errno.texi

一个C源代码分析器

@comment errno.h
@comment BSD: Text file busy
@deftypevr Macro int ETXTBSY
@comment errno 26 @c DO NOT REMOVE
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.
@end deftypevr

@comment errno.h
@comment POSIX.1: File too large
@deftypevr Macro int EFBIG
@comment errno 27 @c DO NOT REMOVE
File too big; the size of a file would be larger than allowed by the system.
@end deftypevr

@comment errno.h
@comment POSIX.1: No space left on device
@deftypevr Macro int ENOSPC
@comment errno 28 @c DO NOT REMOVE
No space left on device; write operation on a file failed because the
disk is full.
@end deftypevr

@comment errno.h
@comment POSIX.1: Illegal seek
@deftypevr Macro int ESPIPE
@comment errno 29 @c DO NOT REMOVE
Invalid seek operation (such as on a pipe).
@end deftypevr

@comment errno.h
@comment POSIX.1: Read-only file system
@deftypevr Macro int EROFS
@comment errno 30 @c DO NOT REMOVE
An attempt was made to modify something on a read-only file system.
@end deftypevr

@comment errno.h
@comment POSIX.1: Too many links
@deftypevr Macro int EMLINK
@comment errno 31 @c DO NOT REMOVE
Too many links; the link count of a single file is too large.
@code{rename} can cause this error if the file being renamed already has
as many links as it can take (@pxref{Renaming Files}).
@end deftypevr

@comment errno.h
@comment POSIX.1: Broken pipe
@deftypevr Macro int EPIPE
@comment errno 32 @c DO NOT REMOVE
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
@code{SIGPIPE} signal; this signal terminates the program if not handled
or blocked.  Thus, your program will never actually see @code{EPIPE}
unless it has handled or blocked @code{SIGPIPE}.
@end deftypevr

@comment errno.h
@comment ANSI: Numerical argument out of domain
@deftypevr Macro int EDOM
@comment errno 33 @c DO NOT REMOVE
Domain error; used by mathematical functions when an argument value does
not fall into the domain over which the function is defined.
@end deftypevr

@comment errno.h
@comment ANSI: Numerical result out of range
@deftypevr Macro int ERANGE
@comment errno 34 @c DO NOT REMOVE
Range error; used by mathematical functions when the result value is
not representable because of overflow or underflow.
@end deftypevr

@comment errno.h
@comment POSIX.1: Resource temporarily unavailable
@deftypevr Macro int EAGAIN
@comment errno 35 @c DO NOT REMOVE
Resource temporarily unavailable; the call might work if you try again
later.  The macro @code{EWOULDBLOCK} is another name for @code{EAGAIN};
they are always the same in the GNU C library.

This error can happen in a few different situations:

@itemize @bullet
@item
An operation that would block was attempted on an object that has
non-blocking mode selected.  Trying the same operation again will block
until some external condition makes it possible to read, write, or
connect (whatever the operation).  You can use @code{select} to find out
when the operation will be possible; @pxref{Waiting for I/O}.

@strong{Portability Note:} In older Unix many systems, this condition
was indicated by @code{EWOULDBLOCK}, which was a distinct error code
different from @code{EAGAIN}.  To make your program portable, you should
check for both codes and treat them the same.

@item
A temporary resource shortage made an operation impossible.  @code{fork}
can return this error.  It indicates that the shortage is expected to
pass, so your program can try the call again later and it may succeed.
It is probably a good idea to delay for a few seconds before trying it
again, to allow time for other processes to release scarce resources.
Such shortages are usually fairly serious and affect the whole system,
so usually an interactive program should report the error to the user
and return to its command loop.
@end itemize
@end deftypevr

@comment errno.h
@comment BSD: Operation would block
@deftypevr Macro int EWOULDBLOCK
@comment errno EAGAIN @c DO NOT REMOVE
In the GNU C library, this is another name for @code{EAGAIN} (above).
The values are always the same, on every operating system.

C libraries in many older Unix systems have @code{EWOULDBLOCK} as a
separate error code.
@end deftypevr

@comment errno.h
@comment BSD: Operation now in progress
@deftypevr Macro int EINPROGRESS
@comment errno 36 @c DO NOT REMOVE
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 @code{connect}; @pxref{Connecting}) never return
@code{EAGAIN}.
Instead, they return @code{EINPROGRESS} to indicate that the operation
has begun and will take some time.  Attempts to manipulate the object
before the call completes return @code{EALREADY}.
@end deftypevr

@comment errno.h
@comment BSD: Operation already in progress
@deftypevr Macro int EALREADY
@comment errno 37 @c DO NOT REMOVE
An operation is already in progress on an object that has non-blocking
mode selected.
@end deftypevr

@comment errno.h
@comment BSD: Socket operation on non-socket
@deftypevr Macro int ENOTSOCK
@comment errno 38 @c DO NOT REMOVE
A file that isn't a socket was specified when a socket is required.
@end deftypevr

@comment errno.h
@comment BSD: Message too long
@deftypevr Macro int EMSGSIZE
@comment errno 40 @c DO NOT REMOVE
The size of a message sent on a socket was larger than the supported
maximum size.  
@end deftypevr

@comment errno.h
@comment BSD: Protocol wrong type for socket
@deftypevr Macro int EPROTOTYPE
@comment errno 41 @c DO NOT REMOVE
The socket type does not support the requested communications protocol.
@end deftypevr

