Name
t_accept - accept a connect request
Syntax
#include <tiuser.h>
int fd;
int resfd;
struct t_call *call;
Description
This function is issued by a transport user to accept a
connect request. fd identifies the local transport endpoint
where the connect indication arrived, resfd specifies the
local transport endpoint where the connection is to be
established, and call contains information required by the
transport provider to complete the connection. call points
to a t_call structure which contains the following members:
struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
int sequence;
netbuf is described in intro(NSL). In call, addr is the
address of the caller, opt indicates any protocol-specific
parameters associated with the connection, udata points to
any user data to be returned to the caller, and sequence is
the value returned by t_listen that uniquely associates the
response with a previously received connect indication.
A transport user may accept a connection on either the same,
or on a different, local transport endpoint than the one on
which the connect indication arrived. If the same endpoint
is specified (that is, resfd=fd), the connection can be
accepted unless the following condition is true: The user
has received other indications on that endpoint but has not
responded to them (with t_accept or t_snddis). For this
condition, t_accept will fail and set t_errno to TBADF.
If a different transport endpoint is specified (resfd!=fd),
the endpoint must be bound to a protocol address and must be
in the T_IDLE state [see t_getstate(NSL)] before the
t_accept is issued.
For both types of endpoints, t_accept will fail and set
t_errno to TLOOK if there are indications (for example, a
connect or disconnect) waiting to be received on that
endpoint.
The values of parameters specified by opt and the syntax of
those values are protocol specific. The udata argument
enables the called transport user to send user data to the
caller and the amount of user data must not exceed the
limits supported by the transport provider as returned by
t_open or t_getinfo. If the len [see netbuf in intro(NSL)]
field of udata is zero, no data will be sent to the caller.
On failure, t_errno may be set to one of the following:
[TBADF] The specified file descriptor does not
refer to a transport endpoint, or the
user is illegally accepting a connection
on the same transport endpoint on which
the connect indication arrived.
[TOUTSTATE] The function was issued in the wrong
sequence on the transport endpoint
referenced by fd, or the transport
endpoint referred to by resfd is not in
the T_IDLE state.
[TACCES] The user does not have permission to
accept a connection on the responding
transport endpoint or use the specified
options.
[TBADOPT] The specified options were in an
incorrect format or contained illegal
information.
[TBADDATA] The amount of user data specified was not
within the bounds allowed by the
transport provider.
[TBADSEQ] An invalid sequence number was specified.
[TLOOK] An asynchronous event has occurred on the
transport endpoint referenced by fd and
requires immediate attention.
[TNOTSUPPORT] This function is not supported by the
underlying transport provider.
[TSYSERR] A system error has occurred during
execution of this function.
See Also
intro(NSL), t_connect(NSL), t_getstate(NSL), t_listen(NSL),
t_open(NSL), t_rcvconnect(NSL).
Network Programmer's Guide.
Diagnostics
Upon successful completion, a value of 0 is returned.
Otherwise, a value of -1 is returned and t_errno is set to
indicate the error.
Standards Conformance
t_accept is conformant with:
AT&T SVID Issue 2, Select Code 307-127.
(printed 6/18/89)