Editing Errno.h (section)

== POSIX errors ==

The [[Glibc|GNU C library]] (GLIBC) provides the additional [[POSIX]] error values macros in the header file {{Code|errno.h}}.<ref>{{Cite web |title=Error Codes (The GNU C Library) |url=https://www.gnu.org/software/libc/manual/html_node/Error-Codes.html |date=Mar 29, 2025| access-date=Apr 5, 2025 |website=www.gnu.org}}</ref> These are the descriptions of the macros provided by [[strerror]].

{| class="wikitable sortable"
|-
! Symbol !! Value<ref>{{cite web |author=<!-- not stated --> |title=Debugging: POSIX errors |url=https://docs.particle.io/reference/device-os/api/debugging/posix-errors/ |website=particle.io |access-date=Apr 5, 2025
}}</ref> !! Description
|-
| {{tt|EPERM}} || 1 || Operation not permitted
|-
| {{tt|ENOENT}} || 2 || No such file or directory
|-
| {{tt|ESRCH}} || 3 || No such process
|-
| {{tt|EINTR}} || 4 || Interrupted system call
|-
| {{tt|EIO}} || 5 || Input/output error
|-
| {{tt|ENXIO}} || 6 || No such device or address
|-
| {{tt|E2BIG}} || 7 || Argument list too long
|-
| {{tt|ENOEXEC}} || 8 || Exec format error
|-
| {{tt|EBADF}} || 9 || Bad file descriptor
|-
| {{tt|ECHILD}} || 10 || No child processes
|-
| {{tt|EAGAIN}} || 11 || Resource temporarily unavailable
|-
| {{tt|ENOMEM}} || 12 || Cannot allocate memory
|-
| {{tt|EACCES}} || 13 || Permission denied
|-
| {{tt|EFAULT}} || 14 || Bad address
|-
| {{tt|ENOTBLK}} || 15 || Block device required
|-
| {{tt|EBUSY}} || 16 || Device or resource busy
|-
| {{tt|EEXIST}} || 17 || File exists
|-
| {{tt|EXDEV}} || 18 || Invalid cross-device link
|-
| {{tt|ENODEV}} || 19 || No such device
|-
| {{tt|ENOTDIR}} || 20 || Not a directory
|-
| {{tt|EISDIR}} || 21 || Is a directory
|-
| {{tt|EINVAL}} || 22 || Invalid argument
|-
| {{tt|ENFILE}} || 23 || Too many open files in system
|-
| {{tt|EMFILE}} || 24 || Too many open files
|-
| {{tt|ENOTTY}} || 25 || Inappropriate ioctl for device
|-
| {{tt|ETXTBSY}} || 26 || Text file busy
|-
| {{tt|EFBIG}} || 27 || File too large
|-
| {{tt|ENOSPC}} || 28 || No space left on device
|-
| {{tt|ESPIPE}} || 29 || Illegal seek
|-
| {{tt|EROFS}} || 30 || Read-only file system
|-
| {{tt|EMLINK}} || 31 || Too many links
|-
| {{tt|EPIPE}} || 32 || Broken pipe
|-
| {{tt|EDOM}} || 33 || Numerical argument out of domain
|-
| {{tt|ERANGE}} || 34 || Numerical result out of range
|-
| {{tt|EDEADLK}} || 35 || Resource deadlock avoided
|-
| {{tt|ENAMETOOLONG}} || 36 || File name too long
|-
| {{tt|ENOLCK}} || 37 || No locks available
|-
| {{tt|ENOSYS}} || 38 || Function not implemented
|-
| {{tt|ENOTEMPTY}} || 39 || Directory not empty
|-
| {{tt|ELOOP}} || 40 || Too many levels of symbolic links
|-
| {{tt|ENOMSG}} || 42 || No message of desired type
|-
| {{tt|EIDRM}} || 43 || Identifier removed
|-
| {{tt|ECHRNG}} || 44 || Channel number out of range
|-
| {{tt|EL2NSYNC}} || 45 || Level 2 not synchronized
|-
| {{tt|EL3HLT}} || 46 || Level 3 halted
|-
| {{tt|EL3RST}} || 47 || Level 3 reset
|-
| {{tt|ELNRNG}} || 48 || Link number out of range
|-
| {{tt|EUNATCH}} || 49 || Protocol driver not attached
|-
| {{tt|ENOCSI}} || 50 || No CSI structure available
|-
| {{tt|EL2HLT}} || 51 || Level 2 halted
|-
