Linux有着完整的错误代号机制，通过<errno.h>中的errno变量，再结合<string.h>中的strerror函数，可以清楚的了解到之前的函数调用的出错原因。

以下是所有错误代码及原因的列表

   124 EMEDIUMTYPE   Wrong medium type

   123 ENOMEDIUM     No medium found

   122 EDQUOT        Disk quota exceeded

   121 EREMOTEIO     Remote I/O error

   120 EISNAM        Is a named type file

   119 ENAVAIL       No XENIX semaphores available

   118 ENOTNAM       Not a XENIX named type file

   117 EUCLEAN       Structure needs cleaning

   116 ESTALE        Stale NFS file handle

   115 EINPROGRESS  +Operation now in progress

   114 EALREADY      Operation already in progress

   113 EHOSTUNREACH  No route to host

   112 EHOSTDOWN     Host is down

   111 ECONNREFUSED  Connection refused

   110 ETIMEDOUT    +Connection timed out

   109 ETOOMANYREFS  Too many references: cannot splice

   108 ESHUTDOWN     Cannot send after transport endpoint shutdown

   107 ENOTCONN      Transport endpoint is not connected

   106 EISCONN       Transport endpoint is already connected

   105 ENOBUFS       No buffer space available

   104 ECONNRESET    Connection reset by peer

   103 ECONNABORTED  Software caused connection abort

   102 ENETRESET     Network dropped connection on reset

   101 ENETUNREACH   Network is unreachable

   100 ENETDOWN      Network is down

    99 EADDRNOTAVAIL Cannot assign requested address

    98 EADDRINUSE    Address already in use

    97 EAFNOSUPPORT  Address family not supported by protocol

    96 EPFNOSUPPORT  Protocol family not supported

    95 EOPNOTSUPP    Operation not supported

    94 ESOCKTNOSUPPORT Socket type not supported

    93 EPROTONOSUPPORT Protocol not supported

    92 ENOPROTOOPT   Protocol not available

    91 EPROTOTYPE    Protocol wrong type for socket

    90 EMSGSIZE     +Message too long

    89 EDESTADDRREQ  Destination address required

    88 ENOTSOCK      Socket operation on non-socket

    87 EUSERS        Too many users

    86 ESTRPIPE      Streams pipe error

    85 ERESTART      Interrupted system call should be restarted

    84 EILSEQ        Invalid or incomplete multibyte or wide character

    83 ELIBEXEC      Cannot exec a shared library directly

    82 ELIBMAX       Attempting to link in too many shared libraries

    81 ELIBSCN       .lib section in a.out corrupted

    80 ELIBBAD       Accessing a corrupted shared library

    79 ELIBACC       Can not access a needed shared library

    78 EREMCHG       Remote address changed

    77 EBADFD        File descriptor in bad state

    76 ENOTUNIQ      Name not unique on network

    75 EOVERFLOW     Value too large for defined data type

    74 EBADMSG      +Bad message

    73 EDOTDOT       RFS specific error

    72 EMULTIHOP     Multihop attempted

    71 EPROTO        Protocol error

    70 ECOMM         Communication error on send

    69 ESRMNT        Srmount error

    68 EADV          Advertise error

    67 ENOLINK       Link has been severed

    66 EREMOTE       Object is remote

    65 ENOPKG        Package not installed

    64 ENONET        Machine is not on the network

    63 ENOSR         Out of streams resources

    62 ETIME         Timer expired

    61 ENODATA       No data available

    60 ENOSTR        Device not a stream

    59 EBFONT        Bad font file format

    57 EBADSLT       Invalid slot

    56 EBADRQC       Invalid request code

    55 ENOANO        No anode

    54 EXFULL        Exchange full

    53 EBADR         Invalid request descriptor

    52 EBADE         Invalid exchange

    51 EL2HLT        Level 2 halted

    50 ENOCSI        No CSI structure available

    49 EUNATCH       Protocol driver not attached

    48 ELNRNG        Link number out of range

    47 EL3RST        Level 3 reset

    46 EL3HLT        Level 3 halted

    45 EL2NSYNC      Level 2 not synchronized

    44 ECHRNG        Channel number out of range

    43 EIDRM         Identifier removed

    42 ENOMSG        No message of desired type

    40 ELOOP         Too many levels of symbolic links

    39 ENOTEMPTY    +Directory not empty

    38 ENOSYS       +Function not implemented

    37 ENOLCK       +No locks available

    36 ENAMETOOLONG +File name too long

    35 EDEADLK      +Resource deadlock avoided

    34 ERANGE       +Numerical result out of range

    33 EDOM         +Numerical argument out of domain

    32 EPIPE        +Broken pipe

    31 EMLINK       +Too many links

    30 EROFS        +Read-only file system

    29 ESPIPE       +Illegal seek

    28 ENOSPC       +No space left on device

    27 EFBIG        +File too large

    26 ETXTBSY       Text file busy

    25 ENOTTY       +Inappropriate ioctl for device

    24 EMFILE       +Too many open files

    23 ENFILE       +Too many open files in system

    22 EINVAL       +Invalid argument

    21 EISDIR       +Is a directory

    20 ENOTDIR      +Not a directory

    19 ENODEV       +No such device

    18 EXDEV        +Invalid cross-device link

    17 EEXIST       +File exists

    16 EBUSY        +Device or resource busy

    15 ENOTBLK       Block device required

    14 EFAULT       +Bad address

    13 EACCES       +Permission denied

    12 ENOMEM       +Cannot allocate memory

    11 EAGAIN       +Resource temporarily unavailable

    10 ECHILD       +No child processes

     9 EBADF        +Bad file descriptor

     8 ENOEXEC      +Exec format error

     7 E2BIG        +Argument list too long

     6 ENXIO        +No such device or address

     5 EIO          +Input/output error

     4 EINTR        +Interrupted system call

     3 ESRCH        +No such process

     2 ENOENT       +No such file or directory

     1 EPERM        +Operation not permitted

     0 --            Success

 

source from: http://blog.csdn.net/wei801004/archive/2009/06/08/4252370.aspx