linux中错误编号对应意思
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。
以下来自linux 2.4.20-18的内核代码中的/usr/include/asm/errno.h
#ifndef _I386_ERRNO_H
#define _I386_ERRNO_H
#define EPERM   1 /* Operation not permitted */
#define ENOENT   2 /* No such file or directory */
#define ESRCH   3 /* No such process */
#define EINTR   4 /* Interrupted system call */
#define EIO       5 /* I/O error */
#define ENXIO   6 /* No such device or address */
#define E2BIG   7 /* Arg list too long */
#define ENOEXEC   8 /* Exec format error */
#define EBADF   9 /* Bad file number */
#define ECHILD  10 /* No child processes */
#define EAGAIN  11 /* Try again */
#define ENOMEM  12 /* Out of memory */
#define EACCES  13 /* Permission denied */
#define EFAULT  14 /* Bad address */
#define ENOTBLK  15 /* Block device required */
#define EBUSY  16 /* Device or resource busy */
#define EEXIST  17 /* File exists */
#define EXDEV  18 /* Cross-device link */
#define ENODEV  19 /* No such device */
#define ENOTDIR  20 /* Not a directory */
#define EISDIR  21 /* Is a directory */
#define EINVAL  22 /* Invalid argument */
#define ENFILE  23 /* File table overflow */
#define EMFILE  24 /* Too many open files */
#define ENOTTY  25 /* Not a typewriter */
#define ETXTBSY  26 /* Text file busy */
#define EFBIG  27 /* File too large */
#define ENOSPC  28 /* No space left on device */
#define ESPIPE  29 /* Illegal seek */
#define EROFS  30 /* Read-only file system */
#define EMLINK  31 /* Too many links */
#define EPIPE  32 /* Broken pipe */
#define EDOM  33 /* Math argument out of domain of func */
#define ERANGE  34 /* Math result not representable */
#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