accept(SSC)
accept --
accept a connection on a socket
Synopsis
cc [options] file -lsocket -lnsl
#include <sys/types.h>
#include <sys/socket.h>
int accept(int s, struct sockaddr *addr, size_t *addrlen);
Description
The argument
s
is a socket that has been created with
socket and
bound to an address with
bind,
and that is listening for connections after a call to
listen.
accept
extracts the first connection
on the queue of pending connections, creates
a new socket with the properties of
s,
and allocates a new file descriptor,
ns,
for the socket.
If no pending connections are
present on the queue and the socket is not marked
as non-blocking (O_NONBLOCK),
accept
blocks the caller until a connection is present.
If the socket is marked as non-blocking and no pending
connections are present on the queue,
accept
returns an error as described below.
accept
uses the
netconfig
file to determine the
STREAMS
device file name associated with
s.
This is the device on which the connect indication will be accepted.
The accepted socket,
ns,
is used to read and write data to and from the socket that connected
to ns; it is not used
to accept more connections.
The original socket
(s)
remains open for accepting further connections.
The argument
addr
is a result parameter that is filled in with
the address of the connecting entity
as it is known to the communications layer.
The exact format of the
addr
parameter is determined by the domain in which the communication
occurs.
addrlen
is a value-result parameter.
Initially, it contains the
amount of space pointed to by
addr;
on return it contains the length in bytes of the
address returned.
accept
is used with connection-based socket types, currently with
SOCK_STREAM.
It is possible to
select
a socket for the purpose of
an accept
by selecting it for read.
However, this will only indicate when a
connect indication is pending; it is still necessary to call
accept.
Files
/usr/lib/locale/locale/LC_MESSAGES/uxnsl
Return values
accept returns -1 on error.
If it succeeds, it returns a non-negative
integer that is a descriptor for the accepted socket.
Errors
accept will fail if:
EBADF-
The descriptor is invalid.
ECONNABORTED-
The connection was aborted.
EINTR-
The connection was interrupted.
EINVAL-
An invalid argument was passed.
EMFILE-
Ran out of file descriptors.
ENFILE-
Ran out of file table entries.
ENOBUFS-
Ran out of memory for STREAMS or socket buffers.
ENODEV-
The protocol family and type corresponding to
s
could not be found in the
netconfig file.
ENOMEM-
There was insufficient user memory available to complete the
operation.
ENOSR-
There were insufficient
STREAMS
resources available to complete
the operation.
ENOTSOCK-
The descriptor does not reference a socket.
EOPNOTSUPP-
The referenced socket is not of type
SOCK_STREAM.
EPROTO-
A protocol error has occurred;
for example, the
STREAMS
protocol stack has not been initialized.
EWOULDBLOCK-
The socket is marked as non-blocking and no connections
are present to be accepted.
References
bind(SSC),
connect(SSC),
listen(SSC),
netconfig(SFF),
socket(SSC)
RFC 2133
Notices
The type of address structure passed to accept depends on the
address family.
UNIX® domain sockets (address family AF_UNIX) require a
sockaddr_un structure as defined in sys/un.h;
Internet domain IPv4 sockets (address family AF_INET)
require a sockaddr_in structure as defined in
netinet/in.h;
Internet domain IPv6 sockets (address family AF_INET6)
require a sockaddr_in6 structure as defined in
netinet/in.h.
Other address families may require other structures.
Use the structure appropriate to the address family; cast the
structure address to a generic struct sockaddr * in the call to
accept
and pass the size of the structure in the addrlen argument.
The sockaddr structure has been modified from previous releases
to support variable length sockets. The net result of this modification
is that the family
member has been shortened to 8 bits and a
new 8-bit member inserted before it called len
. For more
information on the new sockaddr structures, see:
unix(ADMP)
and
inet(ADMP)
© 2005 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 - 01 June 2005