#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 /* Argument 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 67 /* Link has been severed */
#define EADV 68 /* Advertise error */
#define ESRMNT 69 /* Srmount error */
#define ECOMM 70 /* Communication error on send */
#define EPROTO 71 /* Protocol error */
#define EMULTIHOP 72 /* Multihop attempted */
#define EDOTDOT 73 /* RFS specific error */
#define EBADMSG 74 /* Not a data message */
#define EOVERFLOW 75 /* Value too large for defined data type */
#define ENOTUNIQ 76 /* Name not unique on network */
#define EBADFD 77 /* File descriptor in bad state */
#define EREMCHG 78 /* Remote address changed */
#define ELIBACC 79 /* Can not access a needed shared library */
#define ELIBBAD 80 /* Accessing a corrupted shared library */
#define ELIBSCN 81 /* .lib section in a.out corrupted */
#define ELIBMAX 82 /* Attempting to link in too many shared libraries */
#define ELIBEXEC 83 /* Cannot exec a shared library directly */
#define EILSEQ 84 /* Illegal byte sequence */
#define ERESTART 85 /* Interrupted system call should be restarted */
#define ESTRPIPE 86 /* Streams pipe error */
#define EUSERS 87 /* Too many users */
#define ENOTSOCK 88 /* Socket operation on non-socket */
#define EDESTADDRREQ 89 /* Destination address required */
#define EMSGSIZE 90 /* Message too long */
#define EPROTOTYPE 91 /* Protocol wrong type for socket */
#define ENOPROTOOPT 92 /* Protocol not available */
#define EPROTONOSUPPORT 93 /* Protocol not supported */
#define ESOCKTNOSUPPORT 94 /* Socket type not supported */
#define EOPNOTSUPP 95 /* Operation not supported on transport endpoint */
#define EPFNOSUPPORT 96 /* Protocol family not supported */
#define EAFNOSUPPORT 97 /* Address family not supported by protocol */
#define EADDRINUSE 98 /* Address already in use */
#define EADDRNOTAVAIL 99 /* Cannot assign requested address */
#define ENETDOWN 100 /* Network is down */
#define ENETUNREACH 101 /* Network is unreachable */
#define ENETRESET 102 /* Network dropped connection because of reset */
#define ECONNABORTED 103 /* Software caused connection abort */
#define ECONNRESET 104 /* Connection reset by peer */
#define ENOBUFS 105 /* No buffer space available */
#define EISCONN 106 /* Transport endpoint is already connected */
#define ENOTCONN 107 /* Transport endpoint is not connected */
#define ESHUTDOWN 108 /* Cannot send after transport endpoint shutdown */
#define ETOOMANYREFS 109 /* Too many references: cannot splice */
#define ETIMEDOUT 110 /* Connection timed out */
#define ECONNREFUSED 111 /* Connection refused */
#define EHOSTDOWN 112 /* Host is down */
#define EHOSTUNREACH 113 /* No route to host */
#define EALREADY 114 /* Operation already in progress */
#define EINPROGRESS 115 /* Operation now in progress */
#define ESTALE 116 /* Stale NFS file handle */
#define EUCLEAN 117 /* Structure needs cleaning */
#define ENOTNAM 118 /* Not a XENIX named type file */
#define ENAVAIL 119 /* No XENIX semaphores available */
#define EISNAM 120 /* Is a named type file */
#define EREMOTEIO 121 /* Remote I/O error */
#define EDQUOT 122 /* Quota exceeded */
#define ENOMEDIUM 123 /* No medium found */
#define EMEDIUMTYPE 124 /* Wrong medium type */
E2BIG-- The argument list passed to the function was too long.EACCESS-- Access denied! The user running the program doesn't have permission to access a file, directory, and so forth.EAGAIN-- The required resource is temporarily unavailable; if you try the operation again later, it might succeed.EBADF-- A function tried to use a bad file descriptor (it doesn't refer to an open file, for example, or it was used in an attempt to write to a file that was opened read-only).EBUSY-- The requested resource is unavailable. For example, attempting to remove a directory while another application is reading it. Note the ambiguity betweenEBUSYandEAGAIN; obviously you'd be able to remove the directory later, when the reading program has finished.ECHILD-- Thewait()orwaitpid()function tried to wait for a child process to exit, but all children have already exited.EDEADLK-- A resource deadlock would occur if the request continued. Note that this is not the sort of deadlock you get in multithreaded code --errnoand its friends definitely