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The error code macros are defined in the header file `errno.h'. All of them expand into integer constant values. Some of these error codes can't occur on the GNU system, but they can occur using the GNU library on other systems.
Macro: int EPERM
Operation not permitted; only the owner of the file (or other resource) or processes with special privileges can perform the operation.
Macro: int ENOENT
No such file or directory. This is a "file doesn't exist" error for ordinary files that are referenced in contexts where they are expected to already exist.
Macro: int ESRCH
No process matches the specified process ID.
Macro: int EINTR
Interrupted function call; an asynchronous signal occured and prevented completion of the call. When this happens, you should try the call again.
You can choose to have functions resume after a signal that is handled,
rather than failing with
EINTR; see section Primitives Interrupted by Signals.
Macro: int EIO
Input/output error; usually used for physical read or write errors.
Macro: int ENXIO
No such device or address. The system tried to use the device represented by a file you specified, and it couldn't find the device. This can mean that the device file was installed incorrectly, or that the physical device is missing or not correctly attached to the computer.
Macro: int E2BIG
Argument list too long; used when the arguments passed to a new program
being executed with one of the
exec functions (see section Executing a File) occupy too much memory space. This condition never arises in the
Macro: int ENOEXEC
Invalid executable file format. This condition is detected by the
exec functions; see section Executing a File.
Macro: int EBADF
Bad file descriptor; for example, I/O on a descriptor that has been closed or reading from a descriptor open only for writing (or vice versa).
Macro: int ECHILD
There are no child processes. This error happens on operations that are supposed to manipulate child processes, when there aren't any processes to manipulate.
Macro: int EDEADLK
Deadlock avoided; allocating a system resource would have resulted in a deadlock situation. The system does not guarantee that it will notice all such situations. This error means you got lucky and the system noticed; it might just hang. See section File Locks, for an example.
Macro: int ENOMEM
No memory available. The system cannot allocate more virtual memory because its capacity is full.
Macro: int EACCES
Permission denied; the file permissions do not allow the attempted operation.
Macro: int EFAULT
Bad address; an invalid pointer was detected.
Macro: int ENOTBLK
A file that isn't a block special file was given in a situation that requires one. For example, trying to mount an ordinary file as a file system in Unix gives this error.
Macro: int EBUSY
Resource busy; a system resource that can't be shared is already in use. For example, if you try to delete a file that is the root of a currently mounted filesystem, you get this error.
Macro: int EEXIST
File exists; an existing file was specified in a context where it only makes sense to specify a new file.
Macro: int EXDEV
An attempt to make an improper link across file systems was detected.
This happens not only when you use
link (see section Hard Links) but
also when you rename a file with
rename (see section Renaming Files).
Macro: int ENODEV
The wrong type of device was given to a function that expects a particular sort of device.
Macro: int ENOTDIR
A file that isn't a directory was specified when a directory is required.
Macro: int EISDIR
File is a directory; attempting to open a directory for writing gives this error.
Macro: int EINVAL
Invalid argument. This is used to indicate various kinds of problems with passing the wrong argument to a library function.
Macro: int EMFILE
The current process has too many files open and can't open any more. Duplicate descriptors do count toward this limit.
Macro: int ENFILE
There are too many distinct file openings in the entire system. Note that any number of linked channels count as just one file opening; see section Linked Channels. This error never occurs in the GNU system.
Macro: int ENOTTY
Inappropriate I/O control operation, such as trying to set terminal modes on an ordinary file.
Macro: int ETXTBSY
An attempt to execute a file that is currently open for writing, or write to a file that is currently being executed. (The name stands for "text file busy".) This is not an error in the GNU system; the text is copied as necessary.
Macro: int EFBIG
File too big; the size of a file would be larger than allowed by the system.
Macro: int ENOSPC
No space left on device; write operation on a file failed because the disk is full.
Macro: int ESPIPE
Invalid seek operation (such as on a pipe).
Macro: int EROFS
An attempt was made to modify something on a read-only file system.
Macro: int EMLINK
Too many links; the link count of a single file is too large.
rename can cause this error if the file being renamed already has
as many links as it can take (see section Renaming Files).
Macro: int EPIPE
Broken pipe; there is no process reading from the other end of a pipe.
Every library function that returns this error code also generates a
SIGPIPE signal; this signal terminates the program if not handled
or blocked. Thus, your program will never actually see
unless it has handled or blocked
Macro: int EDOM
Domain error; used by mathematical functions when an argument value does not fall into the domain over which the function is defined.
Macro: int ERANGE
Range error; used by mathematical functions when the result value is not representable because of overflow or underflow.
Macro: int EAGAIN
Resource temporarily unavailable; the call might work if you try again
fork returns error code
EAGAIN for such a
Macro: int EWOULDBLOCK
An operation that would block was attempted on an object that has non-blocking mode selected.
