Linux Error Codes Eagain
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DESCRIPTION top The
Posix Error Codes
is allowed to change errno. Valid error numbers are all nonzero; errno is never set to zero by any system call or library function. For some system calls and library functions (e.g., getpriority(2)), -1 is a valid
Errno.h Linux Kernel
return on success. In such cases, a successful return can be distinguished from an error return by setting errno to zero before the call, and then, if the call returns a status that indicates that an error may have occurred, checking to see if errno has a nonzero value. errno is defined by the ISO C standard to be a modifiable lvalue of type int, and must not be explicitly declared; errno may be a linux errno to string macro. errno is thread-local; setting it in one thread does not affect its value in any other thread. All the error names specified by POSIX.1 must have distinct values, with the exception of EAGAIN and EWOULDBLOCK, which may be the same. Below is a list of the symbolic error names that are defined on Linux. Some of these are marked POSIX.1, indicating that the name is defined by POSIX.1-2001, or C99, indicating that the name is defined by C99. E2BIG Argument list too long (POSIX.1) EACCES Permission denied (POSIX.1) EADDRINUSE Address already in use (POSIX.1) EADDRNOTAVAIL Address not available (POSIX.1) EAFNOSUPPORT Address family not supported (POSIX.1) EAGAIN Resource temporarily unavailable (may be the same value as EWOULDBLOCK) (POSIX.1) EALREADY Connection already in progress (POSIX.1) EBADE Invalid exchange EBADF Bad file descriptor (POSIX.1) EBADFD File descriptor in bad state EBADMSG Bad message (POSIX.1) EBADR Invalid request descriptor EBADRQC Invalid request code EBADSLT Invalid slot EBUSY Device or resource busy (POSIX.1) ECANCELED Operation canceled (POSIX.1) ECHILD No child processes (POSIX.1) ECHRNG Channel number out of range ECOMM Communication error on send ECONNABORTED Connection aborted (POSIX.1) ECONNREFUSED Connection refused (POSIX.1) ECONNRESET Connection reset (POSIX.1) EDEADLK Resource deadlock avoided (POSIX.1) EDEADLOCK Synonym for EDEADLK EDESTADDRREQ Destination address required (POSIX.1) EDOM Mathematics argument out of domain of function (POSIX.1, C99) EDQUOT Disk quota exceeded (POSIX.1) EEXIST Fil
In C programming language, there is no direct support for error handling. You have to detect the failure and handle the error. In C programming language, return values represents success or failure. Inside a C program, when a function fails, you
Errno.h In C
should handle the errors accordingly, or at least record the errors in a log file. When errno.h windows you are running some program on Linux environment, you might notice that it gives some error number. For example, "Error no is : 17", efault which doesn't really say much. You really need to know what error number 17 means. This article shows all available error numbers along with it descriptions. This article might be a handy reference for you, when you encounter an error http://man7.org/linux/man-pages/man3/errno.3.html number and you would like to know what it means. In C programming language, there is an external variable called "errno". From this errno variable you can use some error handling functions to find out the error description and handle it appropriately. You have to include errno.h header file to use external variable errno. perror function prints error description in standard error. The strerror function returns a string describing the error code passed in the argument errnum. The following C http://www.thegeekstuff.com/2010/10/linux-error-codes/ code snippet tries to open a file through open system call. There are two flags in the open call. O_CREAT flag is to create a file, if the file does not exist. O_EXCL flag is used with O_CREAT, if the file is already exist open call will fail with the proper error number. $ cat fileopen.c #include
