t_open(3xti)t_open(3xti)Namet_open - establish a transport endpoint
Syntax
#include <xti.h>
#include <fcntl.h>
int t_open(name, oflag, info)
char *name;
int oflag;
struct t_info *info;
Arguments
name Points to a transport provider identifier.
oflag Identifies any open flags as in The oflag argument is con‐
structed from O_RDWR optionally ORed with O_NONBLOCK. These
flags are defined by the header file <fcntl.h>.
info Returns various default characteristics of the underlying
transport protocol by setting fields in the info structure.
This argument points to a structure that contains the follow‐
ing members:
long addr /* max size of the transport protocol address
*/
long options /* max number of bytes of protocol specific
options */
long tsdu /* max size of a transport service data unit
(TSDU) */
long etsdu /* max size of expedited transport service
data unit (ETSDU) */
long connect /* max amount of data allowed on connection
establishment functions */
long discon /* max amount of data allowed on and functions
*/
long servtype /* service type supported by the transport
provider */
The values of the fields have the following meanings:
addr A value greater than or equal to zero indi‐
cates the maximum size of a transport proto‐
col address; a value of -1 specifies that
there is no limit on the address size; and a
value of -2 specifies that the transport
provider does not provide user access to
transport protocol addresses.
options A value greater than or equal to zero indi‐
cates the maximum number of bytes of proto‐
col-specific options supported by the
provider; a value of -1 specifies that there
is no limit on the option size; and a value
of -2 specifies that the transport provider
does not support user-settable options.
tsdu A value greater than zero specifies the max‐
imum size of a transport service data unit
(TSDU); a value of zero specifies that the
transport provider does not support the con‐
cept of TSDU; although it does support the
sending of a data stream with no logical
boundaries preserved across a connection; a
value of -1 specifies that there is no limit
on the size of an ETSDU; and a value of -2
specifies that the transfer of normal data
is not supported by the transport provider.
etsdu A value greater than zero specifies the max‐
imum size of an expedited transport service
data unit (ETSDU); a value zero specifies
that the transport provider does not support
the concept of ETSDU, although it does sup‐
port the sending of an expedited data stream
with no logical boundaries preserved across
a connection; a value of -1 specifies that
there is no limit on the size of an ETSDU;
and a value -2 specifies that the transfer
of expedited data is not supported by the
transport provider.
connect A value greater than or equal to zero speci‐
fies the maximum amount of data that may be
associated with connection establishment
functions; a value of -1 specifies that
there is no limit on the amount of data sent
during connection establishment; and a value
of -2 specifies that the transport provider
does not allow data to be sent with connec‐
tion establishment functions.
discon A value greater than or equal to zero speci‐
fies the maximum amount of data that may be
associated with the and functions; a value
of -1 specifies that there is no limit on
the amount of data sent with these abortive
release functions; and a -2 specifies that
the transport provider does not allow data
to be sent with abortive release functions.
servtype This field specifies the service type sup‐
ported by the transport provider, as
described.
If a transport user is concerned with protocol independence, the sizes
can be accessed to determine how large the buffers must be to hold each
piece of information. Alternately, the function may be used to allocate
these buffers. An error will result if a transport user exceeds the
allowed data size on any function.
The servtype field of info specifies one of the following values on
return.
T_COTS The transport provider supports a connection-
mode service but does not support the optional
orderly release facility.
T_COTS_ORD The transport provider supports a connection-
mode service with the optional orderly release
facility.
T_CLTS The transport provider supports a connection‐
less-mode service. For this service type,
returns -2 for etsdu, connect, and discon.
A single transport endpoint may support only one of the above services
at one time. If info is set to NULL by the transport user, no protocol
information is returned by
Description
The function must be called as the first step in the initialization of
a transport endpoint. This function establishes a transport endpoint
by supplying a transport provider identifier that indicates a particu‐
lar transport provider, that is a transport protocol, and returns a
file descriptor that identifies that endpoint.
The function returns a file descriptor that is used by all subsequent
functions to identify that particular local transport endpoint.
──────────────────────────────────────────
Parameters Before Call After Call
──────────────────────────────────────────
name x /
oflag x /
info->addr / x
info->options / x
info->tsdu / x
info->etsdu / x
info->connect / x
info->discon / x
info->servtype / x
──────────────────────────────────────────
Return Values
Upon successful completion, returns a file descriptor. On failure, -1
is returned, and t_errno is set to indicate the error.
Diagnostics
On failure, t_errno is set to one of the following:
[TBADFLAG] An invalid flag is specified.
[TBADNAME] Invalid transport provider name.
[TSYSERR] A system error has occurred during execution of
this function.
See Alsoopen(2)t_open(3xti)