can't help you track those down.EDOM-- The input argument is outside of the domain of a mathematical function.EEXIST-- The file already exists, and that's a problem. For example, if you callmkdir()with a path that names an existing file or directory.EFAULT-- One of the function arguments refers to an invalid address. Most implementations can't detect this (your program receives aSIGSEGFAULTsignal and exit instead).EFBIG-- The request would cause a file to expand past the implementation-defined maximum file size. This is generally around 2GB, but most modern file systems support much larger files, sometimes requiring 64-bit versions of theread()/write()andlseek()functions.EINTR-- The function was interrupted by a signal, which was caught by a signal handler in the program, and the signal handler returned normally.EINVAL-- You passed an invalid argument to the function.EIO-- An I/O error occurred; this is usually generated in response to hardware problems.EISDIR-- You called a function that requires a file argument with a directory argument.ENFILE-- Too many files are already open in this process. Each process hasOPEN_MAXfile descriptors, and you're trying to open (OPEN_MAX + 1) files. Remember that file descriptors include things like sockets.ENLINK-- The function call would cause a file to have more thanLINK_MAXlinks.ENAMETOOLONG-- You've created a path name longer thanPATH_MAX, or you've created a file or directory name longer thanNAME_MAX.ENFILE-- The system has too many simultaneously open files. This should be a temporary condition, and it is unlikely to happen on a modern system.ENODEV-- No such device or you're attempting to do something inappropriate for the specified device (don't try reading from an ancient line printer, for example).ENOENT-- No such file was found or the specified path name doesn't exist.ENOEXEC-- You tried to run a file that isn't executable.ENOLCK-- No locks are available; you've reached a system-wide limit on file or record locks.ENOMEM-- The system is out of memory. Traditionally, applications (and the OS itself) don't handle this gracefully, which is why you need to have more RAM than you expect to use, especially on systems that can't dynamically increase the size of the on-disk swap space.ENOSPC-- No space left on the device. You've tried to write to or create a file on a device that's full. Again, it's traditional for applications and the OS to not handle this gracefully.ENOSYS-- The system doesn't support that function. For example, if you callsetpgid()on a system without job control, you'll get anENOSYSerror.ENOTDIR-- The specified path name needs to be a directory, but it isn't. This is the opposite of theEISDIRerror.ENOTEMPTY-- The specified directory isn't empty, but it needs to be. Note that an empty directory still contains the . and .. entries.ENOTTY-- You've attempted an I/O control operation on a file or special file that doesn't support that operation. Don't try setting the baud rate on a directory, for example.ENXIO-- You've attempted an I/O request on a special file for a device that doesn't exist.EPERM-- The operation isn't permitted; you don't have permission to access the specified resource.EPIPE-- You've attempted to read from or write to a pipe that doesn't exist any more. One of the programs in the pipe chain has closed its part of the stream (by exiting, for example).ERANGE-- You've called a function, and the return value is too large to be represented by the return type. For example, if a function returns anunsigned charvalue but calculated a result of 256 or more (or-1or less),errnowould be set toERANGEand the function would return some irrelevant value. In cases like this, it's important to check your input data for sanity, or checkerrnoafter every call.EROFS-- You attempted to modify a file or directory stored on a read-only file system (or a file system that was mounted in read-only mode).ESPIPE-- You attempted to seek on a pipe or First In, First Out (FIFO).ESRCH-- You've specified an invalid process ID or process group.EXDEV-- You've attempted an operation that would move a link across devices. For example, UNIX filesystems don't let you move a file between file systems (instead, you have to copy the file, then delete the original).