Linux Error Codes
Linux error codes are those codes that are displayed if an error occurs in the system while working or using a program. The errors can be recognized with the help of error codes. The error codes assist us in recognizing the source of error.
If we are working on a Linux system, it is obvious that we may encounter errors. Some errors can be minor and may not lead to interruption of the program. But there can be some errors that can cause a system or program to stop responding. These errors can lead to loss of data or may prevent the program from completing. Mostly errors are displayed in the form of codes or messages.
In this section, we will see errors in C programming and a list of possible errors in the Linux system.
Linux Errors in C programming
A skilled programmer should know how to deal with the errors. C programming language does not provide direct support for error handling. We have to detect the source of the error and deal with it. In C language, the return values display the failure or success. If a function in the C program fails, we must handle the error accordingly; otherwise it records the errors last in a log file.
While executing the C programs, we might notice some error numbers such as “Error no is: 17”. Here, the error no 17 means the file already exists. Every error number has some meaning.
The C language supports a variable ‘errorno.’ By using this error number variable, we can use some error handling functions to handle it properly.
To use the external variable error number, we have to include a header file ‘errno.h.’ The <error.h> header file is used to define the ‘errno’ variable. The errno variable is set by the system calls and library functions in the error occurrence. There are two important functions in the C programming language to deal with errors; perror and strerror. The perror function is used to print the error description and the sterror function returns a string having error code.
Let’s display the list of error codes by using errno.
Linux errno
The errno utility is used to looks up errno codes, macro names, and the corresponding descriptions. For example, if we provide ENOENT on a Linux system, it will display the code 2 and description ” No such file or directory.” If we provide the code 2, then it will display the ENOENT and its description.
If errno utility is not installed on our machine, it will display the error as follows:
To install it, execute the below command:
By executing the above command, the moreutils package is installed on our machine that contains the errno utility.
Display the List of Error codes
To display the list of the error codes, execute the command as follows:
The above command will display the list of error codes by RedHat. Consider the below output:
Display the information of an error number
To display the information of a particular error number, execute the command as follows:
The above command will display the description of error number 2. Consider the below output:
Display the information of an error name
To display the information of a particular error name, execute the errno command, followed by the error name. For example, to display the information of an error name ‘ESRCH,’ execute the command as follows:
The above command will display the information about the specified error name. Consider the below output:
Display the error using strings
To display an error description by using a string from the description, execute the command as follows:
The above command will display the errors whose description contains string permission. Consider the below output:
List of Linux system Errors
Following is a partial list of possible errors of Linux system:
| Error code | Error no | Description |
|---|---|---|
| EPERM | 1 | It is displayed if the operation is not permitted. |
| ENOENT | 2 | It is displayed if there is no such file or directory exists. |
| ESRCH | 3 | It is displayed if there is no such process exists. |
| EINTR | 4 | It is displayed for Interrupted system call |
| EIO | 5 | It is displayed for input/output error. |
| ENXIO | 6 | It is displayed if there is no such device or address exists. |
| E2BIG | 7 | It is displayed if argument list is too long. |
| ENOEXEC | 8 | It is displayed if there is an exec format error |