| {{tt|EBADE}} || 52 || Invalid exchange
|-
| {{tt|EBADR}} || 53 || Invalid request descriptor
|-
| {{tt|EXFULL}} || 54 || Exchange full
|-
| {{tt|ENOANO}} || 55 || No anode
|-
| {{tt|EBADRQC}} || 56 || Invalid request code
|-
| {{tt|EBADSLT}} || 57 || Invalid slot
|-
| {{tt|EBFONT}} || 59 || Bad font file format
|-
| {{tt|ENOSTR}} || 60 || Device not a stream
|-
| {{tt|ENODATA}} || 61 || No data available
|-
| {{tt|ETIME}} || 62 || Timer expired
|-
| {{tt|ENOSR}} || 63 || Out of streams resources
|-
| {{tt|ENONET}} || 64 || Machine is not on the network
|-
| {{tt|ENOPKG}} || 65 || Package not installed
|-
| {{tt|EREMOTE}} || 66 || Object is remote
|-
| {{tt|ENOLINK}} || 67 || Link has been severed
|-
| {{tt|EADV}} || 68 || Advertise error
|-
| {{tt|ESRMNT}} || 69 || Srmount error
|-
| {{tt|ECOMM}} || 70 || Communication error on send
|-
| {{tt|EPROTO}} || 71 || Protocol error
|-
| {{tt|EMULTIHOP}} || 72 || Multihop attempted
|-
| {{tt|EDOTDOT}} || 73 || RFS specific error
|-
| {{tt|EBADMSG}} || 74 || Bad message
|-
| {{tt|EOVERFLOW}} || 75 || Value too large for defined data type
|-
| {{tt|ENOTUNIQ}} || 76 || Name not unique on network
|-
| {{tt|EBADFD}} || 77 || File descriptor in bad state
|-
| {{tt|EREMCHG}} || 78 || Remote address changed
|-
| {{tt|ELIBACC}} || 79 || Can not access a needed shared library
|-
| {{tt|ELIBBAD}} || 80 || Accessing a corrupted shared library
|-
| {{tt|ELIBSCN}} || 81 || .lib section in a.out corrupted
|-
| {{tt|ELIBMAX}} || 82 || Attempting to link in too many shared libraries
|-
| {{tt|ELIBEXEC}} || 83 || Cannot exec a shared library directly
|-
| {{tt|EILSEQ}} || 84 || Invalid or incomplete multibyte or wide character
|-
| {{tt|ERESTART}} || 85 || Interrupted system call should be restarted
|-
| {{tt|ESTRPIPE}} || 86 || Streams pipe error
|-
| {{tt|EUSERS}} || 87 || Too many users
|-
| {{tt|ENOTSOCK}} || 88 || Socket operation on non-socket
|-
| {{tt|EDESTADDRREQ}} || 89 || Destination address required
|-
| {{tt|EMSGSIZE}} || 90 || Message too long
|-
| {{tt|EPROTOTYPE}} || 91 || Protocol wrong type for socket
|-
| {{tt|ENOPROTOOPT}} || 92 || Protocol not available
|-
| {{tt|EPROTONOSUPPORT}} || 93 || Protocol not supported
|-
| {{tt|ESOCKTNOSUPPORT}} || 94 || Socket type not supported
|-
| {{tt|EOPNOTSUPP}} || 95 || Operation not supported
|-
| {{tt|EPFNOSUPPORT}} || 96 || Protocol family not supported
|-
| {{tt|EAFNOSUPPORT}} || 97 || Address family not supported by protocol
|-
| {{tt|EADDRINUSE}} || 98 || Address already in use
|-
| {{tt|EADDRNOTAVAIL}} || 99 || Cannot assign requested address
|-
| {{tt|ENETDOWN}} || 100 || Network is down
|-
| {{tt|ENETUNREACH}} || 101 || Network is unreachable
|-
| {{tt|ENETRESET}} || 102 || Network dropped connection on reset
|-
| {{tt|ECONNABORTED}} || 103 || Software caused connection abort
|-
| {{tt|ECONNRESET}} || 104 || Connection reset by peer
|-
| {{tt|ENOBUFS}} || 105 || No buffer space available
|-
| {{tt|EISCONN}} || 106 || Transport endpoint is already connected
|-
| {{tt|ENOTCONN}} || 107 || Transport endpoint is not connected
|-
| {{tt|ESHUTDOWN}} || 108 || Cannot send after transport endpoint shutdown
|-
| {{tt|ETOOMANYREFS}} || 109 || Too many references: cannot splice
