This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
Some of the functionality described on this reference page extends
the ISO C standard. Any conflict between the requirements described
here and the ISO C standard is unintentional. This volume of
POSIX.1‐2008 defers to the ISO C standard.
The ISO C standard only requires the symbols [EDOM], [EILSEQ], and
[ERANGE] to be defined.
The <errno.h> header shall provide a declaration or definition for
errno. The symbol errno shall expand to a modifiable lvalue of type
int. It is unspecified whether errno is a macro or an identifier
declared with external linkage. If a macro definition is suppressed
in order to access an actual object, or a program defines an
identifier with the name errno, the behavior is undefined.
The <errno.h> header shall define the following macros which shall
expand to integer constant expressions with type int, distinct
positive values (except as noted below), and which shall be suitable
for use in #if preprocessing directives:
E2BIG Argument list too long.
EACCES Permission denied.
Address in use.
Address not available.
Address family not supported.
EAGAIN Resource unavailable, try again (may be the same value as
Connection already in progress.
EBADF Bad file descriptor.
EBUSY Device or resource busy.
ECHILD No child processes.
Resource deadlock would occur.
Destination address required.
EDOM Mathematics argument out of domain of function.
EEXIST File exists.
EFAULT Bad address.
EFBIG File too large.
Host is unreachable.
EIDRM Identifier removed.
EILSEQ Illegal byte sequence.
Operation in progress.
EINTR Interrupted function.
EINVAL Invalid argument.
EIO I/O error.
Socket is connected.
EISDIR Is a directory.
ELOOP Too many levels of symbolic links.
EMFILE File descriptor value too large.
EMLINK Too many links.
Message too large.
Filename too long.
Network is down.
Connection aborted by network.
ENFILE Too many files open in system.
No buffer space available.
No message is available on the STREAM head read queue.
ENODEV No such device.
ENOENT No such file or directory.
Executable file format error.
ENOLCK No locks available.
ENOMEM Not enough space.
ENOMSG No message of the desired type.
Protocol not available.
ENOSPC No space left on device.
ENOSR No STREAM resources.
ENOSTR Not a STREAM.
ENOSYS Function not supported.
The socket is not connected.
Not a directory or a symbolic link to a directory.
Directory not empty.
State not recoverable.
Not a socket.
Not supported (may be the same value as [EOPNOTSUPP]).
ENOTTY Inappropriate I/O control operation.
ENXIO No such device or address.
Operation not supported on socket (may be the same value as
Value too large to be stored in data type.
Previous owner died.
EPERM Operation not permitted.
EPIPE Broken pipe.
EPROTO Protocol error.
Protocol not supported.
Protocol wrong type for socket.
ERANGE Result too large.
EROFS Read-only file system.
ESPIPE Invalid seek.
ESRCH No such process.
ETIME Stream ioctl() timeout.
Connection timed out.
Text file busy.
Operation would block (may be the same value as [EAGAIN]).
EXDEV Cross-device link.
The following sections are informative.
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
IEEE/The Open Group 2013 errno.h(0P)