error

errno.EUSERS

   Too many users

errno.ENOTSOCK

   Socket operation on non-socket

errno.EDESTADDRREQ

   Destination address required

errno.EMSGSIZE

   Message too long

errno.EPROTOTYPE

   Protocol wrong type for socket

errno.ENOPROTOOPT

   Protocol not available

errno.EPROTONOSUPPORT

   Protocol not supported

errno.ESOCKTNOSUPPORT

   Socket type not supported

errno.EOPNOTSUPP

   Operation not supported on transport endpoint

errno.EPFNOSUPPORT

   Protocol family not supported

errno.EAFNOSUPPORT

   Address family not supported by protocol

errno.EADDRINUSE

   Address already in use

errno.EADDRNOTAVAIL

   Cannot assign requested address

errno.ENETDOWN

   Network is down

errno.ENETUNREACH

   Network is unreachable

errno.ENETRESET

   Network dropped connection because of reset

errno.ECONNABORTED

   Software caused connection abort

errno.ECONNRESET

   Connection reset by peer

errno.ENOBUFS

   No buffer space available

errno.EISCONN

   Transport endpoint is already connected

errno.ENOTCONN

   Transport endpoint is not connected

errno.ESHUTDOWN

   Cannot send after transport endpoint shutdown

errno.ETOOMANYREFS

   Too many references: cannot splice

errno.ETIMEDOUT

   Connection timed out

errno.ECONNREFUSED

   Connection refused

errno.EHOSTDOWN

   Host is down

errno.EHOSTUNREACH

   No route to host

errno.EALREADY

   Operation already in progress

errno.EINPROGRESS

   Operation now in progress

errno.ESTALE

   Stale NFS file handle

errno.EUCLEAN

   Structure needs cleaning

errno.ENOTNAM

   Not a XENIX named type file

errno.ENAVAIL

   No XENIX semaphores available

errno.EISNAM

   Is a named type file

errno.EREMOTEIO

   Remote I/O error

errno.EDQUOT

   Quota exceeded