Portability Note: In 4.4BSD and GNU,
EAGAIN are the same. Earlier versions of BSD (see section Berkeley Unix) have two distinct codes, and use
EWOULDBLOCK to indicate
an I/O operation that would block on an object with non-blocking mode
EAGAIN for other kinds of errors.
Macro: int EINPROGRESS
An operation that cannot complete immediately was initiated on an object
that has non-blocking mode selected. Some functions that must always
block (such as
connect; see section Making a Connection) never return
Instead, they return
EINPROGRESS to indicate that the operation
has begun and will take some time. Attempts to manipulate the object
before the call completes return
Macro: int EALREADY
An operation is already in progress on an object that has non-blocking mode selected.
Macro: int ENOTSOCK
A file that isn't a socket was specified when a socket is required.
Macro: int EDESTADDRREQ
No destination address was supplied on a socket operation that needed one.
Macro: int EMSGSIZE
The size of a message sent on a socket was larger than the supported maximum size.
Macro: int EPROTOTYPE
The socket type does not support the requested communications protocol.
Macro: int ENOPROTOOPT
You specified a socket option that doesn't make sense for the particular protocol being used by the socket. See section Socket Options.
Macro: int EPROTONOSUPPORT
The socket domain does not support the requested communications protocol (perhaps because the requested protocol is completely invalid.) See section Creating a Socket.
Macro: int ESOCKTNOSUPPORT
The socket type is not supported.
Macro: int EOPNOTSUPP
The operation you requested is not supported. Some socket functions don't make sense for all types of sockets, and others may not be implemented for all communications protocols.
Macro: int EPFNOSUPPORT
The socket communications protocol family you requested is not supported.
Macro: int EAFNOSUPPORT
The address family specified for a socket is not supported; it is inconsistent with the protocol being used on the socket. See section Sockets.
Macro: int EADDRINUSE
The requested socket address is already in use. See section Socket Addresses.
Macro: int EADDRNOTAVAIL
The requested socket address is not available; for example, you tried to give a socket a name that doesn't match the local host name. See section Socket Addresses.
Macro: int ENETDOWN
A socket operation failed because the network was down.
Macro: int ENETUNREACH
A socket operation failed because the subnet containing the remost host was unreachable.
Macro: int ENETRESET
A network connection was reset because the remote host crashed.
Macro: int ECONNABORTED
A network connection was aborted locally.
Macro: int ECONNRESET
A network connection was closed for reasons outside the control of the local host, such as by the remote machine rebooting or an unrecoverable protocol violation.
Macro: int ENOBUFS
The kernel's buffers for I/O operations are all in use.
Macro: int EISCONN
You tried to connect a socket that is already connected. See section Making a Connection.
Macro: int ENOTCONN
The socket is not connected to anything. You get this error when you try to transmit data over a socket, without first specifying a destination for the data.
Macro: int ESHUTDOWN
The socket has already been shut down.
Macro: int ETIMEDOUT
A socket operation with a specified timeout received no response during the timeout period.
Macro: int ECONNREFUSED
A remote host refused to allow the network connection (typically because it is not running the requested service).
Macro: int ELOOP
Too many levels of symbolic links were encountered in looking up a file name. This often indicates a cycle of symbolic links.
Macro: int ENAMETOOLONG
Filename too long (longer than
PATH_MAX; see section Limits on File System Capacity) or host name too long (in
sethostname; see section Host Identification).
Macro: int EHOSTDOWN
The remote host for a requested network connection is down.
Macro: int EHOSTUNREACH
The remote host for a requested network connection is not reachable.
Macro: int ENOTEMPTY
Directory not empty, where an empty directory was expected. Typically, this error occurs when you are trying to delete a directory.
Macro: int EUSERS
The file quota system is confused because there are too many users.
Macro: int EDQUOT
The user's disk quota was exceeded.
Macro: int ESTALE
Stale NFS file handle. This indicates an internal confusion in the NFS system which is due to file system rearrangements on the server host. Repairing this condition usually requires unmounting and remounting the NFS file system on the local host.
Macro: int EREMOTE
An attempt was made to NFS-mount a remote file system with a file name that already specifies an NFS-mounted file. (This is an error on some operating systems, but we expect it to work properly on the GNU system, making this error code impossible.)
Macro: int ENOLCK
No locks available. This is used by the file locking facilities; see section File Locks. This error never occurs in the GNU system.
Macro: int ENOSYS
Function not implemented. Some functions have commands or options defined that might not be supported in all implementations, and this is the kind of error you get if you request them and they are not supported.
Macro: int EBACKGROUND
In the GNU system, servers supporting the
term protocol return
this error for certain operations when the caller is not in the
foreground process group of the terminal. Users do not usually see this
error because functions such as
it into a
SIGTTOU signal. See section Job Control,
for information on process groups and these signals.
Macro: int ED
The experienced user will know what is wrong.
Macro: int EGREGIOUS
You did what?
Macro: int EIEIO
Go home and have a glass of warm, dairy-fresh milk.
Macro: int EGRATUITOUS
This error code has no purpose.
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