T_OPTMGMT(3N) INTERACTIVE UNIX System 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 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.
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T_OPTMGMT(3N) INTERACTIVE UNIX System T_OPTMGMT(3N)
T_CHECK This action enables the user to verify
whether the options specified in req are sup-
ported 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.
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T_OPTMGMT(3N) INTERACTIVE UNIX System T_OPTMGMT(3N)
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.
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).
Programmer's Guide.
DIAGNOSTICS
The t_optmgmt function returns 0 on success and -1 on
failure, and t_errno is set to indicate the error.
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