|-
| {{tt|ETIMEDOUT}} || 110 || Connection timed out
|-
| {{tt|ECONNREFUSED}} || 111 || Connection refused
|-
| {{tt|EHOSTDOWN}} || 112 || Host is down
|-
| {{tt|EHOSTUNREACH}} || 113 || No route to host
|-
| {{tt|EALREADY}} || 114 || Operation already in progress
|-
| {{tt|EINPROGRESS}} || 115 || Operation now in progress
|-
| {{tt|ESTALE}} || 116 || Stale file handle
|-
| {{tt|EUCLEAN}} || 117 || Structure needs cleaning
|-
| {{tt|ENOTNAM}} || 118 || Not a XENIX named type file
|-
| {{tt|ENAVAIL}} || 119 || No XENIX semaphores available
|-
| {{tt|EISNAM}} || 120 || Is a named type file
|-
| {{tt|EREMOTEIO}} || 121 || Remote I/O error
|-
| {{tt|EDQUOT}} || 122 || Disk quota exceeded
|-
| {{tt|ENOMEDIUM}} || 123 || No medium found
|-
| {{tt|EMEDIUMTYPE}} || 124 || Wrong medium type
|-
| {{tt|ECANCELED}} || 125 || Operation canceled
|-
| {{tt|ENOKEY}} || 126 || Required key not available
|-
| {{tt|EKEYEXPIRED}} || 127 || Key has expired
|-
| {{tt|EKEYREVOKED}} || 128 || Key has been revoked
|-
| {{tt|EKEYREJECTED}} || 129 || Key was rejected by service
|-
| {{tt|EOWNERDEAD}} || 130 || Owner died
|-
| {{tt|ENOTRECOVERABLE}} || 131 || State not recoverable
|-
| {{tt|ERFKILL}} || 132 || Operation not possible due to RF-kill
|-
| {{tt|EHWPOISON}} || 133 || Memory page has hardware error
|-
| {{tt|ENOTSUP}} || 134 || Not supported parameter or option  
|-
| {{tt|ENOMEDIUM}} || 135 || Missing media 
|-
| {{tt|EILSEQ}} || 138 || Invalid multibyte sequence   
|-
| {{tt|EOVERFLOW}} || 139 || Value too large 
|-
| {{tt|ECANCELED}} || 140 || Asynchrononous operation stopped before normal completion  
|-
| {{tt|ENOTRECOVERABLE}} || 141 || State not recoverable
|-
| {{tt|EOWNERDEAD}} || 142 || Previous owner died
|-
| {{tt|ESTRPIPE}} || 143 || Streams  pipe error 
|}

The macro names and meanings for error codes are defined in the [https://pubs.opengroup.org/onlinepubs/9799919799/ POSIX Standards definition] however the numeric values are NOT, though by convention the values appear to be the same across different versions of Unix.{{citation needed|date=April 2025}} Programs should not rely on specific numeric values and should test code using the macro names specified in the ERRORS section of the [[man page]] of the associated function. For source [[Code readability|code readability]] and [[Software portability| portability]] the use of the standard macro names in code is highly recommended.<ref>{{cite web |author=<!-- not stated --> |date=Jan 26, 2025 |title=Checking for Errors |url=https://www.gnu.org/software/libc/manual/html_node/Checking-for-Errors.html |website=gnu.org |publisher=Free Software Foundation |access-date=Apr 6, 2025}} </ref><ref>{{cite book|arxiv=2401.10422 |doi=10.1145/3597503.3623323 |chapter=Semantic Analysis of Macro Usage for Portability |title=Proceedings of the IEEE/ACM 46th International Conference on Software Engineering |date=2024 |last1=Pappas |first1=Brent |last2=Gazzillo |first2=Paul |pages=1–12 |isbn=979-8-4007-0217-4 }} </ref> <!--The recommendation is generic, not specific but does refer extensively to porting kernel routines where error code macros are likely to be found in large numbers.   -->