T_OPTMGMT(3N)                        SysV                        T_OPTMGMT(3N)



NAME
     t_optmgmt - manage options for a transport endpoint

SYNOPSIS
     #include <tiuser.h>

     int t_optmgmt(fd, req, ret)
     int fd;
     struct t_optmgmt *req;
     struct t_optmgmt *ret;

DESCRIPTION
     The t_optmgmt function enables a transport user to retrieve, verify, or
     negotiate protocol options with the transport provider.  fd identifies a
     bound transport endpoint.

     The req and ret arguments point to a t_optmgmt structure containing the
     following members:

          struct netbuf opt;
          long flags;

     The opt field identifies protocol options and the flags field is used to
     specify the action to take with those options.

     The options are represented by a netbuf (see intro(3); also for len, buf
     and maxlen) structure in a manner similar to the address in t_bind.  req
     is used to request a specific action of the provider and to send options
     to the provider.  len specifies the number of bytes in the options, buf
     points to the options buffer, and maxlen has no meaning for the req
     argument.  The transport provider may return options and flag values to
     the user through ret.  For ret, maxlen specifies the maximum size of the
     options buffer and buf points to the buffer where the options are to be
     placed.  On return, len specifies the number of bytes of options
     returned.  maxlen has no meaning for the req argument, but must be set in
     the ret argument to specify the maximum number of bytes the options
     buffer can hold.  The actual structure and content of the options is
     imposed by the transport provider.

     The flags field of req can specify one of the following actions:

     T_NEGOTIATE    This action enables the user to negotiate the values of
                    the options specified in req with the transport provider.
                    The provider will evaluate the requested options and
                    negotiate the values, returning the negotiated values
                    through ret.

     T_CHECK        This action enables the user to verify whether the options
                    specified in req are supported by the transport provider.
                    On return, the flags field of ret will have either
                    T_SUCCESS or T_FAILURE set to indicate to the user whether
                    the options are supported.  These flags are only
                    meaningful for the T_CHECK request.

     T_DEFAULT      This action enables a user to retrieve the default options
                    supported by the transport provider into the opt field of
                    ret.  In req, the len field of opt must be zero and the
                    buf field may be NULL.

     If issued as part of the connectionless-mode service, t_optmgmt may block
     due to flow control constraints.  The function will not complete until

     the transport provider has processed all previously sent data units.

DIAGNOSTICS
     t_optmgmt 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.

     [TACCES]            The user does not have permission to negotiate the
                         specified options.

     [TBADOPT]           The specified protocol options were in an incorrect
                         format or contained illegal information.

     [TBADFLAG]          An invalid flag was specified.

     [TBUFOVFLW]         The number of bytes allowed for an incoming argument
                         is not sufficient to store the value of that
                         argument.  The information to be returned in ret will
                         be discarded.

     [TSYSERR]           A system error has occurred during execution of this
                         function.

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