6 #define ESRCH 3 /* No such process */ 7 #define EINTR 4 /* Interrupted system call */ 8 #define EIO 5 /* I/O error */ 9 #define ENXIO 6 /* No such device or address */ 10 #define E2BIG 7 /* Arg list too long */ http://kernelhistory.sourcentral.org/linux-0.99.3/S/32.html 11 #define ENOEXEC 8 /* Exec format error */ 12 #define EBADF 9 /* Bad https://docs.python.org/2/library/errno.html file number */ 13 #define ECHILD 10 /* No child processes */ 14 #define EAGAIN 11 /* Try again */ 15 #define ENOMEM 12 /* Out of memory */ 16 #define EACCES 13 /* Permission denied */ 17 #define EFAULT 14 /* Bad address */ 18 #define ENOTBLK 15 /* Block device required */ 19 #define EBUSY 16 /* Device or resource busy error codes */ 20 #define EEXIST 17 /* File exists */ 21 #define EXDEV 18 /* Cross-device link */ 22 #define ENODEV 19 /* No such device */ 23 #define ENOTDIR 20 /* Not a directory */ 24 #define EISDIR 21 /* Is a directory */ 25 #define EINVAL 22 /* Invalid argument */ 26 #define ENFILE 23 /* File table overflow */ 27 #define EMFILE 24 /* Too many open files */ 28 #define ENOTTY 25 /* Not a typewriter linux error codes */ 29 #define ETXTBSY 26 /* Text file busy */ 30 #define EFBIG 27 /* File too large */ 31 #define ENOSPC 28 /* No space left on device */ 32 #define ESPIPE 29 /* Illegal seek */ 33 #define EROFS 30 /* Read-only file system */ 34 #define EMLINK 31 /* Too many links */ 35 #define EPIPE 32 /* Broken pipe */ 36 #define EDOM 33 /* Math argument out of domain of func */ 37 #define ERANGE 34 /* Math result not representable */ 38 #define EDEADLK 35 /* Resource deadlock would occur */ 39 #define ENAMETOOLONG 36 /* File name too long */ 40 #define ENOLCK 37 /* No record locks available */ 41 #define ENOSYS 38 /* Function not implemented */ 42 #define ENOTEMPTY 39 /* Directory not empty */ 43 #define ELOOP 40 /* Too many symbolic links encountered */ 44 #define EWOULDBLOCK EAGAIN /* Operation would block */ 45 #define ENOMSG 42 /* No message of desired type */ 46 #define EIDRM 43 /* Identifier removed */ 47 #define ECHRNG 44 /* Channel number out of range */ 48 #define EL2NSYNC 45 /* Level 2 not synchronized */ 49 #define EL3HLT 46 /* Level 3 halted */ 50 #define EL3RST 47 /* Level 3 reset */ 51 #define ELNRNG 48 /* Link number out of range */ 52 #define EUNATCH 49 /* Protocol driver not attached */ 53
This module makes available standard errno system symbols. The value of each symbol is the corresponding integer value. The names and descriptions are borrowed from linux/include/errno.h, which should be pretty all-inclusive. errno.errorcode¶ Dictionary providing a mapping from the errno value to the string name in the underlying system. For instance, errno.errorcode[errno.EPERM] maps to 'EPERM'. To translate a numeric error code to an error message, use os.strerror(). Of the following list, symbols that are not used on the current platform are not defined by the module. The specific list of defined symbols is available as errno.errorcode.keys(). Symbols available can include: errno.EPERM¶ Operation not permitted errno.ENOENT¶ No such file or directory errno.ESRCH¶ No such process errno.EINTR¶ Interrupted system call errno.EIO¶ I/O error errno.ENXIO¶ No such device or address errno.E2BIG¶ Arg list too long errno.ENOEXEC¶ Exec format error errno.EBADF¶ Bad file number errno.ECHILD¶ No child processes errno.EAGAIN¶ Try again errno.ENOMEM¶ Out of memory errno.EACCES¶ Permission denied errno.EFAULT¶ Bad address errno.ENOTBLK¶ Block device required errno.EBUSY¶ Device or resource busy errno.EEXIST¶ File exists errno.EXDEV¶ Cross-device link errno.ENODEV¶ No such device errno.ENOTDIR¶ Not a directory errno.EISDIR¶ Is a directory errno.EINVAL¶ Invalid argument errno.ENFILE¶ File table overflow errno.EMFILE¶ Too many open files errno.ENOTTY¶ Not a typewriter errno.ETXTBSY¶ Text file busy errno.EFBIG¶ File too large errno.ENOSPC¶ No space left on device errno.ESPIPE¶ Illegal seek errno.EROFS¶ Read-only file system errno.EMLINK¶ Too many links errno.EPIPE¶ Broken pipe errno.EDOM¶ Math argument out of domain of func errno.ERANGE¶ Math result not representable errno.EDEADLK¶ Resource deadlock would occ