strerror(errno)：获取errno对应的错误 查看错误代码errno是调试程序的一个重要方法。当linux 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。 errno.00 is: Success errno.01 is: Operation not permitted errno.02 is: No such file or directory errno.03 is: No such process errno.04 is: Interrupted system call errno.05 is: Input/output error errno.06 is: No such device or address errno.07 is: Argument list too long errno.08 is: Exec format error errno.09 is: Bad file descriptor errno.10 is: No child processes errno.11 is: Resource temporarily unavailable[资源临时不可用](连续发送数据时候回出此错，加延时) errno.12 is: Cannot allocate memory errno.13 is: Permission denied errno.14 is: Bad address errno.15 is: Block device required errno.16 is: Device or resource busy errno.17 is: File exists errno.18 is: Invalid cross-device link errno.19 is: No such device errno.20 is: Not a directory errno.21 is: Is a directory errno.22 is: Invalid argument errno.23 is: Too many open files in system errno.24 is: Too many open files errno.25 is: Inappropriate ioctl for device errno.26 is: Text file busy errno.27 is: File too large errno.28 is: No space left on device errno.29 is: Illegal seek errno.30 is: Read-only file system errno.31 is: Too many links errno.32 is: Broken pipe[断开的管道](原因：the broken pipe error occurs if one end of the TCP socket closes connection(using disconnect) or gets killed and the other end tries to still write to it. An indication of a closed/terminated connection is a return value of 0 when you try to read from that socket using recv. After receiving such an error, if you try to still write to the socket, your process gets sent the SIGPIPE signal which kills it. ) errno.33 is: Numerical argument out of domain errno.34 is: Numerical result out of range errno.35 is: Resource deadlock avoided errno.36 is: File name too long errno.37 is: No locks available errno.38 is: Function not implemented errno.39 is: Directory not empty errno.40 is: Too many levels of symbolic links errno.41 is: Unknown error 41 errno.42 is: No message of desired type errno.43 is: Identifier removed errno.44 is: Channel number out of range errno.45 is: Level 2 not synchronized errno.46 is: Level 3 halted errno.47 is: Level 3 reset errno.48 is: Link number out of range errno.49 is: Protocol driver not attached errno.50 is: No CSI structure available errno.51 is: Level 2 halted errno.52 is: Invalid exchange errno.53 is: Invalid request descriptor errno.54 is: Exchange full errno.55 is: No anode errno.56 is: Invalid request code errno.57 is: Invalid slot errno.58 is: Unknown error 58 errno.59 is: Bad font file format errno.60 is: Device not a stream errno.61 is: No data available errno.62 is: Timer expired errno.63 is: Out of streams resources errno.64 is: Machine is not on the network errno.65 is: Package not installed errno.66 is: Object is remote errno.67 is: Link has been severed errno.68 is: Advertise error errno.69 is: Srmount error errno.70 is: Communication error on send errno.71 is: Protocol error errno.72 is: Multihop attempted errno.73 is: RFS specific error errno.74 is: Bad message errno.75 is: Value too large for defined data type errno.76 is: Name not unique on network errno.77 is: File descriptor in bad state errno.78 is: Remote address changed errno.79 is: Can not access a needed shared library errno.80 is: Accessing a corrupted shared library errno.81 is: .lib section in a.out corrupted errno.82 is: Attempting to link in too many shared libraries errno.83 is: Cannot exec a shared library directly errno.84 is: Invalid or incomplete multibyte or wide character errno.85 is: Interrupted system call should be restarted errno.86 is: Streams pipe error errno.87 is: Too many users errno.88 is: Socket operation on non-socket errno.89 is: Destination address required errno.90 is: Message too long errno.91 is: Protocol wrong type for socket errno.92 is: Protocol not available errno.93 is: Protocol not supported errno.94 is: Socket type not supported errno.95 is: Operation not supported errno.96 is: Protocol family not supported errno.97 is: Address family not supported by protocol errno.98 is: Address already in use errno.99 is: Cannot assign requested address errno.100 is: Network is down errno.101 is: Network is unreachable errno.102 is: Network dropped connection on reset errno.103 is: Software caused connection abort errno.104 is: Connection reset by peer[l连接被对端重置] errno.105 is: No buffer space available errno.106 is: Transport endpoint is already connected errno.107 is: Transport endpoint is not connected errno.108 is: Cannot send after transport endpoint shutdown errno.109 is: Too many references: cannot splice errno.110 is: Connection timed out errno.111 is: Connection refused errno.112 is: Host is down errno.113 is: No route to host errno.114 is: Operation already in progress errno.115 is: Operation now in progress errno.116 is: Stale NFS file handle errno.117 is: Structure needs cleaning errno.118 is: Not a XENIX named type file errno.119 is: No XENIX semaphores available errno.120 is: Is a named type file errno.121 is: Remote I/O error errno.122 is: Disk quota exceeded errno.123 is: No medium found errno.124 is: Wrong medium type errno.125 is: Operation canceled errno.126 is: Required key not available errno.127 is: Key has expired errno.128 is: Key has been revoked errno.129 is: Key was rejected by service errno.130 is: Owner died errno.131 is: State not recoverable errno.132 is: Unknown error 132 132-255 全是Unknown error