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t_getinfo(3)
NAME
t_getinfo - Get protocol-specific information
SYNOPSIS
#include <xti.h>
int t_getinfo(
int fd,
struct t_info *info );
LIBRARY
XTI Library (libxti.a)
STANDARDS
Interfaces documented on this reference page conform to industry standards
as follows:
t_getinfo(): XNS4.0, XNS5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
PARAMETERS
The following table summarizes the relevance of input and output parameter
data before and after t_info() is called:
_________________________________________
Parameter Before Call After Call
_________________________________________
fd y n
info->addr n y
info->options n y
info->tsdu n y
info->etsdu n y
info->connect n y
info->discon n y
info->servtype n y
info->options n y
_________________________________________
Notes to table:
y This a meaningful parameter.
n This is not a meaningful parameter.
fd Specifies a file descriptor returned by the t_open() function that
identifies the local transport endpoint.
info
Points to a type t_info structure that is returned when t_getinfo()
executes. Parameters defined by the t_info structure specify
characteristics of the underlying transport protocol associated with
the fd file descriptor.
When the info parameter is set to the null pointer value by a transport
user, no protocol information is returned by the t_getinfo() function.
When a transport user must preserve protocol independence, data length
information defined by members of the t_info structure pointed to by
the info parameter may be accessed to determine how large data buffers
must be to hold exchanged data. Alternatively, the t_alloc() function
may be used to allocate necessary data buffers. An error results when a
transport user exceeds the allowed data length during any data
exchange.
Values associated with parameters of the t_info structure may change as
the result of protocol option negotiations during initialization of a
connection. The t_info structure has the following members:
addr
Specifies the permitted number of bytes in the protocol address. A
value greater than zero indicates the maximum number of permitted
bytes in a protocol address. A value of -1 specifies that there is
no limit on the protocol address size. A value of -2 specifies that
the transport provider does not permit the transport user access to
the protocol addresses.
options
Specifies the permitted number of bytes of options. A value greater
than zero indicates the maximum number of bytes of protocol-
specific options supported by the transport provider. A value of
-1 specifies that there is no limit to the number of options bytes.
A value of -2 specifies that the transport provider does not permit
a transport user to set options.
tsdu
Specifies the permitted number of bytes in a Transport Service Data
Unit (TSDU). A value greater than zero specifies the maximum number
of bytes in a TSDU message. A value of zero specifies that the
transport provider does not support TSDU data exchanges, 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 to the number of bytes in a TSDU data
exchange. A value of -2 specifies that the transfer of normal data
is not supported by the transport provider.
etsdu
Specifies the permitted number of bytes in an Expedited Transport
Service Data Unit (ETSDU). A value greater than zero specifies the
maximum number of bytes in an ETSDU data exchange. A value of zero
specifies that the transport provider does not support ETSDU data
exchanges, although it does support 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
number of bytes in an ETSDU data exchange. A value of -2 specifies
that the transfer of expedited data is not supported by the
transport provider.
connect
Specifies the permitted number of bytes of data in a connect
request. A value greater than zero specifies the maximum number of
data bytes that may be exchanged using the t_connect() or
t_rcvconnect() function. A value of -2 specifies that the transport
provider does not permit data to be sent when a connection is
established.
discon
Specifies the permitted number of bytes of data in a disconnect
request. A value greater than zero specifies the maximum number of
data bytes that may be exchanged using the t_snddis() or t_rcvdis()
function. A value of -1 specifies that there is no limit to the
number of data bytes that may be sent when a connection is closed
using these abortive release functions. A value of -2 specifies
that the transport provider does not permit data to be sent with an
abortive release function.
servtype
Specifies only one of the following types of service supported by
the transport provider:
T_COTS
The transport provider supports connection-mode service but
does not support the optional orderly release facility.
T_COTS_ORD
The transport provider supports connection-mode service with
the optional orderly release facility.
T_CLTS
The transport provider supports connectionless mode service.
For this service type, the t_open() function returns the value
-2 for the etsdu, connect, and discon parameters.
flags
Specifies other information about the transport provider. If the
T_SENDZERO bit is set in flags, this indicates that the underlying
transport provider supports sending zero-length TSDUs.
DESCRIPTION
The t_getinfo() function is an XTI general utility function that provides
information about the underlying transport protocol associated with a file
descriptor previously returned by the t_open() function. The t_getinfo()
function returns the same protocol-specific information as does t_open() in
theinfo parameter.
ERRORS
If the t_getinfo() function fails, t_errno may be set to one of the
following values:
[TBADF]
File descriptor fd does not refer to a valid transport endpoint.
[TSYSERR]
A system error occurred during execution of this function.
[TPROTO]
This error indicates that a communication problem has been detected
between XTI and the transport provider for which there is no other
suitable XTI(t_errno).
VALID STATES
The t_getinfo() function can be called in any transport provider state
except T_UNINIT.
RETURN VALUE
Upon successful completion, a value of 0 (zero) is returned. Otherwise, a
value of -1 is returned and t_errno is set to indicate the error.
SEE ALSO
Functions: t_alloc(3), t_open(3)
Standards: standards(5)
Network Programmer's Guide
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