t_getinfo(3N) NETWORK FUNCTIONS t_getinfo(3N)
NAME
tgetinfo - get protocol-specific service information
SYNOPSIS
#include <tiuser.h>
int tgetinfo(fd, info)
int fd;
struct tinfo *info;
DESCRIPTION
This function returns the current characteristics of the
underlying transport protocol associated with file descrip-
tor fd. The info structure is used to return the same
information returned by topen. This function enables a
transport user to access this information during any phase
of communication.
This argument points to a tinfo structure, which contains
the following 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 an 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 tsnddis and trcvdis 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 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 zero indi-
cates 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 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
Last change: Networking Support Utilities 1
t_getinfo(3N) NETWORK FUNCTIONS t_getinfo(3N)
sending of a data stream with no logical boun-
daries 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 sup-
ported 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 of zero specifies
that the transport provider does not support
the concept of ETSDU, although it does support
the sending of an expedited data stream with
no logical boundaries preserved across a con-
nection; 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 pro-
vider.
connect A value greater than or equal to zero speci-
fies the maximum amount of data that may be
associated with connection establishment func-
tions; 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 estab-
lishment functions.
discon A value greater than or equal to zero speci-
fies the maximum amount of data that may be
associated with the tsnddis and trcvdis
functions; 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 abor-
tive release functions.
servtype This field specifies the service type sup-
ported by the transport provider, as described
below.
If a transport user is concerned with protocol independence,
the above sizes may be accessed to determine how large the
buffers must be to hold each piece of information. Alterna-
tively, the talloc 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 value of each
field may change as a result of option negotiation, and
tgetinfo enables a user to retrieve the current
Last change: Networking Support Utilities 2
t_getinfo(3N) NETWORK FUNCTIONS t_getinfo(3N)
characteristics.
The servtype field of info may specify one of the following
values on return:
TCOTS The transport provider supports a
connection-mode service but does not support
the optional orderly release facility.
TCOTSORD The transport provider supports a
connection-mode service with the optional
orderly release facility.
TCLTS The transport provider supports a
connectionless-mode service. For this ser-
vice type, topen will return -2 for etsdu,
connect, and discon. On failure, terrno may
be set to one of the following:
[TBADF] The specified file descriptor does not refer
to a transport endpoint.
[TSYSERR] A system error has occurred during execution
of this function.
SEE ALSO
topen(3N).
UNIX System V Network Programmer's Guide.
DIAGNOSTICS
tgetinfo returns 0 on success and -1 on failure and terrno
is set to indicate the error.
Last change: Networking Support Utilities 3