ENOENT表示没有找到文件或目录，EACCES表示权限不足等。在Linux系统中，错误号（Error Codes）通常用于标识系统调用或程序执行过程中发生的错误类型，这些错误号有助于开发者和系统管理员快速定位问题所在，并采取相应的解决措施，本文将详细介绍一些常见的Linux错误号及其含义，并通过表格形式展示部分重要错误码。
常见Linux错误号及含义
| 错误号 | 名称 | 描述 |
| 1 | EPERM | Operation not permitted |
| 2 | ENOENT | No such file or directory |
| 3 | ESRCH | No such process |
| 4 | ENOMEM | Not enough space |
| 5 | EACCES | Permission denied |
| 6 | EFAULT | Bad address |
| 7 | EBUSY | Device or resource busy |
| 8 | EEXISTS | File exists |
| 9 | EXDEV | Improper link |
| 10 | ENOTDIR | Is a directory |
| 11 | EISDIR | Is a regular file |
| 12 | ENOMEM | Out of memory |
| 13 | EACCES | Permission denied |
| 14 | EFAULT | Bad address |
| 15 | EAGAIN | Try again |
| 16 | EINVAL | Invalid argument |
| 17 | ERANGE | Result too large |
| 18 | EINTR | Interrupted system call |
| 19 | EIO | I/O error |
| 20 | ENXIO | No such device or address |
| 21 | E2BIG | Argument list too long |
| 22 | ENOEXEC | Exec format error |
| 23 | EBADF | Bad file number |
| 24 | ECHILD | No child processes |
| 25 | EAGAIN | Try again |
| 26 | ENONET | Machine is not on the network |
| 27 | EADDRINUSE | Address already in use |
| 28 | EADDRNOTAVAIL | Can't assign requested address |
| 29 | ENETDOWN | Network is down |
| 30 | ENETUNREACH | Network is unreachable |
| 31 | ENETRESET | Network dropped connection on reset |
| 32 | ECONNABORTED | Software caused connection abort |
| 33 | ECONNRESET | Connection reset by peer |
| 34 | ENOBUFS | No buffer space available |
| 35 | EAFNOSUPPORT | Address family not supported |
| 36 | EPROTOTYPE | Protocol wrong type for socket |
| 37 | ENOTSOCK | Socket operation on non-socket |
| 38 | EOPNOTSUPP | Operation not supported |
| 39 | EPFNOSUPPORT | Protocol family not supported |
| 40 | ENOTSUP | Operation not supported |
| 41 | ENETRESET | Network dropped connection on reset |
| 42 | EISCONN | Socket is already connected |
| 43 | ENOTCONN | The socket is not connected |
| 44 | ESHUTDOWN | Can't send after socket shutdown |
| 45 | ETOOMANYREFS | Too many references: can't splice |
| 46 | ETIMEDOUT | Connection timed out |
| 47 | ECONNREFUSED | Connection refused |
| 48 | EHOSTDOWN | Host is down |
| 49 | EHOSTUNREACH | No route to host |
| 50 | EALREADY | Operation would block |
| 51 | EINPROGRESS | Operation now in progress |
| 52 | ESTALED | Stale NFS file handle |
| 53 | EUCLEAN | Structure needs cleaning |
| 54 | ENOTNA | Not a directory |
| 55 | ENOANO | Anomalous group file structure |
| 56 | EIOCBQUEUED | I/O control operation already queued |
| 57 | EBADSLT | Invalid slot |
| 58 | ENOSR | Out of streams resources |
| 59 | ELIBACC | Accessing a corrupted shared library |
| 60 | ELIBBAD | .lib section in a.out file has errors |
| 61 | ELIBSCN | .lib section in a.out corrupted |
| 62 | ELIBMAX | Attempting to link in too many libraries |
| 63 | ELIBEXEC | Unable to exec because an alternate version was linked |
| 64 | EILSEQ | Illegal byte sequence |
| 65 | ERESTART | Interrupted system call should be restarted |
| 66 | ESTRPIPE | Stream pipe error |
| 67 | EUSERSRC | Address not available |
| 68 | ENOTSOCK | Operation not permitted |
| 69 | EPROCUBLOCKED | No more processes |
| 70 | ENOSTR | Device not a stream |
| 71 | ENODATA | No data available (for no delay io) |
| 72 | ENOSR | Out of streams resources |
| 73 | ENONET | Machine is not on the network |
| 74 | ENOPKG | Error in package |
| 75 | EREMCHG | Address not available |
| 76 | EIDRM | ID removed |
| 77 | ENOMSG | No message of available |
| 78 | EOVERFLOW | Value too large for defined data type |
| 79 | ENOTUNIQ | Name not unique on the network |
| 80 | EBADFD | Faulty file descriptor |
| 81 | EREMCHG | Address not available |
| 82 | ELIBACC | Can't access shared library |
| 83 | EOWNERDEAD | Previous owner died |
| 84 | ELOOP | Too many symbolic links encountered, or loop |
| 85 | EOPNOTSUPP | Operation not supported |
| ... | ... | ... |
Linux错误号的分类与应用场景
h3. 文件相关错误
这类错误通常与文件操作有关，如打开、关闭、读写文件时出现的问题。
ENOENT: 表示没有找到指定的文件或目录。
EACCES: 表示权限不足，无法访问某个文件或目录。
EBUSY: 表示设备或资源正忙，无法立即完成请求的操作。
h3. 内存相关错误
这些错误涉及到内存分配失败或其他与内存相关的异常情况。
ENOMEM: 表示没有足够的内存空间来完成任务。
EFAULT: 表示访问了无效的地址空间。
EINVAL: 如果参数无效，则可能会返回此错误。
h3. 网络相关错误
网络通信中常见的错误包括连接超时、拒绝连接等。
ETIMEDOUT: 表示尝试建立连接时超时。
ECONNREFUSED: 表示远程主机拒绝了连接请求。
ENETUNREACH: 表示网络不可达。
h3. 进程控制相关错误
涉及进程创建、终止等方面的错误。
EPERM: 表示操作不被允许。
ESRCH: 表示未找到指定的进程。
ECHILD: 表示没有子进程。
Linux错误号处理的最佳实践
1、检查返回值：每次调用可能产生错误的函数后，都应检查其返回值是否为负数，以确定是否有错误发生。
2、使用errno获取具体错误信息：当检测到错误时，可以通过全局变量errno获取更详细的错误描述。
3、适当清理资源：即使遇到错误，也应确保释放已分配的资源，避免内存泄漏等问题。
4、记录日志：对于关键操作失败的情况，应该记录详细的日志信息，便于后续排查问题。
5、合理设计错误处理逻辑：根据不同的错误类型采取相应的恢复措施，比如重试操作、提示用户等。
FAQs
Q1:errno是什么？
A:errno是一个全局变量，用于存储最近一次系统调用失败时的错误代码，它可以帮助程序员了解具体的错误原因。
Q: 如果一个函数返回-1，我该如何判断具体的错误类型？
A: 你可以使用perror()函数打印出详细的错误信息，或者直接查看errno的值来确定具体的错误类型。
Q: 如何避免常见的文件操作错误？
A: 确保文件路径正确无误，检查文件权限设置是否合理，并在进行文件操作前验证文件是否存在，还应该考虑到并发访问的情况，使用适当的锁机制来防止竞态条件。
通过上述内容，相信你对Linux系统下的错误号有了更加清晰的认识，并能在实际工作中更好地应对各种可能出现的错误情况。
以上内容就是解答有关“linux错误号”的详细内容了，我相信这篇文章可以为您解决一些疑惑，有任何问题欢迎留言反馈，谢谢阅读。