| EBADF | 9 | It is displayed in case of bad file descriptor. |
| ECHILD | 10 | It is displayed if there is no child process exists. |
| EAGAIN | 11 | It is displayed if resource is temporarily unavailable. |
| ENOMEM | 12 | It is displayed if the system cannot allocate memory. |
| EACCES | 13 | It is displayed if permission is denied. |
| EFAULT | 14 | It is displayed if there is a bad address. |
| ENOTBLK | 15 | It is displayed if Block device is required. |
| EBUSY | 16 | It is displayed if device or resource is busy. |
| EEXIST | 17 | It is displayed if file already exists. |
| EXDEV | 18 | It is displayed if there is invalid cross-device link. |
| ENODEV | 19 | It is displayed if there is no such device. |
| ENOTDIR | 20 | It is displayed if there is not a directory. |
| EISDIR | 21 | It is displayed if there is a directory. |
| EINVAL | 22 | It is displayed if there is an invalid argument. |
| ENFILE | 23 | It is displayed if there are too many open files in system. |
| EMFILE | 24 | It is displayed if there are too many open files. |
| ENOTTY | 25 | It is displayed if there is an inappropriate ioctl for device. |
| ETXTBSY | 26 | It is displayed if text file is busy. |
| EFBIG | 27 | It is displayed if the file is too large. |
| ENOSPC | 28 | It is displayed if there is no space left on device. |
| ESPIPE | 29 | It is displayed in case of illegal seek. |
| EROFS | 30 | It is displayed in case of read-only file system. |
| EMLINK | 31 | It is displayed if there are too many links. |
| EPIPE | 32 | It is displayed in case of broken pipe. |
| EDOM | 33 | It is displayed if numerical argument is out of domain. |
| ERANGE | 34 | It is displayed if numerical result is out of range. |
| EDEADLK | 35 | It is displayed if resource deadlock is avoided. |
| ENAMETOOLONG | 36 | It is displayed if file name is too long. |
| ENOLCK | 37 | It is displayed if no locks are available. |
| ENOSYS | 38 | It is displayed if function is not implemented. |
| ENOTEMPTY | 39 | It is displayed if directory is not empty. |
| ELOOP | 40 | It is displayed if there are too many levels of symbolic links. |
| ENOMSG | 42 | It is displayed if there is no message of desired type. |
| EIDRM | 43 | It is displayed if identifier is removed. |
| ECHRNG | 44 | It is displayed if channel number is out of range. |
| EL2NSYNC | 45 | It is displayed if level 2 is not synchronized. |
| EL3HLT | 46 | It is displayed if Level 3 is halted. |
| EL3RST | 47 | It is displayed if Level 3 is reset. |
| ELNRNG | 48 | It is displayed if the link number is out of range. |
| EUNATCH | 49 | It is displayed if protocol driver is not attached. |
| ENOCSI | 50 | It is displayed if there is no CSI structure available. |
| EL2HLT | 51 | It is displayed if Level 2 is halted. |
| EBADE | 52 | It is displayed in case of invalid exchange. |
| EBADR | 53 | It is displayed in case of invalid request descriptor. |
| EXFULL | 54 | It is displayed if exchange is full. |
| ENOANO | 55 | It is displayed in case of No anode. |
| EBADRQC | 56 | It is displayed for invalid request code. |
| EBADSLT | 57 | It is displayed for invalid slot. |
| EBFONT | 59 | It is displayed if there is bad font file format. |
| ENOSTR | 60 | It is displayed if device is not a stream. |
| ENODATA | 61 | It is displayed if there is no data available. |
| ETIME | 62 | It is displayed in case of timer is expired. |
| ENOSR | 63 | It is displayed in case of out of streams resources. |
| ENONET | 64 | It is displayed if machine is not on the network. |
| ENOPKG | 65 | It is displayed if package is not installed. |
| EREMOTE | 66 | It is displayed if object is remote. |
| ENOLINK | 67 | It is displayed if the link has been severed. |
| EADV | 68 | It is displayed for advertise error. |
| ESRMNT | 69 | It is displayed for Srmount error. |
| ECOMM | 70 | It is displayed if there is communication error on send. |
| EPROTO | 71 | It is displayed for protocol error. |
| EMULTIHOP | 72 | It is displayed for Multihop attempted. |
| EDOTDOT | 73 | It is displayed for RFS specific error. |
| EBADMSG | 74 | It is displayed for Bad message. |
| EOVERFLOW | 75 | It is displayed if value is too large for defined data type. |
