t_getinfo(3xti)

Name

t_getinfo − get protocol-specific service information

Syntax

#include <xti.h>
int t_getinfo(fd, info)
int fd;
struct t_info *info;

Arguments

fd
Identifies the file descriptor that is associated with the underlying transport protocol from which the current characteristics are to be returned.

info
Specifies the structure that is used to return the same information returned by t_open(). Points to a t_info 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 t_snddis() and t_rcvdis() 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 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 zero 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 zero specifies the maximum size of a transport service data unit (TSDU); a value of zero specifies that the transport provider does not support the concept 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 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 zero specifies the maximum 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 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 size of 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 zero 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 zero specifies the maximum amount of data that may be associated with the t_snddis() and t_rcvdis() functions; a value -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, as described.

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() function can be used to allocate these buffers. An error results 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 t_getinfo() enables a user to retrieve the current characteristics of the underlying transport protocol.

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 connectionless-mode service. For this service type, t_open() returns -2 for ETSDU, connect and discon.

Description

This function returns the current characteristics of the underlying transport protocol associated with file descriptor fd. The info structure is used to return the same information returned by t_open(). This function enables a transport user to access this information during any phase of communications.

Parameters	Before Call	After Call
fd	x	/
info->addr	/	x
info->options	/	x
info->tsdu	/	x
info->etsdu	/	x
info->connect	/	x
info->discon	/	x
info->sertype	/	x

Return Value

Upon successful completion, a value of 0 is returned. On failure, a value of -1 is returned, and t_errno is set to indicate the error.

Diagnostics

On failure, t_errno is set to one of the following:

[TBADF] The specified file descriptor does not refer to a transport endpoint.

[TNOTSUPPORT] This function is not supported by the current implementation of XTI.

[TSYSERR] A system error has occurred during execution of this function.

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