t_connect(3) CLIX t_connect(3)
NAME
t_connect - Establishes a connection with another transport user
LIBRARY
Transport Layer Interface (TLI) Library (libnsl_s.a)
SYNOPSIS
#include <tiuser.h>
int t_connect(
int fd ,
struct t_call *sndcall ,
int struct *rcvcall );
DESCRIPTION
This function enables a transport user to request a connection to the
specified destination transport user. The fd parameter identifies the
local transport endpoint where communication will be established, while
sndcall and rcvcall point to a t_call structure which contains the
following members:
struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
int sequence;
The sndcall parameter specifies information needed by the transport
provider to establish a connection and rcvcall specifies information that
is associated with the newly established connection.
The netbuf structure is described in intro. 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 are passed to
the a 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
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t_connect(3) CLIX t_connect(3)
negotiate protocol options by setting the len field of opt to zero. In
this case, the provider may use default options.
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 by
t_open() or t_getinfo(). If the len [see netbuf in intro field of udata
is zero in sndcall, no data is 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 field
[see netbuf in intro 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 t_connect().
By default, t_connect() executes in synchronous mode and waits for the
destination user's response before returning control to the local user. A
successful return value of zero indicates that the requested connection
has been established. However, if O_NDELAY is set with t_open() [or
fcntl(), t_connect() executes in asynchronous mode. In this case, the
call will not wait for the remote user's response, but will return control
to the local user and return -1 with t_errno set to TNODATA to indicate
that the connection is not yet established. In this way, the function
initiates the connection establishment procedure by sending a connect
request to the destination transport user.
RETURN VALUES
The t_connect() function returns 0 on success and -1 on failure, and
t_errno is set to indicate the error.
ERRORS
On failure, t_errno 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]
The O_NDELAY 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
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t_connect(3) CLIX t_connect(3)
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.
[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 T_DATAXFER, 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.
RELATED INFORMATION
Functions: t_accept(3), t_getinfo(3), t_listen(3), t_open(3),
t_optmgmt(3), t_rcvconnect(3).
Miscellany: intro(4)
AT&T UNIX System V Network Programmer's Guide
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