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Technical Reference: Communications, Volume 2
Gets protocol-specific service
information.
Transport Layer Interface Library
(libtli.a)
#include <tiuser.h>
int t_getinfo(fd, info)
int fd;
struct t_info * info;
The t_getinfo
subroutine returns the current characteristics of the underlying transport
protocol associated with fd file descriptor. The
t_info structure is used to return the same information returned by
the t_open subroutine. This
function enables a transport user to access this information during any phase
of communication.
| fd
| Specifies the file descriptor.
|
| info
| Points to a t_info structure that contains the following
members:
long addr;
long options;
long tsdu;
long etsdu;
long connect;
long discon;
long servtype;
The values of the fields have the
following meanings:
- addr
- A value greater than or equal to 0 indicates the maximum size of a
transport protocol 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 0 indicates the maximum number of bytes
of protocol-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 0 specifies the maximum size of a transport service
data unit (TSDU); a value of 0 specifies that the transport provider does
not support the concept of TSDU, although it does support the sending of a
data stream having no logical boundaries preserved across a connection; a
value of -1 specifies that there is no limit on the size of a TSDU; and a
value of -2 specifies that the transfer of normal data is not supported by the
transport provider.
- etsdu
- A value greater than 0 specifies the maximum size of an expedited
transport service data unit (ETSDU); a value of 0 specifies that the
transport provider does not support the concept of ETSDU, although it does
support the sending of an expedited data stream having 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 expedited data is not supported by the transport provider.
- connect
- A value greater than or equal to 0 specifies 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 connection establishment
functions.
- discon
- A value greater than or equal to 0 specifies the maximum amount of data
that may be associated with the t_snddis
and t_rcvdis subroutines; a value of
-1 specifies that there is no limit on the amount of data sent with these
abortive release functions; and a value of -2 specifies that the
transport provider does not allow data to be sent with the abortive release
functions.
- servtype
- This field specifies the service type supported by the transport
provider.
If a transport user is concerned
with protocol independence, the sizes may be accessed to determine how large
the buffers must be to hold each piece of information. Alternatively,
the t_alloc subroutine may be used to
allocate these buffers. An error will result if a transport user
exceeds the allowed data size on any function. The value of each field
can change as a result of option negotiation; the t_getinfo
subroutine enables a user to retrieve the current characteristics.
|
On successful completion, the
t_getinfo subroutine returns a value of 0. Otherwise, it
returns a value of -1, and the t_errno variable is set to indicate
the error.
The servtype field of
the info parameter may specify 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 connectionless-mode service. For
this service type, the t_open subroutine returns -2 for the values
in the etsdu, connect, and discon
fields.
|
In unsuccessful, the
t_errno variable is set to one of the following:
| TBADF
| The specified file descriptor does not refer to a transport end
point.
|
| TSYSERR
| A system error has occurred during execution of this function.
|
This subroutine is part of Base
Operating System (BOS) Runtime.
The t_alloc subroutine, t_open subroutine, t_rcvdis subroutine and t_snddis subroutine.
List of Streams
Programming Reference and STREAMS Overview in
AIX 5L Version 5.1 Communications Programming
Concepts.
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