List of error codes (Internet domain)
In the following list of networking error codes,
the protocol or operation during which the error is
likely to occur is given at the beginning of the explanation.
------------------------------------------------------------------- Error Name Description Explanation ------------------------------------------------------------------- EALREADY Operation already in progress ------------------------------------------------------------------- EINPROGRESS Operation now in progress ------------------------------------------------------------------- EWOULDBLOCK Operation would block -------------------------------------------------------------------
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Error Name Description Explanation
--------------------------------------------------------
EADDRINUSE Address already TCP and UDP. An
in use attempt was made to
create a socket with
a port which has
already been
allocated.
--------------------------------------------------------
EADDRNOTAVAIL Can't assign TCP and UDP. An
requested attempt was made to
address create a socket with
a network address
for which no network
interface exists.
--------------------------------------------------------
EAFNOSUPPORT Address family
not supported
by protocol
family
--------------------------------------------------------
EDESTADDRREQ Destination
address
required
--------------------------------------------------------
EMSGSIZE Message too
long
--------------------------------------------------------
ENOTSOCK Socket
operation on
non-socket
--------------------------------------------------------
EOPNOTSUPP Operation not
supported on
socket
--------------------------------------------------------
EPFNOSUPPORT Protocol family
not supported
--------------------------------------------------------
EPROTONOSUPPORT Protocol not Creating a socket.
supported Unknown protocol or
protocol not
supported.
--------------------------------------------------------
EPROTOTYPE Protocol wrong Creating a socket.
type for socket Socket type request
has no supporting
protocol.
--------------------------------------------------------
ESOCKTNOSUPPORT Socket type not
supported
--------------------------------------------------------
-----------------------------------------------------
Error Name Description Explanation
-----------------------------------------------------
ECONNABORTED Software caused
connection
abort
-----------------------------------------------------
ECONNREFUSED Connection Socket connection.
refused The host refused
service for some
reason. This error
is usually caused by
a server process not
being present at the
requested name.
-----------------------------------------------------
ECONNRESET Connection TCP. The remote
reset by peer peer forced the
session to be
closed.
-----------------------------------------------------
EISCONN Socket is IP and UDP. An
already attempt was made to
connected establish a
connection on a
socket that already
has one or an
attempt was made to
send a datagram with
the destination
address specified
and the socket is
already connected.
TCP. An attempt was
made to establish a
connection on a
socket that already
has one.
-----------------------------------------------------
ENETDOWN Network is down Socket connection.
Status information
received by the
client host from the
underlying
communication
services indicates
the net or the
remote host is down.
-----------------------------------------------------
ENETRESET Network dropped
connection on
reset
-----------------------------------------------------
ENETUNREACH Network is
unreachable
-----------------------------------------------------
ENOBUFS No buffer space TCP, IP, and UDP.
available Any Socket
Operation. The
system lacks
sufficient memory
for an internal data
structure.
-----------------------------------------------------
ENOTCONN Socket is not UDP. An attempt was
connected made to send a
datagram, but no
destination address
is specified, and
the socket has not
been connected.
-----------------------------------------------------
ESHUTDOWN Cannot send
after socket
shutdown
-----------------------------------------------------
ETIMEDOUT Connection Socket connection.
timed out After failing to
establish a
connection during a
period of time
(excessive
retransmissions),
the system decided
there was no point
in retrying any
more. The cause for
this error is
usually that the
remote host is down
or that problems in
the network resulted
in transmissions
being lost.
-----------------------------------------------------
-----------------------------------------------------
Error Name Description Explanation
-----------------------------------------------------
EHOSTDOWN Host is down Socket connection.
Status information
received by the
client host from the
underlying
communication
services indicates
the net or the
remote host is down.
-----------------------------------------------------
EHOSTUNREACH No route to Socket connection.
host These operational
errors can occur
either because the
network or host is
unknown (no route to
the host or network
is present) or
because status
information to that
effect has been
delivered to the
client host by the
underlying
communication
services.
-----------------------------------------------------
ENOPROTOOPT Protocol not
available
-----------------------------------------------------