Sun Microsystems, Inc. gratefully acknowledges The Open Group for
permission to reproduce portions of its copyrighted documentation.
Original documentation from The Open Group can be obtained online at
http://www.opengroup.org/bookstore/.

The Institute of Electrical and Electronics Engineers and The Open
Group, have given us permission to reprint portions of their
documentation.

In the following statement, the phrase ``this text'' refers to portions
of the system documentation.

Portions of this text are reprinted and reproduced in electronic form
in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition,
Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6,
Copyright (C) 2001-2004 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy
between these versions and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee
document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html.

This notice shall appear on any product containing this material.

The contents of this file are subject to the terms of the
Common Development and Distribution License (the "License").
You may not use this file except in compliance with the License.

You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
or http://www.opensolaris.org/os/licensing.
See the License for the specific language governing permissions
and limitations under the License.

When distributing Covered Code, include this CDDL HEADER in each
file and include the License file at usr/src/OPENSOLARIS.LICENSE.
If applicable, add the following below this CDDL HEADER, with the
fields enclosed by brackets "[]" replaced with your own identifying
information: Portions Copyright [yyyy] [name of copyright owner]


Portions Copyright 1989 AT&T
Copyright 1994, The X/Open Company Ltd. All Rights Reserved.
Portions Copyright (c) 1998, Sun Microsystems, Inc. , All Rights Reserved.

t_alloc - allocate a library structure

#include <xti.h>




void *t_alloc(int fd, int struct_type, int fields);

This routine is part of the XTI interfaces which evolved from the TLI interfaces. XTI represents the future evolution of these interfaces. However, TLI interfaces are supported for compatibility. When using a TLI routine that has the same name as an XTI routine, a different header file, tiuser.h, must be used. Refer to the section, TLI COMPATIBILITY, for a description of differences between the two interfaces.

The t_alloc() function dynamically allocates memory for the various transport function argument structures as specified below. This function will allocate memory for the specified structure, and will also allocate memory for buffers referenced by the structure.

The structure to allocate is specified by struct_type and must be one of the following:

T_BIND struct t_bind
T_CALL struct t_call
T_OPTMGMT struct t_optmgmt
T_DIS struct t_discon
T_UNITDATA struct t_unitdata
T_UDERROR struct t_uderr
T_INFO struct t_info

where each of these structures may subsequently be used as an argument to one or more transport functions.

Each of the above structures, except T_INFO, contains at least one field of type struct netbuf. For each field of this type, the user may specify that the buffer for that field should be allocated as well. The length of the buffer allocated will be equal to or greater than the appropriate size as returned in the info argument of t_open(3NSL) or t_getinfo(3NSL). The relevant fields of the info argument are described in the following list. The fields argument specifies which buffers to allocate, where the argument is the bitwise-or of any of the following: T_ADDR

T_OPT T_UDATA T_ALL

For each relevant field specified in fields, t_alloc() will allocate memory for the buffer associated with the field, and initialize the len field to zero and the buf pointer and maxlen field accordingly. Irrelevant or unknown values passed in fields are ignored. Since the length of the buffer allocated will be based on the same size information that is returned to the user on a call to t_open(3NSL) and t_getinfo(3NSL), fd must refer to the transport endpoint through which the newly allocated structure will be passed. In the case where a T_INFO structure is to be allocated, fd may be set to any value. In this way the appropriate size information can be accessed. If the size value associated with any specified field is T_INVALID, t_alloc() will be unable to determine the size of the buffer to allocate and will fail, setting t_errno to TSYSERR and errno to EINVAL. See t_open(3NSL) or t_getinfo(3NSL). If the size value associated with any specified field is T_INFINITE, then the behavior of t_alloc() is implementation-defined. For any field not specified in fields, buf will be set to the null pointer and len and maxlen will be set to zero. See t_open(3NSL) or t_getinfo(3NSL).

The pointer returned if the allocation succeeds is suitably aligned so that it can be assigned to a pointer to any type of object and then used to access such an object or array of such objects in the space allocated.

Use of t_alloc() to allocate structures will help ensure the compatibility of user programs with future releases of the transport interface functions.

On successful completion, t_alloc() returns a pointer to the newly allocated structure. On failure, a null pointer is returned.

ALL - apart from T_UNINIT

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

TNOSTRUCTYPE TPROTO TSYSERR

The XTI and TLI interface definitions have common names but use different header files. This, and other semantic differences between the two interfaces are described in the subsections below.

The XTI interfaces use the header file, xti.h. TLI interfaces should not use this header. They should use the header:

#include <tiuser.h>

The t_errno values that can be set by the XTI interface and cannot be set by the TLI interface are: TPROTO

TNOSTRUCTYPE

Assume that the value associated with any field of struct t_info (argument returned by t_open() or t_getinfo()\|) that describes buffer limits is -1. Then the underlying service provider can support a buffer of unlimited size. If this is the case, t_alloc() will allocate a buffer with the default size 1024 bytes, which may be handled as described in the next paragraph.

If the underlying service provider supports a buffer of unlimited size in the netbuf structure (see t_connect(3NSL)), t_alloc() will return a buffer of size 1024 bytes. If a larger size buffer is required, it will need to be allocated separately using a memory allocation routine such as malloc(3C). The buf and maxlen fields of the netbuf data structure can then be updated with the address of the new buffer and the 1024 byte buffer originally allocated by t_alloc() can be freed using free(3C).

Assume that the value associated with any field of struct t_info (argument returned by t_open() or t_getinfo() \|) that describes nbuffer limits is -2. Then t_alloc() will set the buffer pointer to NULL and the buffer maximum size to 0, and then will return success (see t_open(3NSL) or t_getinfo(3NSL)).

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE ATTRIBUTE VALUE

MT Level Safe

free (3C), malloc (3C), t_connect (3NSL), t_free (3NSL), t_getinfo (3NSL), t_open (3NSL), attributes (7)