124 EMEDIUMTYPE Wrong medium type
123 ENOMEDIUM No medium found
122 EDQUOT Disk quota exceeded
121 EREMOTEIO Remote I/O error
120 EISNAM Is a named type file
119 ENAVAIL No XENIX semaphores available
118 ENOTNAM Not a XENIX named type file
117 EUCLEAN Structure needs cleaning
116 ESTALE Stale NFS file handle
115 EINPROGRESS +Operation now in progress
114 EALREADY Operation already in progress
113 EHOSTUNREACH No route to host
112 EHOSTDOWN Host is down
111 ECONNREFUSED Connection refused
110 ETIMEDOUT +Connection timed out
109 ETOOMANYREFS Too many references: cannot splice
108 ESHUTDOWN Cannot send after transport endpoint shutdown
107 ENOTCONN Transport endpoint is not connected
106 EISCONN Transport endpoint is already connected
105 ENOBUFS No buffer space available
104 ECONNRESET Connection reset by peer
103 ECONNABORTED Software caused connection abort
102 ENETRESET Network dropped connection on reset
101 ENETUNREACH Network is unreachable
100 ENETDOWN Network is down
99 EADDRNOTAVAIL Cannot assign requested address
98 EADDRINUSE Address already in use
97 EAFNOSUPPORT Address family not supported by protocol
96 EPFNOSUPPORT Protocol family not supported
95 EOPNOTSUPP Operation not supported
94 ESOCKTNOSUPPORT Socket type not supported
93 EPROTONOSUPPORT Protocol not supported
92 ENOPROTOOPT Protocol not available
91 EPROTOTYPE Protocol wrong type for socket
90 EMSGSIZE +Message too long
89 EDESTADDRREQ Destination address required
88 ENOTSOCK Socket operation on non-socket
87 EUSERS Too many users
86 ESTRPIPE Streams pipe error
85 ERESTART Interrupted system call should be restarted
84 EILSEQ Invalid or incomplete multibyte or wide character
83 ELIBEXEC Cannot exec a shared library directly
82 ELIBMAX Attempting to link in too many shared libraries
81 ELIBSCN .lib section in a.out corrupted
80 ELIBBAD Accessing a corrupted shared library
79 ELIBACC Can not access a needed shared library
78 EREMCHG Remote address changed
77 EBADFD File descriptor in bad state
76 ENOTUNIQ Name not unique on network
75 EOVERFLOW Value too large for defined data type
74 EBADMSG +Bad message
73 EDOTDOT RFS specific error
72 EMULTIHOP Multihop attempted
71 EPROTO Protocol error
70 ECOMM Communication error on send
69 ESRMNT Srmount error
68 EADV Advertise error
67 ENOLINK Link has been severed
66 EREMOTE Object is remote
65 ENOPKG Package not installed
64 ENONET Machine is not on the network
63 ENOSR Out of streams resources
62 ETIME Timer expired
61 ENODATA No data available
60 ENOSTR Device not a stream
59 EBFONT Bad font file format
57 EBADSLT Invalid slot
56 EBADRQC Invalid request code
55 ENOANO No anode
54 EXFULL Exchange full
53 EBADR Invalid request descriptor
52 EBADE Invalid exchange
51 EL2HLT Level 2 halted
50 ENOCSI No CSI structure available
49 EUNATCH Protocol driver not attached
48 ELNRNG Link number out of range
47 EL3RST Level 3 reset
46 EL3HLT Level 3 halted
45 EL2NSYNC Level 2 not synchronized
44 ECHRNG Channel number out of range
43 EIDRM Identifier removed
本文来自: () 详细出处参考:
42 ENOMSG No message of desired type
40 ELOOP Too many levels of symbolic links
39 ENOTEMPTY +Directory not empty
38 ENOSYS +Function not implemented
37 ENOLCK +No locks available
36 ENAMETOOLONG +File name too long
35 EDEADLK +Resource deadlock avoided
34 ERANGE +Numerical result out of range