@comment errno.h
@comment BSD: Protocol not available
@deftypevr Macro int ENOPROTOOPT
@comment errno 42 @c DO NOT REMOVE
You specified a socket option that doesn't make sense for the
particular protocol being used by the socket.  @xref{Socket Options}.
@end deftypevr

@comment errno.h
@comment BSD: Protocol not supported
@deftypevr Macro int EPROTONOSUPPORT
@comment errno 43 @c DO NOT REMOVE
The socket domain does not support the requested communications protocol
(perhaps because the requested protocol is completely invalid.)
@xref{Creating a Socket}.
@end deftypevr

@comment errno.h
@comment BSD: Socket type not supported
@deftypevr Macro int ESOCKTNOSUPPORT
@comment errno 44 @c DO NOT REMOVE
The socket type is not supported.
@end deftypevr

@comment errno.h
@comment BSD: Operation not supported
@deftypevr Macro int EOPNOTSUPP
@comment errno 45 @c DO NOT REMOVE
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.
@end deftypevr

@comment errno.h
@comment BSD: Protocol family not supported
@deftypevr Macro int EPFNOSUPPORT
@comment errno 46 @c DO NOT REMOVE
The socket communications protocol family you requested is not supported.
@end deftypevr

@comment errno.h
@comment BSD: Address family not supported by protocol family
@deftypevr Macro int EAFNOSUPPORT
@comment errno 47 @c DO NOT REMOVE
The address family specified for a socket is not supported; it is
inconsistent with the protocol being used on the socket.  @xref{Sockets}.
@end deftypevr

@comment errno.h
@comment BSD: Address already in use
@deftypevr Macro int EADDRINUSE
@comment errno 48 @c DO NOT REMOVE
The requested socket address is already in use.  @xref{Socket Addresses}.
@end deftypevr

@comment errno.h
@comment BSD: Can't assign requested address
@deftypevr Macro int EADDRNOTAVAIL
@comment errno 49 @c DO NOT REMOVE
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.
@xref{Socket Addresses}.
@end deftypevr

@comment errno.h
@comment BSD: Network is down
@deftypevr Macro int ENETDOWN
@comment errno 50 @c DO NOT REMOVE
A socket operation failed because the network was down.
@end deftypevr

@comment errno.h
@comment BSD: Network is unreachable
@deftypevr Macro int ENETUNREACH
@comment errno 51 @c DO NOT REMOVE
A socket operation failed because the subnet containing the remost host
was unreachable.
@end deftypevr

@comment errno.h
@comment BSD: Network dropped connection on reset
@deftypevr Macro int ENETRESET
@comment errno 52 @c DO NOT REMOVE
A network connection was reset because the remote host crashed.
@end deftypevr

@comment errno.h
@comment BSD: Software caused connection abort
@deftypevr Macro int ECONNABORTED
@comment errno 53 @c DO NOT REMOVE
A network connection was aborted locally.
@end deftypevr

@comment errno.h
@comment BSD: Connection reset by peer
@deftypevr Macro int ECONNRESET
@comment errno 54 @c DO NOT REMOVE
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.
@end deftypevr

@comment errno.h
@comment BSD: No buffer space available
@deftypevr Macro int ENOBUFS
@comment errno 55 @c DO NOT REMOVE
The kernel's buffers for I/O operations are all in use.  In GNU, this
error is always synonymous with @code{ENOMEM}; you may get one or the
other from network operations.
@end deftypevr

@comment errno.h
@comment BSD: Socket is already connected
@deftypevr Macro int EISCONN
@comment errno 56 @c DO NOT REMOVE
You tried to connect a socket that is already connected.
@xref{Connecting}.
@end deftypevr

@comment errno.h
@comment BSD: Socket is not connected
@deftypevr Macro int ENOTCONN
@comment errno 57 @c DO NOT REMOVE
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.  For a connectionless socket (for datagram
protocols, such as UDP), you get @code{EDESTADDRREQ} instead.
@end deftypevr

@comment errno.h
@comment BSD: Destination address required
@deftypevr Macro int EDESTADDRREQ
@comment errno 39 @c DO NOT REMOVE
No default destination address was set for the socket.  You get this
error when you try to transmit data over a connectionless socket,
without first specifying a destination for the data with @code{connect}.
@end deftypevr

@comment errno.h
@comment BSD: Can't send after socket shutdown
@deftypevr Macro int ESHUTDOWN
@comment errno 58 @c DO NOT REMOVE
The socket has already been shut down.
@end deftypevr

@comment errno.h
@comment BSD: Too many references: can't splice
@deftypevr Macro int ETOOMANYREFS
@comment errno 59 @c DO NOT REMOVE
???
@end deftypevr

@comment errno.h
@comment BSD: Connection timed out
@deftypevr Macro int ETIMEDOUT
@comment errno 60 @c DO NOT REMOVE
A socket operation with a specified timeout received no response during
the timeout period.
@end deftypevr

@comment errno.h
@comment BSD: Connection refused
@deftypevr Macro int ECONNREFUSED
@comment errno 61 @c DO NOT REMOVE
A remote host refused to allow the network connection (typically because
it is not running the requested service).
@end deftypevr

@comment errno.h
@comment BSD: Too many levels of symbolic links
@deftypevr Macro int ELOOP