T_CONNECT(3N)                        SysV                        T_CONNECT(3N)



NAME
     t_connect - establish a connection with another transport user

SYNOPSIS
     #include <tiuser.h>

     int t_connect(fd, sndcall, rcvcall)
     int fd;
     struct t_call *sndcall;
     struct t_call *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 t_call structure which 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.

     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(3N) or t_getinfo(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 t_connect.

     By default, t_connect executes in synchronous mode, and will wait for the
     destination user's response before returning control to the local user.
     A successful return (that is return value of zero) indicates that the
     requested connection has been established.  However, if O_NDELAY is set
     (via 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 immediately to the local user and return -1 with t_errno
     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.

DIAGNOSTICS
     t_connect 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]          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 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.

SEE ALSO
     intro(3), t_accept(3N), t_getinfo(3N), t_listen(3N), t_open(3N),
     t_optmgmt(3N), t_rcvconnect(3N)
     Programming with the SysV Transport Interface