33 EDOM +Numerical argument out of domain
32 EPIPE +Broken pipe
31 EMLINK +Too many links
30 EROFS +Read-only file system
29 ESPIPE +Illegal seek
28 ENOSPC +No space left on device
27 EFBIG +File too large
26 ETXTBSY Text file busy
25 ENOTTY +Inappropriate ioctl for device
24 EMFILE +Too many open files
23 ENFILE +Too many open files in system
22 EINVAL +Invalid argument
21 EISDIR +Is a directory
20 ENOTDIR +Not a directory
19 ENODEV +No such device
18 EXDEV +Invalid cross-device link
17 EEXIST +File exists
16 EBUSY +Device or resource busy
15 ENOTBLK Block device required
14 EFAULT +Bad address
13 EACCES +Permission denied
12 ENOMEM +Cannot allocate memory
11 EAGAIN +Resource temporarily unavailable
10 ECHILD +No child processes
9 EBADF +Bad file descriptor
8 ENOEXEC +Exec format error
7 E2BIG +Argument list too long
6 ENXIO +No such device or address
5 EIO +Input/output error
4 EINTR +Interrupted system call
3 ESRCH +No such process
2 ENOENT +No such file or directory
1 EPERM +Operation not permitted
# 0 -- Success
本文来自: () 详细出处参考:
Name
errno - number of last error
Synopsis
#include <>
Description
The <> header file defines the integer variable errno, which is set by system calls and some library functions in the event of an error to indicate what went wrong. Its value is significant only when the call returned an error (usually -1), and a function that does succeed is allowed to change errno.
Sometimes, when -1 is also a valid successful return value one has to zero errno before the call in order to detect possible errors.
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 macro. errno is thread-local; setting it in one thread does not affect its value in any other thread.
Valid error numbers are all non-zero; errno is never set to zero by any library function. 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
File exists (POSIX.1)
EFAULT
Bad address (POSIX.1)
EFBIG
File too large (POSIX.1)
- EHOSTDOWN
- Host is down
- EHOSTUNREACH
- Host is unreachable (POSIX.1)
- EIDRM
Identifier removed (POSIX.1)
EILSEQ
Illegal byte sequence (POSIX.1, C99)
- EINPROGRESS
- Operation in progress (POSIX.1)
- EINTR
Interrupted function call (POSIX.1)
EINVAL
Invalid argument (POSIX.1)
EIO
Input/output error (POSIX.1)
- EISCONN
- Socket is connected (POSIX.1)
- EISDIR
Is a directory (POSIX.1)
EISNAM
Is a named type file
- EKEYEXPIRED
- Key has expired
- EKEYREJECTED
- Key was rejected by service
- EKEYREVOKED
- Key has been revoked
- EL2HLT
Level 2 halted
- EL2NSYNC
- Level 2 not synchronized
- EL3HLT
Level 3 halted
EL3RST
Level 3 halted
- ELIBACC
- Cannot access a needed shared library
- ELIBBAD
- Accessing a corrupted shared library
- ELIBMAX
- Attempting to link in too many shared libraries
- ELIBSCN
- lib section in a.out corrupted
- ELIBEXEC
- Cannot exec a shared library directly
- ELOOP
Too many levels of symbolic links (POSIX.1)
- EMEDIUMTYPE
- Wrong medium type
- EMFILE
Too many open files (POSIX.1)
EMLINK
Too many links (POSIX.1)
- EMSGSIZE
- Message too long (POSIX.1)
- EMULTIHOP
- Multihop attempted (POSIX.1)
- ENAMETOOLONG
- Filename too long (POSIX.1)
- ENETDOWN
- Network is down (POSIX.1)
- ENETRESET
- Connection aborted by network (POSIX.1)
- ENETUNREACH
- Network unreachable (POSIX.1)
- ENFILE
Too many open files in system (POSIX.1)
- ENOBUFS
- No buffer space available (POSIX.1 (XSI STREAMS option))