| ENOTUNIQ | 76 | It is displayed if name is not unique on network. |
| EBADFD | 77 | It is displayed if file descriptor is in bad state. |
| EREMCHG | 78 | It is displayed if remote address is changed. |
| ELIBACC | 79 | It is displayed if we cannot access a needed shared library. |
| ELIBBAD | 80 | It is displayed in case of accessing a corrupted shared library. |
| ELIBSCN | 81 | It is displayed if there is .lib section in a.out is corrupted. |
| ELIBMAX | 82 | It is displayed if we are attempting to link in too many shared libraries. |
| ELIBEXEC | 83 | It is displayed if we cannot exec a shared library directly. |
| EILSEQ | 84 | It is displayed for an invalid or incomplete multibyte or wide character |
| ERESTART | 85 | It is displayed to inform that interrupted system call should be restarted. |
| ESTRPIPE | 86 | It is displayed if there is streams pipe error. |
| EUSERS | 87 | It is displayed for too many users. |
| ENOTSOCK | 88 | It is displayed for socket operation on non-socket. |
| EDESTADDRREQ | 89 | It is displayed if the destination address is required. |
| EMSGSIZE | 90 | It is displayed if message is too long. |
| EPROTOTYPE | 91 | It is displayed if the protocol is wrong type for socket. |
| ENOPROTOOPT | 92 | It is displayed if the protocol is not available. |
| EPROTONOSUPPORT | 93 | It is displayed if protocol is not supported. |
| ESOCKTNOSUPPORT | 94 | It is displayed if the Socket type is not supported. |
| EOPNOTSUPP | 95 | It is displayed if the Operation is not supported. |
| EPFNOSUPPORT | 96 | It is displayed if the protocol family is not supported. |
| EAFNOSUPPORT | 97 | It is displayed if the address family is not supported by protocol. |
| EADDRINUSE | 98 | It is displayed if the address is already in use. |
| EADDRNOTAVAIL | 99 | It is displayed if the system cannot assign requested address. |
| ENETDOWN | 100 | It is displayed if network is down. |
| ENETUNREACH | 101 | It is displayed if network is unreachable. |
| ENETRESET | 102 | It is displayed if network has dropped connection on reset. |
| ECONNABORTED | 103 | It is displayed if software caused connection abort. |
| ECONNRESET | 104 | It is displayed if connection is reset by peer. |
| ENOBUFS | 105 | It is displayed if there is no buffer space available. |
| EISCONN | 106 | It is displayed if the transport endpoint is already connected. |
| ENOTCONN | 107 | It is displayed if the transport endpoint is not connected. |
| ESHUTDOWN | 108 | It is displayed if the system cannot send after transport endpoint shutdown. |
| ETOOMANYREFS | 109 | It is displayed if there are too many references: cannot splice. |
| ETIMEDOUT | 110 | It is displayed if connection is timed out. |
| ECONNREFUSED | 111 | It is displayed if connection is refused. |
| EHOSTDOWN | 112 | It is displayed if the Host is down. |
| EHOSTUNREACH | 113 | It is displayed if there is no route to host. |
| EALREADY | 114 | It is displayed if operation is already in progress. |
| EINPROGRESS | 115 | It is displayed if the operation is now in progress. |
| ESTALE | 116 | It is displayed for Stale file handle. |
| EUCLEAN | 117 | It is displayed if structure needs cleaning. |
| ENOTNAM | 118 | It is displayed for not a XENIX named type file. |
| ENAVAIL | 119 | It is displayed if there are no XENIX semaphores are available. |
| EISNAM | 120 | It is displayed if there is a named type file. |
| EREMOTEIO | 121 | It is displayed for Remote I/O error. |
| EDQUOT | 122 | It is displayed if disk quota is exceeded. |
| ENOMEDIUM | 123 | It is displayed if there is no medium found. |
| EMEDIUMTYPE | 124 | It is displayed if there is wrong medium type. |
| ECANCELED | 125 | It is displayed if operation is cancelled. |
| ENOKEY | 126 | It is displayed if required key is not available. |
| EKEYEXPIRED | 127 | It is displayed if the key has expired. |
| EKEYREVOKED | 128 | It is displayed if the key has been revoked. |
| EKEYREJECTED | 129 | It is displayed if the key was rejected by service. |
| EOWNERDEAD | 130 | It is displayed if the Owner is died. |
| ENOTRECOVERABLE | 131 | It is displayed for no recoverable state. |
| ERFKILL | 132 | It is displayed if the operation is not possible due to RF-kill. |
| EHWPOISON | 133 | It is displayed if the memory page has hardware error. |