TOPTMGMT(3N-SVR4)  RISC/os Reference Manual   TOPTMGMT(3N-SVR4)



NAME
     t_optmgmt - manage options for a transport endpoint

SYNOPSIS
     #include <tiuser.h>

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

DESCRIPTION
     The toptmgmt 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 toptmgmt 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 speci-
     fies 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 tran-
     sport 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



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TOPTMGMT(3N-SVR4)  RISC/os Reference Manual   TOPTMGMT(3N-SVR4)



                    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 sup-
                    ported.  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,
     toptmgmt may block due to flow control constraints.  The
     function will not complete until the transport provider has
     processed all previously sent data units.

     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 exe-
                         cution of this function.

SEE ALSO
     intro(3), t_getinfo(3N), t_open(3N).

DIAGNOSTICS
     toptmgmt returns 0 on success and -1 on failure and t_errno
     is set to indicate the error.





 Page 2                 Printed 11/19/92