2.6.XX中errno.h

#define    EDEADLK        35    /* Resource deadlock would occur */
#define    ENAMETOOLONG    36    /* File name too long */
#define    ENOLCK        37    /* No record locks available */
#define    ENOSYS        38    /* Function not implemented */
#define    ENOTEMPTY    39    /* Directory not empty */
#define    ELOOP        40    /* Too many symbolic links encountered */
#define    EWOULDBLOCK    EAGAIN    /* Operation would block */
#define    ENOMSG        42    /* No message of desired type */
#define    EIDRM        43    /* Identifier removed */
#define    ECHRNG        44    /* Channel number out of range */
#define    EL2NSYNC    45    /* Level 2 not synchronized */
#define    EL3HLT        46    /* Level 3 halted */
#define    EL3RST        47    /* Level 3 reset */
#define    ELNRNG        48    /* Link number out of range */
#define    EUNATCH        49    /* Protocol driver not attached */
#define    ENOCSI        50    /* No CSI structure available */
#define    EL2HLT        51    /* Level 2 halted */
#define    EBADE        52    /* Invalid exchange */
#define    EBADR        53    /* Invalid request descriptor */
#define    EXFULL        54    /* Exchange full */
#define    ENOANO        55    /* No anode */
#define    EBADRQC        56    /* Invalid request code */
#define    EBADSLT        57    /* Invalid slot */

#define    EDEADLOCK    EDEADLK

#define    EBFONT        59    /* Bad font file format */
#define    ENOSTR        60    /* Device not a stream */
#define    ENODATA        61    /* No data available */
#define    ETIME        62    /* Timer expired */
#define    ENOSR        63    /* Out of streams resources */
#define    ENONET        64    /* Machine is not on the network */
#define    ENOPKG        65    /* Package not installed */
#define    EREMOTE        66    /* Object is remote */
#define    ENOLINK        67    /* Link has been severed */
#define    EADV        68    /* Advertise error */
#define    ESRMNT        69    /* Srmount error */
#define    ECOMM        70    /* Communication error on send */
#define    EPROTO        71    /* Protocol error */
#define    EMULTIHOP    72    /* Multihop attempted */
#define    EDOTDOT        73    /* RFS specific error */
#define    EBADMSG        74    /* Not a data message */
#define    EOVERFLOW    75    /* Value too large for defined data type */
#define    ENOTUNIQ    76    /* Name not unique on network */
#define    EBADFD        77    /* File descriptor in bad state */
#define    EREMCHG        78    /* Remote address changed */
#define    ELIBACC        79    /* Can not access a needed shared library */
#define    ELIBBAD        80    /* Accessing a corrupted shared library */
#define    ELIBSCN        81    /* .lib section in a.out corrupted */
#define    ELIBMAX        82    /* Attempting to link in too many shared libraries */
#define    ELIBEXEC    83    /* Cannot exec a shared library directly */
#define    EILSEQ        84    /* Illegal byte sequence */
#define    ERESTART    85    /* Interrupted system call should be restarted */
#define    ESTRPIPE    86    /* Streams pipe error */
#define    EUSERS        87    /* Too many users */
#define    ENOTSOCK    88    /* Socket operation on non-socket */
#define    EDESTADDRREQ    89    /* Destination address required */
#define    EMSGSIZE    90    /* Message too long */
#define    EPROTOTYPE    91    /* Protocol wrong type for socket */
#define    ENOPROTOOPT    92    /* Protocol not available */
#define    EPROTONOSUPPORT    93    /* Protocol not supported */
#define    ESOCKTNOSUPPORT    94    /* Socket type not supported */
#define    EOPNOTSUPP    95    /* Operation not supported on transport endpoint */
#define    EPFNOSUPPORT    96    /* Protocol family not supported */
#define    EAFNOSUPPORT    97    /* Address family not supported by protocol */
#define    EADDRINUSE    98    /* Address already in use */
#define    EADDRNOTAVAIL    99    /* Cannot assign requested address */
#define    ENETDOWN    100    /* Network is down */
#define    ENETUNREACH    101    /* Network is unreachable */
#define    ENETRESET    102    /* Network dropped connection because of reset */
#define    ECONNABORTED    103    /* Software caused connection abort */
#define    ECONNRESET    104    /* Connection reset by peer */
#define    ENOBUFS        105    /* No buffer space available */
#define    EISCONN        106    /* Transport endpoint is already connected */
#define    ENOTCONN    107    /* Transport endpoint is not connected */
#define    ESHUTDOWN    108    /* Cannot send after transport endpoint shutdown */
#define    ETOOMANYREFS    109    /* Too many references: cannot splice */
#define    ETIMEDOUT    110    /* Connection timed out */
#define    ECONNREFUSED    111    /* Connection refused */
#define    EHOSTDOWN    112    /* Host is down */
#define    EHOSTUNREACH    113    /* No route to host */
#define    EALREADY    114    /* Operation already in progress */
#define    EINPROGRESS    115    /* Operation now in progress */
#define    ESTALE        116    /* Stale NFS file handle */
#define    EUCLEAN        117    /* Structure needs cleaning */
#define    ENOTNAM        118    /* Not a XENIX named type file */
#define    ENAVAIL        119    /* No XENIX semaphores available */
#define    EISNAM        120    /* Is a named type file */
#define    EREMOTEIO    121    /* Remote I/O error */
#define    EDQUOT        122    /* Quota exceeded */

#define    ENOMEDIUM    123    /* No medium found */
#define    EMEDIUMTYPE    124    /* Wrong medium type */
#define    ECANCELED    125    /* Operation Canceled */
#define    ENOKEY        126    /* Required key not available */
#define    EKEYEXPIRED    127    /* Key has expired */
#define    EKEYREVOKED    128    /* Key has been revoked */
#define    EKEYREJECTED    129    /* Key was rejected by service */

/* for robust mutexes */
#define    EOWNERDEAD    130    /* Owner died */
#define    ENOTRECOVERABLE    131    /* State not recoverable */

#define ERFKILL        132    /* Operation not possible due to RF-kill */

#endif

用法： printf("errno is %d\n",errno);
查看错误代码errno是调试程序的一个重要方法。当linuc C api函数发生异常时,一般会将errno变量(需include errno.h)赋一个整数值,不同的值表示不同的含义,可以通过查看该值推测出错的原因。在实际编程中用这一招解决了不少原本看来莫名其妙的问题。比较麻烦的是每次都要去linux源代码里面查找错误代码的含义，现在把它贴出来，以后需要查时就来这里看了。