- ENODATA
- No message is available on the STREAM head read queue (POSIX.1)
- ENODEV
No such device (POSIX.1)
ENOENT
No such file or directory (POSIX.1)
- ENOEXEC
- Exec format error (POSIX.1)
- ENOKEY
Required key not available
ENOLCK
No locks available (POSIX.1)
- ENOLINK
- Link has been severed (POSIX.1)
- ENOMEDIUM
- No medium found
- ENOMEM
Not enough space (POSIX.1)
ENOMSG
No message of the desired type (POSIX.1)
ENONET
Machine is not on the network
ENOPKG
Package not installed
- ENOPROTOOPT
- Protocol not available (POSIX.1)
- ENOSPC
No space left on device (POSIX.1)
ENOSR
No STREAM resources (POSIX.1 (XSI STREAMS option))
ENOSTR
Not a STREAM (POSIX.1 (XSI STREAMS option))
ENOSYS
Function not implemented (POSIX.1)
- ENOTBLK
- Block device required
- ENOTCONN
- The socket is not connected (POSIX.1)
- ENOTDIR
- Not a directory (POSIX.1)
- ENOTEMPTY
- Directory not empty (POSIX.1)
- ENOTSOCK
- Not a socket (POSIX.1)
- ENOTSUP
- Operation not supported (POSIX.1)
- ENOTTY
Inappropriate I/O control operation (POSIX.1)
- ENOTUNIQ
- Name not unique on network
- ENXIO
No such device or address (POSIX.1)
- EOPNOTSUPP
- Operation not supported on socket (POSIX.1)
(ENOTSUP and EOPNOTSUPP have the same value on Linux, but according to POSIX.1 these error values should be distinct.)
- EOVERFLOW
- Value too large to be stored in data type (POSIX.1)
- EPERM
Operation not permitted (POSIX.1)
- EPFNOSUPPORT
- Protocol family not supported
- EPIPE
Broken pipe (POSIX.1)
EPROTO
Protocol error (POSIX.1)
- EPROTONOSUPPORT
- Protocol not supported (POSIX.1)
- EPROTOTYPE
- Protocol wrong type for socket (POSIX.1)
- ERANGE
Result too large (POSIX.1, C99)
- EREMCHG
- Remote address changed
- EREMOTE
- Object is remote
- EREMOTEIO
- Remote I/O error
- ERESTART
- Interrupted system call should be restarted
- EROFS
Read-only file system (POSIX.1)
- ESHUTDOWN
- Cannot send after transport endpoint shutdown
- ESPIPE
Invalid seek (POSIX.1)
- ESOCKTNOSUPPORT
- Socket type not supported
- ESRCH
No such process (POSIX.1)
ESTALE
Stale file handle (POSIX.1))
- This error can occur for NFS and for other file systems
- ESTRPIPE
- Streams pipe error
- ETIME
Timer expired (POSIX.1 (XSI STREAMS option))
- (POSIX.1 says "STREAM ioctl() timeout")
- ETIMEDOUT
- Connection timed out (POSIX.1)
- ETXTBSY
- Text file busy (POSIX.1)
- EUCLEAN
- Structure needs cleaning
- EUNATCH
- Protocol driver not attached
- EUSERS
Too many users
- EWOULDBLOCK
- Operation would block (may be same value as EAGAIN) (POSIX.1)
- EXDEV
Improper link (POSIX.1)
EXFULL
Exchange full
Notes
A common mistake is to do
if (somecall() == -1) {
printf("somecall() failed\n");
if (errno == ...) { ... }
}
- where errno no longer needs to have the value it had upon return from somecall() (i.e., it may have been changed by the printf()). If the value of errno should be preserved across a library call, it must be saved:
if (somecall() == -1) {
int errsv = errno;
printf("somecall() failed\n");
if (errsv == ...) { ... }
}
- It was common in traditional C to declare errno manually (i.e., extern int errno) instead of including <>. Do not do this. It will not work with modern versions of the C library. However, on (very) old Unix systems, there may be no <> and the declaration is needed.
See Also
(3), (3), (3), (3)
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