t_connect(3N) (Networking Support Utilities) t_connect(3N)
NAME
tconnect - establish a connection with another transport user
SYNOPSIS
#include <tiuser.h>
int tconnect(fd, sndcall, rcvcall)
int fd;
struct tcall *sndcall;
struct tcall *rcvcall;
DESCRIPTION
This function enables a transport user to request a connection to the
specified destination transport user. fd identifies the local
transport endpoint where communication will be established, while
sndcall and rcvcall point to a tcall structure that contains the
following members:
struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
int sequence;
sndcall specifies information needed by the transport provider to
establish a connection and rcvcall specifies information that is
associated with the newly established connection.
netbuf is described in intro(3). In sndcall, addr specifies the
protocol address of the destination transport user, opt presents any
protocol-specific information that might be needed by the transport
provider, udata points to optional user data that may be passed to
the destination transport user during connection establishment, and
sequence has no meaning for this function.
On return in rcvcall, addr returns the protocol address associated
with the responding transport endpoint, opt presents any protocol-
specific information associated with the connection, udata points to
optional user data that may be returned by the destination transport
user during connection establishment, and sequence has no meaning for
this function.
The opt argument implies no structure on the options that may be
passed to the transport provider. The transport provider is free to
specify the structure of any options passed to it. These options are
specific to the underlying protocol of the transport provider. The
user may choose not to negotiate protocol options by setting the len
field of opt to zero. In this case, the provider may use default
options.
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t_connect(3N) (Networking Support Utilities) t_connect(3N)
The udata argument enables the caller to pass user data to the
destination transport user and receive user data from the destination
user during connection establishment. However, the amount of user
data must not exceed the limits supported by the transport provider
as returned in the connect field of the info argument of topen(3N)
or tgetinfo(3N). If the len [see netbuf in intro(3)] field of udata
is zero in sndcall, no data will be sent to the destination transport
user.
On return, the addr, opt, and udata fields of rcvcall will be updated
to reflect values associated with the connection. Thus, the maxlen
[see netbuf in intro(3)] field of each argument must be set before
issuing this function to indicate the maximum size of the buffer for
each. However, rcvcall may be NULL, in which case no information is
given to the user on return from tconnect.
By default, tconnect executes in synchronous mode, and will wait for
the destination user's response before returning control to the local
user. A successful return (i.e., return value of zero) indicates
that the requested connection has been established. However, if
ONDELAY or ONONBLOCK is set (via topen or fcntl), tconnect
executes in asynchronous mode. In this case, the call will not wait
for the remote user's response, but will return control immediately
to the local user and return -1 with terrno set to TNODATA to
indicate that the connection has not yet been established. In this
way, the function simply initiates the connection establishment
procedure by sending a connect request to the destination transport
user.
On failure, terrno may be set to one of the following:
[TBADF] The specified file descriptor does not refer to a
transport endpoint.
[TOUTSTATE] The function was issued in the wrong sequence.
[TNODATA] ONDELAY or ONONBLOCK was set, so the function
successfully initiated the connection
establishment procedure, but did not wait for a
response from the remote user.
[TBADADDR] The specified protocol address was in an incorrect
format or contained illegal information.
[TBADOPT] The specified protocol 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.
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t_connect(3N) (Networking Support Utilities) t_connect(3N)
[TACCES] The user does not have permission to use the
specified address or options.
[TBUFOVFLW] The number of bytes allocated for an incoming
argument is not sufficient to store the value of
that argument. If executed in synchronous mode,
the provider's state, as seen by the user, changes
to TDATAXFER, and the connect indication
information to be returned in rcvcall is
discarded.
[TLOOK] An asynchronous event has occurred on this
transport endpoint 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(3), t_accept(3N), t_getinfo(3N), t_listen(3N), t_open(3N),
t_optmgmt(3N), t_rcvconnect(3N).
Programmer's Guide: Networking Interfaces.
DIAGNOSTICS
tconnect returns 0 on success and -1 on failure and terrno is set
to indicate the error.
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